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Liu W, Liao SS, Bao MH, Huo DL, Cao J, Zhao ZJ. Lactating striped hamsters (Cricetulus barabensis) do not decrease the thermogenic capacity to cope with extreme cold temperature. ZOOLOGY 2024; 166:126195. [PMID: 39128254 DOI: 10.1016/j.zool.2024.126195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 07/20/2024] [Accepted: 07/25/2024] [Indexed: 08/13/2024]
Abstract
For small non-hibernating mammals, a high thermogenic capacity is important to increase activity levels in the cold. It has been previously reported that lactating females decrease their thermogenic activity of brown adipose tissue (BAT), whereas their capacity to cope with extreme cold remains uncertain. In this study we examined food intake, body temperature and locomotor behavior, resting metabolic rate, non-shivering thermogenesis, and cytochrome c oxidase activity, and the rate of state 4 respiration of liver, skeletal muscle, and BAT in striped hamsters (Cricetulus barabensis) at peak lactation and non- breeding hamsters (controls). The lactating hamsters and non- breeding controls were acutely exposed to -15°C, and several markers indicative of thermogenic capacity were examined. In comparison to non-breeding females, lactating hamsters significantly increased food intake and body temperature, but decreased locomotor behavior, and the BAT mass, indicative of decreased BAT thermogenesis at peak lactation. Unexpectedly, lactating hamsters showed similar body temperature, resting metabolic rate, non-shivering thermogenesis with non-breeding females after acute exposure to -15°C. Furthermore, cytochrome c oxidase activity of liver, skeletal muscle and BAT, and serum thyroid hormone concentration, and BAT uncoupling protein 1 expression, in lactating hamsters were similar with that in non-breeding hamsters after acute extreme cold exposure. This suggests that lactating females have the same thermogenic capacity to survive cold temperatures compared to non-breeding animals. This is particularly important for females in the field to cope with cold environments during the period of reproduction. Our findings indicate that the females during lactation, one of the highest energy requirement periods, do not impair their thermogenic capacity in response to acute cold exposure.
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Affiliation(s)
- Wei Liu
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Sha-Sha Liao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Meng-Huan Bao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Da-Liang Huo
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Jing Cao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China; Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China
| | - Zhi-Jun Zhao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China; Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China.
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2
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Grosiak M, Koteja P, Hambly C, Speakman JR, Sadowska ET. Limits to sustained energy intake. XXXIV. Can the heat dissipation limit (HDL) theory explain reproductive aging? J Exp Biol 2024; 227:jeb246592. [PMID: 38264846 DOI: 10.1242/jeb.246592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 01/11/2024] [Indexed: 01/25/2024]
Abstract
According to the heat dissipation limit (HDL) theory, reproductive performance is limited by the capacity to dissipate excess heat. We tested the novel hypotheses that (1) the age-related decline in reproductive performance is due to an age-related decrease of heat dissipation capacity and (2) the limiting mechanism is more severe in animals with high metabolic rates. We used bank voles (Myodes glareolus) from lines selected for high swim-induced aerobic metabolic rate, which have also increased basal metabolic rate, and unselected control lines. Adult females from three age classes - young (4 months), middle-aged (9 months) and old (16 months) - were maintained at room temperature (20°C), and half of the lactating females were shaved to increase heat dissipation capacity. Old females from both selection lines had a decreased litter size, mass and growth rate. The peak-lactation average daily metabolic rate was higher in shaved than in unshaved mothers, and this difference was more profound among old than young and middle-aged voles (P=0.02). In females with large litters, milk production tended to be higher in shaved (least squares mean, LSM±s.e.: 73.0±4.74 kJ day-1) than in unshaved voles (61.8±4.78 kJ day-1; P=0.05), but there was no significan"t effect of fur removal on the growth rate [4.47±2.29 g (4 days-1); P=0.45]. The results provide mixed support of the HDL theory and no support for the hypotheses linking the differences in reproductive aging with either a deterioration in thermoregulatory capability or genetically based differences in metabolic rate.
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Affiliation(s)
- Marta Grosiak
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Krakow 30-387, Poland
| | - Paweł Koteja
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Krakow 30-387, Poland
| | - Catherine Hambly
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - John R Speakman
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
| | - Edyta T Sadowska
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Krakow 30-387, Poland
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3
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Khera M, Arbuckle K, Mwanguhya F, Kyabulima S, Mwesige K, Businge R, Blount JD, Cant MA, Nichols HJ. Small increases in ambient temperature reduce offspring body mass in an equatorial mammal. Biol Lett 2023; 19:20230328. [PMID: 37990567 PMCID: PMC10715294 DOI: 10.1098/rsbl.2023.0328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 11/02/2023] [Indexed: 11/23/2023] Open
Abstract
Human-induced climate change is leading to temperature rises, along with increases in the frequency and intensity of heatwaves. Many animals respond to high temperatures through behavioural thermoregulation, for example by resting in the shade, but this may impose opportunity costs by reducing foraging time (therefore energy supply), and so may be most effective when food is abundant. However, the heat dissipation limit (HDL) theory proposes that even when energy supply is plentiful, high temperatures can still have negative effects. This is because dissipating excess heat becomes harder, which limits processes that generate heat such as lactation. We tested predictions from HDL on a wild, equatorial population of banded mongooses (Mungos mungo). In support of the HDL theory, higher ambient temperatures led to lighter pups, and increasing food availability made little difference to pup weight under hotter conditions. This suggests that direct physiological constraints rather than opportunity costs of behavioural thermoregulation explain the negative impact of high temperatures on pup growth. Our results indicate that climate change may be particularly important for equatorial species, which often experience high temperatures year-round so cannot time reproduction to coincide with cooler conditions.
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Affiliation(s)
- Monil Khera
- Department of Biosciences, Swansea University, Swansea SA2 8PP, UK
| | - Kevin Arbuckle
- Department of Biosciences, Swansea University, Swansea SA2 8PP, UK
| | - Francis Mwanguhya
- Banded Mongoose Research Project, Queen Elizabeth National Park, Kasese District, Uganda
| | - Solomon Kyabulima
- Banded Mongoose Research Project, Queen Elizabeth National Park, Kasese District, Uganda
| | - Kenneth Mwesige
- Banded Mongoose Research Project, Queen Elizabeth National Park, Kasese District, Uganda
| | - Robert Businge
- Banded Mongoose Research Project, Queen Elizabeth National Park, Kasese District, Uganda
| | | | - Michael A. Cant
- Centre for Ecology and Conservation, University of Exeter, Cornwall, UK
| | - Hazel J. Nichols
- Department of Biosciences, Swansea University, Swansea SA2 8PP, UK
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4
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Yang R, Cao J, Speakman JR, Zhao Z. Limits to sustained energy intake. XXXIII. Thyroid hormones play important roles in milk production but do not define the heat dissipation limit in Swiss mice. J Exp Biol 2023; 226:jeb245393. [PMID: 37767758 DOI: 10.1242/jeb.245393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 09/22/2023] [Indexed: 09/29/2023]
Abstract
The limits to sustained energy intake set physiological upper boundaries that affect many aspects of human and animal performance. The mechanisms underlying these limits, however, remain unclear. We exposed Swiss mice to either supplementary thyroid hormones (THs) or the inhibitor methimazole during lactation at 21 or 32.5°C, and measured food intake, resting metabolic rate (RMR), milk energy output (MEO), serum THs and mammary gland gene expression of females, and litter size and mass of their offspring. Lactating females developed hyperthyroidism following exposure to supplementary THs at 21°C, but they did not significantly change body temperature, asymptotic food intake, RMR or MEO, and litter and mass were unaffected. Hypothyroidism, induced by either methimazole or 32.5°C exposure, significantly decreased asymptotic food intake, RMR and MEO, resulting in significantly decreased litter size and litter mass. Furthermore, gene expression of key genes in the mammary gland was significantly decreased by either methimazole or heat exposure, including gene expression of THs and prolactin receptors, and Stat5a and Stat5b. This suggests that endogenous THs are necessary to maintain sustained energy intake and MEO. Suppression of the thyroid axis seems to be an essential aspect of the mechanism by which mice at 32.5°C reduce their lactation performance to avoid overheating. However, THs do not define the upper limit to sustained energy intake and MEO at peak lactation at 21°C. Another, as yet unknown, factor prevents supplementary thyroxine exerting any stimulatory metabolic impacts on lactating mice at 21°C.
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Affiliation(s)
- Rui Yang
- College of Life and Environmental Science, Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China
| | - Jing Cao
- College of Life and Environmental Science, Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China
| | - John R Speakman
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - Zhijun Zhao
- College of Life and Environmental Science, Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China
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5
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Hoffman JM, Schmitz B, Pfabe JU, Ohrnberger SA, Valencak TG. Lactating SKH-1 furless mice prioritize own comfort over growth of their pups. J Comp Physiol B 2023; 193:453-459. [PMID: 37243858 PMCID: PMC10985496 DOI: 10.1007/s00360-023-01498-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 05/10/2023] [Accepted: 05/16/2023] [Indexed: 05/29/2023]
Abstract
Lactation is the most energetically demanding physiological process that occurs in mammalian females, and as a consequence of this energy expenditure, lactating females produce an enormous amount of excess heat. This heat is thought to limit the amount of milk a mother produces, and by improving heat dissipation, females may improve their milk production and offspring quality. Here we used SKH-1 hairless mice as a natural model of improved heat dissipation. Lactating mothers were given access to a secondary cage to rest away from their pups, and this secondary cage was kept either at room temperature (22 °C) in the control rounds or cooled to 8 °C in the experimental groups. We hypothesized that the cold exposure would maximize the heat dissipation potential, leading to increased milk production and healthier pups even in the hairless mouse model. However, we found the opposite, where cold exposure allowed mothers to eat more food, but they produced smaller weight pups at the end of lactation. Our results suggest that mothers prioritize their own fitness, even if it lowers the fitness of their offspring in this particular mouse strain. This maternal-offspring trade-off is interesting and requires future studies to understand the full interaction of maternal effects and offspring fitness in the light of the heat dissipation limitation.
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Affiliation(s)
- Jessica M Hoffman
- Department of Biological Sciences, Augusta University, 1120 15th Street, Augusta, GA, 30912, USA
| | - Britta Schmitz
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Johannes U Pfabe
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Sarah A Ohrnberger
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Teresa G Valencak
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria.
- College of Animal Sciences, Zhejiang University, Zijingang Campus, 866 Yuhangtang Road, Hangzhou, 310058, People's Republic of China.
- Agency for Health and Food Safety, Spargelfeldstrasse 191, 1220, Vienna, Austria.
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6
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McGrosky A, Pontzer H. The fire of evolution: energy expenditure and ecology in primates and other endotherms. J Exp Biol 2023; 226:297166. [PMID: 36916459 DOI: 10.1242/jeb.245272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Total energy expenditure (TEE) represents the total energy allocated to growth, reproduction and body maintenance, as well as the energy expended on physical activity. Early experimental work in animal energetics focused on the costs of specific tasks (basal metabolic rate, locomotion, reproduction), while determination of TEE was limited to estimates from activity budgets or measurements of subjects confined to metabolic chambers. Advances in recent decades have enabled measures of TEE in free-living animals, challenging traditional additive approaches to understanding animal energy budgets. Variation in lifestyle and activity level can impact individuals' TEE on short time scales, but interspecific differences in TEE are largely shaped by evolution. Here, we review work on energy expenditure across the animal kingdom, with a particular focus on endotherms, and examine recent advances in primate energetics. Relative to other placental mammals, primates have low TEE, which may drive their slow pace of life and be an evolved response to the challenges presented by their ecologies and environments. TEE variation among hominoid primates appears to reflect adaptive shifts in energy throughput and allocation in response to ecological pressures. As the taxonomic breadth and depth of TEE data expand, we will be able to test additional hypotheses about how energy budgets are shaped by environmental pressures and explore the more proximal mechanisms that drive intra-specific variation in energy expenditure.
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Affiliation(s)
- Amanda McGrosky
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - Herman Pontzer
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA.,Duke Global Health Institute, Durham, NC 27708, USA
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7
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Kumar AV, Zimova M, Martin TE, Mills LS. Contrasting seasonal effects of climate change influence density in a cold-adapted species. GLOBAL CHANGE BIOLOGY 2022; 28:6228-6238. [PMID: 35899554 PMCID: PMC9804553 DOI: 10.1111/gcb.16352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 07/12/2022] [Indexed: 05/30/2023]
Abstract
Many ecological processes are profoundly influenced by abiotic factors, such as temperature and snow. However, despite strong evidence linking shifts in these ecological processes to corresponding shifts in abiotic factors driven by climate change, the mechanisms connecting population size to season-specific climate drivers are little understood. Using a 21-year dataset and a Bayesian state space model, we identified biologically informed seasonal climate covariates that influenced densities of snowshoe hares (Lepus americanus), a cold-adapted boreal herbivore. We found that snow and temperature had strong but conflicting season-dependent effects. Reduced snow duration in spring and fall and warmer summers were associated with lowered hare density, whereas warmer winters were associated with increased density. When modeled simultaneously and under two climate change scenarios, the negative effects of reduced fall and spring snow duration and warmer summers overwhelm the positive effect of warmer winters, producing projected population declines. Ultimately, the contrasting population-level impacts of climate change across seasons emphasize the critical need to examine the entire annual climate cycle to understand potential long-term population consequences of climate change.
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Affiliation(s)
- Alexander V. Kumar
- U.S. Fish and Wildlife ServiceFort CollinsColoradoUSA
- Wildlife Biology ProgramUniversity of MontanaMissoulaMontanaUSA
| | - Marketa Zimova
- Department of BiologyAppalachian State UniversityBooneNorth CarolinaUSA
| | - Thomas E. Martin
- U. S. Geological Survey, Montana Cooperative Wildlife Research UnitUniversity of MontanaMissoulaMontanaUSA
| | - L. Scott Mills
- Wildlife Biology ProgramUniversity of MontanaMissoulaMontanaUSA
- Wildlife Biology Program and Office of the Vice President for Research and Creative ScholarshipUniversity of MontanaMissoulaMontanaUSA
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8
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Kolbe T, Lassnig C, Poelzl A, Palme R, Auer KE, Rülicke T. Effect of Different Ambient Temperatures on Reproductive Outcome and Stress Level of Lactating Females in Two Mouse Strains. Animals (Basel) 2022; 12:ani12162141. [PMID: 36009730 PMCID: PMC9405067 DOI: 10.3390/ani12162141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 08/16/2022] [Indexed: 11/23/2022] Open
Abstract
Simple Summary The optimal temperature for laboratory mice has been under discussion for some time. Current standard temperature is 20 °C–24 °C but it has been suggested to elevate the standard to 30 °C, which is the thermoneutral zone for mice. In this study, the effect of different cage temperatures (20 °C, 25 °C, 30 °C) on reproduction and stress hormone metabolite excretion was evaluated in lactating females of two commonly used mouse strains. Pup loss was higher, and weights of mothers and pups were reduced at 30 °C compared to the lower temperatures. In addition, pups showed increased tail length at weaning under the high temperature (30 °C). There was no difference in stress hormone metabolite excretion in mice between temperature groups. We could not show any detrimental effects of the lower or higher cage temperature on stress hormone metabolite excretion, but found decreased reproductive outcome under the higher temperature. Abstract Ambient temperature is an important non-biotic environmental factor influencing immunological and oncological parameters in laboratory mice. It is under discussion which temperature is more appropriate and whether the commonly used room temperature in rodent facilities of about 21 °C represents a chronic cold stress or the 30 °C of the thermoneutral zone constitutes heat stress for the animals. In this study, we selected the physiological challenging period of lactation to investigate the influence of a cage temperature of 20 °C, 25 °C, and 30 °C, respectively, on reproductive performance and stress hormone levels in two frequently used mouse strains. We found that B6D2F1 hybrid mothers weaned more pups compared to C57BL/6N mothers, and that the number of weaned pups was reduced when mothers of both strains were kept at 30 °C. Furthermore, at 30 °C, mothers and pups showed reduced body weight at weaning and offspring had longer tails. Despite pronounced temperature effects on reproductive parameters, we did not find any temperature effects on adrenocortical activity in breeding and control mice. Independent of the ambient temperature, however, we found that females raising pups showed elevated levels of faecal corticosterone metabolites (FCMs) compared to controls. Peak levels of stress hormone metabolites were measured around birth and during the third week of lactation. Our results provide no evidence of an advantage for keeping lactating mice in ambient temperatures near the thermoneutral zone. In contrast, we found that a 30 °C cage temperature during lactation reduced body mass in females and their offspring and declined female reproductive performance.
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Affiliation(s)
- Thomas Kolbe
- Biomodels Austria, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
- Department IFA-Tulln, University of Natural Resources and Life Sciences, 1180 Vienna, Austria
- Correspondence:
| | - Caroline Lassnig
- Biomodels Austria, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Andrea Poelzl
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Kerstin E. Auer
- Institute of in vivo and in vitro Models, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Thomas Rülicke
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
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9
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Pontzer H, McGrosky A. Balancing growth, reproduction, maintenance, and activity in evolved energy economies. Curr Biol 2022; 32:R709-R719. [PMID: 35728556 DOI: 10.1016/j.cub.2022.05.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Economic models predominate in life history research, which investigates the allocation of an organism's resources to growth, reproduction, and maintenance. These approaches typically employ a heuristic Y model of resource allocation, which predicts trade-offs among tasks within a fixed budget. The common currency among tasks is not always specified, but most models imply that metabolic energy, either from food or body stores, is the critical resource. Here, we review the evidence for metabolic energy as the common currency of growth, reproduction, and maintenance, focusing on studies in humans and other vertebrates. We then discuss the flow of energy to competing physiological tasks (physical activity, maintenance, and reproduction or growth) and its effect on life history traits. We propose a Ψ model of energy flow to these tasks, which provides an integrative framework for examining the influence of environmental factors and the expansion and contraction of energy budgets in the evolution of life history strategies.
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Affiliation(s)
- Herman Pontzer
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA; Duke Global Health Institute, Duke University, Durham, NC, USA.
| | - Amanda McGrosky
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
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10
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Zagkle E, Martinez-Vidal PA, Bauchinger U, Sadowska ET. Manipulation of Heat Dissipation Capacity Affects Avian Reproductive Performance and Output. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.866182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Animal life requires hard work but the ability to endure such workload appears to be limited. Heat dissipation limit (HDL) hypothesis proposes that the capacity to dissipate the excess of body heat during hard work may limit sustained energy use. Experimental facilitations of heat loss rate via feather-clipping in free-living birds seem to support HDL hypothesis but testing of HDL through laboratory experiments under controlled conditions is not reported. We employed a two-factorial experimental design to test HDL hypothesis by manipulating the capacity to dissipate heat through exposure of captive zebra finches (Taeniopygia guttata) to a cold and warm ambient temperature (14°C and 25°C), and through manipulation of the insulating layer of feathers around the brood patch in females (clipped and unclipped). To simulate foraging costs encountered in the wild we induced foraging effort by employing a feeding system that necessitated hovering to access food, which increased energetic costs of reproduction despite ad libitum conditions in captivity. We quantified the outcome of reproductive performance at the level of both parents, females, and offspring. Thermal limitations due to warm temperature appeared at the beginning of reproduction for both parents with lower egg-laying success, smaller clutch size and lower egg mass, compared to the cold. After hatching, females with an enhanced ability to dissipate heat through feather-clipping revealed higher body mass compared to unclipped females, and these clipped females also raised heavier and bigger nestlings. Higher levels for oxidative stress in plasma of females were detected prior to reproduction in warm conditions than in the cold. However, oxidative stress biomarkers of mothers were neither affected by temperature nor by feather-clipping during the reproductive activities. We document upregulation of antioxidant capacity during reproduction that seems to prevent increased levels of oxidative stress possibly due to the cost of female body condition and offspring growth. Our study on reproduction under laboratory-controlled conditions corroborates evidence in line with the HDL hypothesis. The link between temperature-constrained sustained performance and reproductive output in terms of quality and quantity is of particular interest in light of the current climate change, and illustrates the emerging risks to avian populations.
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11
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Rolfes JW, Encarnação JA, Becker NI. Going Bald — The Hairy Affair of Timing in Telemetry Studies: Moulting Activity in European Bat Species. ACTA CHIROPTEROLOGICA 2022. [DOI: 10.3161/15081109acc2021.23.2.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Jon W. Rolfes
- Mammalian Ecology Group, Department of Animal Ecology and Systematics, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany
| | - Jorge A. Encarnação
- Mammalian Ecology Group, Department of Animal Ecology and Systematics, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany
| | - Nina I. Becker
- Institute for Applied Animal Ecology and Ecoinformatics, Im Brühl 2, 35457 Lollar, Germany
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12
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Li M, Speakman JR. Setting Ambient Temperature Conditions to Optimize Translation of Molecular Work from the Mouse to Human: The "Goldilocks Solution". Methods Mol Biol 2022; 2448:235-250. [PMID: 35167101 DOI: 10.1007/978-1-0716-2087-8_15] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Temperature has a profound effect on many aspects of murine physiology. This raises the question of the best temperature at which mice should be housed to maximize the translational potential to humans. The temperatures at which mice have been routinely kept for studies of molecular physiology (20-21 °C) maximize the comfort of animal handling staff. There is a widespread movement suggesting we should perform experiments instead on mice housed at 30 °C. This often produces very different outcomes. Here we analyze the basis of this suggestion and show that while 20-21 °C is too cold, 30 °C is probably too hot. Rather we suggest an intermediate temperature "the Goldilocks solution" of 25-26 °C is probably optimal. This should be combined with providing animals with nesting material so that they can construct nests to generate microclimates that are within their own control. Providing copious nesting material has additional spin-off advantages in terms of increasing environmental enrichment. Ultimately, however, advocating a single temperature to mimic human physiology is plagued by the problem that humans vary widely in the temperature environments they experience, with consequences for human disease. Hence studying responses at a range of temperatures may provide the greatest insights and translational potential.
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Affiliation(s)
- Min Li
- Shenzhen Key Laboratory for Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen, Institutes of Advanced Technology, Shenzhen, China
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of the Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Aberdeen, Scotland, UK
| | - John R Speakman
- Shenzhen Key Laboratory for Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen, Institutes of Advanced Technology, Shenzhen, China.
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
- University of the Chinese Academy of Sciences, Beijing, China.
- School of Biological Sciences, University of Aberdeen, Scotland, UK.
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13
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Huang YX, Li HH, Wang L, Min HX, Xu JQ, Wu SL, Cao J, Zhao ZJ. The Ability to Dissipate Heat Is Likely to Be a More Important Limitation on Lactation in Striped Hamsters with Greater Reproductive Efforts under Warmer Conditions. Physiol Biochem Zool 2021; 93:282-295. [PMID: 32484722 DOI: 10.1086/709538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The limitations on energy availability and outputs have been implied to have a profound effect on the evolution of many morphological and behavioral traits. It has been suggested that the reproductive performance of mammals is frequently constrained by intrinsic physiological factors, such as the capacity of the mammary glands to produce milk (the peripheral limitation [PL] hypothesis) or that of the body to dissipate heat (the heat dissipation limitation [HDL] hypothesis). Research on a variety of small mammals, however, has so far failed to provide unequivocal support for one hypothesis over the other. We tested the PL and HDL hypotheses in female striped hamsters (Cricetulus barabensis) with artificially manipulated litter sizes of two (three or four pups removed from natural litter size), five, eight (two or three pups added to natural litter size), and 12 (five to seven pups added to natural litter size) pups at ambient temperatures of 21° and 30°C. Energy intake and milk output of mothers, litter size, and litter mass were measured throughout lactation. Several markers indicating digestive enzyme activity and the gene expression of hypothalamic neuropeptides related to food intake were also measured. Food consumption and milk output increased with increasing litter size but reached a ceiling at 12 pups, causing 12-pup litters to have significantly lower litter mass and pup body mass than litters composed of fewer pups. Litter mass and maternal metabolic rate, milk output, maltase, sucrase, and aminopeptidase activity in the small intestine, and gene expression of hypothalamic orexigenic peptides were significantly lower at 30°C than at 21°C, and these differences were considerably more pronounced in 12-pup litters. These results suggest that PL and HDL can operate simultaneously but that the HDL hypothesis is probably more valid at warmer temperatures. Our results suggest that increased environmental temperatures in future climates may limit reproductive output through heat dissipation limits.
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14
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Ohrnberger SA, Hambly C, Speakman JR, Valencak TG. Limits to sustained energy intake. XXXII. Hot again: dorsal shaving increases energy intake and milk output in golden hamsters ( Mesocricetus auratus). J Exp Biol 2020; 223:jeb230383. [PMID: 33188060 DOI: 10.1242/jeb.230383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 11/09/2020] [Indexed: 12/16/2022]
Abstract
Golden hamsters have four times the body size of mice, raise very large litters and are required to produce large quantities of milk during the 18-day lactation period. We have previously proposed that they may be prone to being limited by their heat dissipation capacity. Studies where lactating females are shaved to elevate their heat dissipation capacity have yielded conflicting data so far. With their short pregnancy of ∼18 days, the large litters and the reported high skin temperatures, they may serve as an ideal model to elucidate the role of epilation for energy budgets in lactating mammals. We shaved one group of lactating females dorsally on the sixth day of lactation, and tested if the elevated heat dissipation capacity would enable them to have higher energy intakes and better food-to-milk conversion rates. Indeed, we observed that females from the shaved group had 6% higher body mass and 0.78°C lower skin temperature than control females during lactation. When focusing on the phase of peak lactation, we observed significantly higher (10%) gross energy intake of food and 23.4% more milk energy output in the shaved females, resulting in 3.3 g higher individual pup weights. We conclude that shaving off the females' fur, even though restricted to the dorsal surface, had large consequences on female energy metabolism in lactation and improved milk production and pup growth in line with our previous work on heat dissipation limitation. Our new data from golden hamsters confirm heat dissipation as a limiting factor for sustained metabolic rate in lactation in some small mammals and emphasise the large effects of a relatively small manipulation such as fur removal on energy metabolism of lactating females.
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Affiliation(s)
- S A Ohrnberger
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
| | - C Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - J R Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
- Institute of Genetics and Developmental Biology, State Key Laboratory of Molecular Developmental Biology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
- CAS Center of Excellence in Animal Evolution and Genetics, Kunming 650223, China
| | - T G Valencak
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
- College of Animal Sciences, Zhejiang University, Zijingang Campus, 866 Yuhangtang Road, 310058 Hangzhou, People's Republic of China
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15
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Kozłowski J, Konarzewski M, Czarnoleski M. Coevolution of body size and metabolic rate in vertebrates: a life-history perspective. Biol Rev Camb Philos Soc 2020; 95:1393-1417. [PMID: 32524739 PMCID: PMC7540708 DOI: 10.1111/brv.12615] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 05/05/2020] [Accepted: 05/07/2020] [Indexed: 12/30/2022]
Abstract
Despite many decades of research, the allometric scaling of metabolic rates (MRs) remains poorly understood. Here, we argue that scaling exponents of these allometries do not themselves mirror one universal law of nature but instead statistically approximate the non-linearity of the relationship between MR and body mass. This 'statistical' view must be replaced with the life-history perspective that 'allows' organisms to evolve myriad different life strategies with distinct physiological features. We posit that the hypoallometric allometry of MRs (mass scaling with an exponent smaller than 1) is an indirect outcome of the selective pressure of ecological mortality on allocation 'decisions' that divide resources among growth, reproduction, and the basic metabolic costs of repair and maintenance reflected in the standard or basal metabolic rate (SMR or BMR), which are customarily subjected to allometric analyses. Those 'decisions' form a wealth of life-history variation that can be defined based on the axis dictated by ecological mortality and the axis governed by the efficiency of energy use. We link this variation as well as hypoallometric scaling to the mechanistic determinants of MR, such as metabolically inert component proportions, internal organ relative size and activity, cell size and cell membrane composition, and muscle contributions to dramatic metabolic shifts between the resting and active states. The multitude of mechanisms determining MR leads us to conclude that the quest for a single-cause explanation of the mass scaling of MRs is futile. We argue that an explanation based on the theory of life-history evolution is the best way forward.
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Affiliation(s)
- Jan Kozłowski
- Institute of Environmental SciencesJagiellonian UniversityGronostajowa7, 30‐387KrakówPoland
| | - Marek Konarzewski
- Institute of BiologyUniversity of BiałystokCiołkowskiego 1J, 15‐245, BiałystokPoland
| | - Marcin Czarnoleski
- Institute of Environmental SciencesJagiellonian UniversityGronostajowa7, 30‐387KrakówPoland
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16
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Late lactation in small mammals is a critically sensitive window of vulnerability to elevated ambient temperature. Proc Natl Acad Sci U S A 2020; 117:24352-24358. [PMID: 32929014 DOI: 10.1073/pnas.2008974117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Predicted increases in global average temperature are physiologically trivial for most endotherms. However, heat waves will also increase in both frequency and severity, and these will be physiologically more important. Lactating small mammals are hypothesized to be limited by heat dissipation capacity, suggesting high temperatures may adversely impact lactation performance. We measured reproductive performance of mice and striped hamsters (Cricetulus barabensis), including milk energy output (MEO), at temperatures between 21 and 36 °C. In both species, there was a decline in MEO between 21 and 33 °C. In mice, milk production at 33 °C was only 18% of that at 21 °C. This led to reductions in pup growth by 20% but limited pup mortality (0.8%), because of a threefold increase in growth efficiency. In contrast, in hamsters, MEO at 33 °C was reduced to 78.1% of that at 21 °C, yet this led to significant pup mortality (possibly infanticide) and reduced pup growth by 12.7%. Hamster females were more able to sustain milk production as ambient temperature increased, but they and their pups were less capable of adjusting to the lower supply. In both species, exposure to 36 °C resulted in rapid catastrophic lactation failure and maternal mortality. Upper lethal temperature was lowered by 3 to 6 °C in late lactation, making it a critically sensitive window to high ambient temperatures. Our data suggest future heat wave events will impact breeding success of small rodents, but this is based on animals with a long history in captivity. More work should be performed on wild rodents to confirm these impacts.
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17
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Yu JX, Deng GM, Xu JQ, Cao J, Zhao ZJ. The energy budget and fat accumulation in striped hamsters (Cricetulus barabensis) during post-lactation. Comp Biochem Physiol A Mol Integr Physiol 2020; 249:110755. [PMID: 32673739 DOI: 10.1016/j.cbpa.2020.110755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/05/2020] [Accepted: 07/06/2020] [Indexed: 12/23/2022]
Abstract
Adaptive adjustments of energy intake and body fat play an important role in allowing animals' to meet the energy demands of thermoregulation during cold conditions and reproduction. Body fat is usually metabolized during lactation, which is one of the most energetically demanding activities of female mammals, however the effect of this on the energy budget and body fat regulation after lactation remains unclear. We compared the energy intake and body fat of female striped hamsters (Cricetulus barabensis) fed either a high-fat or low-fat diet for 21 days after the end of lactation (post-lactation, PL) to those of virgin controls. Serum leptin levels and the expression of hypothalamic orexigenic and anorexigenic neuropeptide genes were also measured and compared. Although lactating females consumed significantly more food, they had significantly lower body fat than virgin controls. The energy intake and body fat levels of the PL females were, however, significantly higher than those of virgin females. This was particularly true for the PL females that were fed high-fat diet. These females had significantly higher serum leptin concentrations, but lower hypothalamic leptin receptor gene expression, than virgin females. Neither orexigenic nor anorexigenic neuropeptide levels in the hypothalamus differed significantly between the PL and virgin females. This suggests that a negative energy balance during lactation drives fat accumulation after lactation. Furthermore, leptin resistance may occur after the end of lactation, causing females to consume more food, and accumulate more fat, than virgin females.
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Affiliation(s)
- Jing-Xin Yu
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Guang-Min Deng
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Jia-Qi Xu
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Jing Cao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Zhi-Jun Zhao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China.
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18
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Tapper S, Nocera JJ, Burness G. Heat dissipation capacity influences reproductive performance in an aerial insectivore. J Exp Biol 2020; 223:jeb222232. [PMID: 32321750 DOI: 10.1242/jeb.222232] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/08/2020] [Indexed: 12/26/2022]
Abstract
Climatic warming is predicted to increase the frequency of extreme weather events, which may reduce an individual's capacity for sustained activity because of thermal limits. We tested whether the risk of overheating may limit parental provisioning of an aerial insectivorous bird in population decline. For many seasonally breeding birds, parents are thought to operate close to an energetic ceiling during the 2-3 week chick-rearing period. The factors determining the ceiling remain unknown, although it may be set by an individual's capacity to dissipate body heat (the heat dissipation limitation hypothesis). Over two breeding seasons we experimentally trimmed the ventral feathers of female tree swallows (Tachycineta bicolor) to provide a thermal window. We then monitored maternal and paternal provisioning rates, nestling growth rates and fledging success. We found the effect of our experimental treatment was context dependent. Females with an enhanced capacity to dissipate heat fed their nestlings at higher rates than controls when conditions were hot, but the reverse was true under cool conditions. Control females and their mates both reduced foraging under hot conditions. In contrast, male partners of trimmed females maintained a constant feeding rate across temperatures, suggesting attempts to match the feeding rate of their partners. On average, nestlings of trimmed females were heavier than controls, but did not have a higher probability of fledging. We suggest that removal of a thermal constraint allowed females to increase provisioning rates, but additionally provided nestlings with a thermal advantage via increased heat transfer during maternal brooding. Our data provide support for the heat dissipation limitation hypothesis and suggest that depending on temperature, heat dissipation capacity can influence reproductive success in aerial insectivores.
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Affiliation(s)
- Simon Tapper
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, Canada, K9L 0G2
| | - Joseph J Nocera
- University of New Brunswick, Forestry and Environmental Management, Fredericton, NB, Canada, E3B 5A3
| | - Gary Burness
- Department of Biology, Trent University, Trent University, 1600 West Bank Drive, Peterborough, ON, Canada, K9L 0G2
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19
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Huang Y, Mendoza JO, Hambly C, Li B, Jin Z, Li L, Madizi M, Hu S, Speakman JR. Limits to sustained energy intake. XXXI. Effect of graded levels of dietary fat on lactation performance in Swiss mice. J Exp Biol 2020; 223:jeb221911. [PMID: 32291324 DOI: 10.1242/jeb.221911] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 04/04/2020] [Indexed: 08/26/2023]
Abstract
The heat dissipation limit theory predicts that lactating female mice consuming diets with lower specific dynamic action (SDA) should have enhanced lactation performance. Dietary fat has lower SDA than other macronutrients. Here we tested the effects of graded dietary fat levels on lactating Swiss mice. We fed females five diets varying in fat content from 8.3 to 66.6%. Offspring of mothers fed diets of 41.7% fat and above were heavier and fatter at weaning compared with those of 8.3 and 25% fat diets. Mice on dietary fat contents of 41.7% and above had greater metabolizable energy intake at peak lactation (8.3%: 229.4±39.6; 25%: 278.8±25.8; 41.7%: 359.6±51.5; 58.3%: 353.7±43.6; 66.6%: 346±44.7 kJ day-1), lower daily energy expenditure (8.3%: 128.5±16; 25%: 131.6±8.4; 41.7%: 124.4±10.8; 58.3%: 115.1±10.5; 66.6%: 111.2±11.5 kJ day-1) and thus delivered more milk energy to their offspring (8.3%: 100.8±27.3; 25%: 147.2±25.1; 41.7%: 225.1±49.6; 58.3%: 238.6±40.1; 66.6%: 234.8±41.1 kJ day-1). Milk fat content (%) was unrelated to dietary fat content, indicating that females on higher fat diets (>41.7%) produced more rather than richer milk. Mothers consuming diets with 41.7% fat or above enhanced their lactation performance compared with those on 25% or less, probably by diverting dietary fat directly into the milk, thereby avoiding the costs of lipogenesis. At dietary fat contents above 41.7% they were either unable to transfer more dietary fat to the milk, or they chose not to do so, potentially because of a lack of benefit to the offspring that were increasingly fatter as maternal dietary fat increased.
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Affiliation(s)
- Yi Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | | | - Catherine Hambly
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - Baoguo Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
| | - Zengguang Jin
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- School of Basic Medical Science, Dali University, Dali, Yunnan 671000, China
| | - Li Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
| | - Moshen Madizi
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China
| | - Sumei Hu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - John R Speakman
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
- CAS Center for Excellence in Animal Evolution and Genetics, Kunming, Yunnan 650223, China
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20
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Zhao ZJ, Derous D, Gerrard A, Wen J, Liu X, Tan S, Hambly C, Speakman JR. Limits to sustained energy intake. XXX. Constraint or restraint? Manipulations of food supply show peak food intake in lactation is constrained. J Exp Biol 2020; 223:jeb208314. [PMID: 32139473 DOI: 10.1242/jeb.208314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 02/27/2020] [Indexed: 11/20/2022]
Abstract
Lactating mice increase food intake 4- to 5-fold, reaching an asymptote in late lactation. A key question is whether this asymptote reflects a physiological constraint, or a maternal investment strategy (a 'restraint'). We exposed lactating mice to periods of food restriction, hypothesizing that if the limit reflected restraint, they would compensate by breaching the asymptote when refeeding. In contrast, if it was a constraint, they would by definition be unable to increase their intake on refeeding days. Using isotope methods, we found that during food restriction, the females shut down milk production, impacting offspring growth. During refeeding, food intake and milk production rose again, but not significantly above unrestricted controls. These data provide strong evidence that asymptotic intake in lactation reflects a physiological/physical constraint, rather than restraint. Because hypothalamic neuropeptide Y (Npy) was upregulated under both states of restriction, this suggests the constraint is not imposed by limits in the capacity to upregulate hunger signalling (the saturated neural capacity hypothesis). Understanding the genetic basis of the constraint will be a key future goal and will provide us additional information on the nature of the constraining factors on reproductive output, and their potential links to life history strategies.
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Affiliation(s)
- Zhi-Jun Zhao
- School of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang 325035, China
| | - Davina Derous
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - Abby Gerrard
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100100, China
| | - Jing Wen
- School of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang 325035, China
| | - Xue Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100100, China
| | - Song Tan
- School of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang 325035, China
| | - Catherine Hambly
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - John R Speakman
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100100, China
- CAS Center of Excellence for Animal Evolution and Genetics, Kunming 650223, China
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21
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Bao MH, Chen LB, Hambly C, Speakman JR, Zhao ZJ. Exposure to hot temperatures during lactation stunted offspring growth and decreased the future reproductive performance of female offspring. J Exp Biol 2020:jeb.223560. [PMID: 34005557 DOI: 10.1242/jeb.223560] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 03/31/2020] [Indexed: 12/15/2022]
Abstract
Among the important aspects of climate change, exposure to high temperatures (heat waves) is rapidly emerging as an important issue, in particular for female mammals during lactation. High temperatures adversely impact ability to dissipate heat, which has negative effects on reproductive output. The cumulative effects on growth of F1 offspring after weaning and future reproductive performance of offspring remain uncertain. In this study, the F1 mice that weaned from mothers lactating at 21°C and 32.5°C were housed at 21°C from day 19 till 56 of age; during which food intake and body mass were measured. The F1 adult females that had been weaned at the two temperatures were bred and then both exposed to 32.5°C during lactation. Energy intake, milk output and litter size and mass were determined. The F1 adults weaned at 32.5°C consumed less food and had lower body mass than their counterparts weaned at 21°C. Several visceral organs or reproductive tissues were significantly lower in mass in F1 weaned at 32.5°C than at 21°C. The exposure to 32.5°C significantly decreased energy intake, milk output and litter mass in F1 adult females during lactation. The F1 adult females weaned at 32.5°C produced less milk and raised lighter pups than those previously weaned at 21°C. The data suggest that transient exposure to hot temperature during lactation has long-lasting impacts on the offspring, including stunted growth and decreases in future reproductive performance when adult. This indicates that the offspring of females previously experiencing hot temperatures have a significant fitness disadvantage.
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Affiliation(s)
- Meng-Huan Bao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Li-Bing Chen
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Catherine Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - John R Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
- State Key Laboratory of Molecular Developmental Biology, Chinese Academy of Sciences, Bei Chen Xi Lu, Chaoyang, Beijing 100101, People's Republic of China
- CAS Center of Excellence in Animal Evolution and Genetics, Kunming, People's Republic of China
| | - Zhi-Jun Zhao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
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22
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Andreasson F, Hegemann A, Nord A, Nilsson JÅ. Experimental facilitation of heat loss affects work rate and innate immune function in a breeding passerine bird. J Exp Biol 2020; 223:jeb.219790. [DOI: 10.1242/jeb.219790] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 03/11/2020] [Indexed: 01/06/2023]
Abstract
The capacity to get rid of excess heat produced during hard work is a possible constraint on parental effort during reproduction (heat dissipation limit [HDL] theory). We released hard-working blue tits (Cyanistes caeruleus) from this constraint by experimentally removing ventral plumage. We then assessed if this changed their reproductive effort (feeding rate and nestling size) and levels of self-maintenance (change in body mass and innate immune function). Feather-clipped females reduced the number of feeding visits and increased levels of constitutive innate immunity compared to unclipped females but did not fledge smaller nestlings. Thus, they increased self-maintenance without compromising current reproductive output. In contrast, feather-clipping did not affect the number of feeding visits or innate immune function in males, despite increased heat loss rate. Our results show that analyses of physiological parameters, such as constitutive innate immune function, can be important when trying to understand sources of variation in investment in self-maintenance versus reproductive effort and that risk of overheating can influence innate immune function during reproduction.
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Affiliation(s)
- Fredrik Andreasson
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
| | - Arne Hegemann
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
| | - Andreas Nord
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
- Scottish Centre for Ecology and the Natural Environment, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Rowardennan G63 0AW, UK
| | - Jan-Åke Nilsson
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
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23
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Nomano FY, Savage JL, Browning LE, Griffith SC, Russell AF. Breeding Phenology and Meteorological Conditions Affect Carer Provisioning Rates and Group-Level Coordination in Cooperative Chestnut-Crowned Babblers. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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24
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Switching off the furnace: brown adipose tissue and lactation. Mol Aspects Med 2019; 68:18-41. [DOI: 10.1016/j.mam.2019.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 06/12/2019] [Indexed: 12/31/2022]
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25
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Fifty shades of brown: The functions, diverse regulation and evolution of brown adipose tissue. Mol Aspects Med 2019; 68:1-5. [PMID: 31325457 DOI: 10.1016/j.mam.2019.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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26
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Thurber C, Dugas LR, Ocobock C, Carlson B, Speakman JR, Pontzer H. Extreme events reveal an alimentary limit on sustained maximal human energy expenditure. SCIENCE ADVANCES 2019; 5:eaaw0341. [PMID: 31183404 PMCID: PMC6551185 DOI: 10.1126/sciadv.aaw0341] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 04/30/2019] [Indexed: 06/09/2023]
Abstract
The limits on maximum sustained energy expenditure are unclear but are of interest because they constrain reproduction, thermoregulation, and physical activity. Here, we show that sustained expenditure in humans, measured as maximum sustained metabolic scope (SusMS), is a function of event duration. We compiled measurements of total energy expenditure (TEE) and basal metabolic rate (BMR) from human endurance events and added new data from adults running ~250 km/week for 20 weeks in a transcontinental race. For events lasting 0.5 to 250+ days, SusMS decreases curvilinearly with event duration, plateauing below 3× BMR. This relationship differs from that of shorter events (e.g., marathons). Incorporating data from overfeeding studies, we find evidence for an alimentary energy supply limit in humans of ~2.5× BMR; greater expenditure requires drawing down the body's energy stores. Transcontinental race data suggest that humans can partially reduce TEE during long events to extend endurance.
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Affiliation(s)
- Caitlin Thurber
- Department of Anthropology, Hunter College, New York, NY 10065, USA
| | - Lara R. Dugas
- Public Health Sciences, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
| | - Cara Ocobock
- Department of Anthropology, University at Albany, SUNY, Albany, NY 12222, USA
| | - Bryce Carlson
- Department of Anthropology, Purdue University, West Lafayette, IN 47907, USA
| | - John R. Speakman
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Scotland, UK
| | - Herman Pontzer
- Department of Anthropology, Hunter College, New York, NY 10065, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27710, USA
- Duke Global Health Institute, Duke University, Durham, NC 27710, USA
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Keijer J, Li M, Speakman JR. What is the best housing temperature to translate mouse experiments to humans? Mol Metab 2019; 25:168-176. [PMID: 31003945 PMCID: PMC6599456 DOI: 10.1016/j.molmet.2019.04.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 04/01/2019] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES Ambient temperature impinges on energy metabolism in a body size dependent manner. This has implications for the housing temperature at which mice are best compared to humans. In 2013, we suggested that, for comparative studies, solitary mice are best housed at 23-25 °C, because this is 3-5 °C below the mouse thermoneutral zone and humans routinely live 3-5 °C below thermoneutrality, and because this generates a ratio of DEE to BMR of 1.6-1.9, mimicking the ratio found in free-living humans. METHODS Recently, Fischer et al. (2017) challenged this estimate. By studying mice at 21 °C and at 30 °C (but notably not at 23-25 °C) they concluded that 30 °C is the optimal housing temperature. Here, we measured energy metabolism of C57BL/6 mice over a range of temperatures, between 21.4 °C and 30.2 °C. RESULTS We observed a ratio of DEE to BMR of 1.7 at 27.6 °C and of 1.8 at 25.5 °C, suggesting that this is the best temperature range for housing C57BL/6 mice to mimic human thermal relations. We used a 24 min average to calculate the ratio, similar to that used in human studies, while the ratio calculated by Fisher et al. dependent on short, transient metabolic declines. CONCLUSION We concur with Fisher et al. and others that 21 °C is too cool, but we continue to suggest that 30 °C is too warm. We support this with other data. Finally, to mimic living environments of all humans, and not just those in controlled Western environments, mouse experimentation at various temperatures is likely required.
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Affiliation(s)
- Jaap Keijer
- Human and Animal Physiology, Wageningen University, De Elst 1, PO box 338, 6700 AH, Wageningen, the Netherlands.
| | - Min Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - John R Speakman
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, UK; CAS Centre of Excellence in Animal Evolution and Genetics, Kunming, China.
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28
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Nilsson JÅ, Nord A. Testing the heat dissipation limit theory in a breeding passerine. Proc Biol Sci 2019; 285:rspb.2018.0652. [PMID: 29769365 DOI: 10.1098/rspb.2018.0652] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 04/19/2018] [Indexed: 11/12/2022] Open
Abstract
The maximum work rate of animals has recently been suggested to be determined by the rate at which excess metabolic heat generated during work can be dissipated (heat dissipation limitation (HDL) theory). As a first step towards testing this theory in wild animals, we experimentally manipulated brood size in breeding marsh tits (Poecile palustris) to change their work rate. Parents feeding nestlings generally operated at above-normal body temperatures. Body temperature in both males and females increased with maximum ambient temperature and with manipulated work rate, sometimes even exceeding 45°C, which is close to suggested lethal levels for birds. Such high body temperatures have previously only been described for birds living in hot and arid regions. Thus, reproductive effort in marsh tits may potentially be limited by the rate of heat dissipation. Females had lower body temperatures, a possible consequence of their brood patch serving as a thermal window facilitating heat dissipation. Because increasing body temperatures are connected to somatic costs, we suggest that the HDL theory may constitute a possible mediator of the trade-off between current and future reproduction. It follows that globally increasing, more stochastic, ambient temperatures may restrict the capacity for sustained work of animals in the future.
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Affiliation(s)
- Jan-Åke Nilsson
- Department of Biology, Section of Evolutionary Ecology, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Andreas Nord
- Department of Biology, Section of Evolutionary Ecology, Lund University, Ecology Building, 223 62 Lund, Sweden
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Sadowska J, Gębczyński AK, Lewoc M, Konarzewski M. Not that hot after all: no limits to heat dissipation in lactating mice selected for high or low BMR. J Exp Biol 2019; 222:jeb.204669. [DOI: 10.1242/jeb.204669] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 08/09/2019] [Indexed: 01/06/2023]
Abstract
Heat dissipation has been suggested as a limit to sustained metabolic effort, e.g. during lactation, when overheating is a possible risk. We tested this hypothesis using mice artificially selected for high (H-BMR) or low (L-BMR) BMR that also differ with respect to parental effort. We used fixed sized cross-fostered families and recorded litter mass daily until the 14th day of lactation. Midway through the experiment (day 8th) half of randomly chosen mothers from each line type had fur from the dorsal body surface removed to increase their thermal conductance and facilitate heat dissipation. Our results showed that neither of the line types benefited from increasing their thermal conductance at peak lactation. On the contrary, growth of the litters reared by the L-BMR females was compromised. Thus, our results do not support the heat dissipation limitation hypothesis.
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Affiliation(s)
- Julita Sadowska
- Institute of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland
| | - Andrzej K. Gębczyński
- Institute of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland
| | - Małgorzata Lewoc
- Institute of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland
| | - Marek Konarzewski
- Institute of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland
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30
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Affiliation(s)
- Andreas Nord
- Department of Biology, Section for Evolutionary Ecology, Ecology Building Lund University Lund Sweden
| | - Jan‐Åke Nilsson
- Department of Biology, Section for Evolutionary Ecology, Ecology Building Lund University Lund Sweden
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31
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Nilaweera KN, Speakman JR. Regulation of intestinal growth in response to variations in energy supply and demand. Obes Rev 2018; 19 Suppl 1:61-72. [PMID: 30511508 PMCID: PMC6334514 DOI: 10.1111/obr.12780] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 09/11/2018] [Indexed: 12/14/2022]
Abstract
The growth of the intestine requires energy, which is known to be met by catabolism of ingested nutrients. Paradoxically, during whole body energy deficit including calorie restriction, the intestine grows in size. To understand how and why this happens, we reviewed data from several animal models of energetic challenge. These were bariatric surgery, cold exposure, lactation, dietary whey protein intake and calorie restriction. Notably, these challenges all reduced the adipose tissue mass, altered hypothalamic neuropeptide expression and increased intestinal size. Based on these data, we propose that the loss of energy in the adipose tissue promotes the growth of the intestine via a signalling mechanism involving the hypothalamus. We discuss possible candidates in this pathway including data showing a correlative change in intestinal (ileal) expression of the cyclin D1 gene with adipose tissue mass, adipose derived-hormone leptin and hypothalamic expression of leptin receptor and the pro-opiomelanocortin gene. The ability of the intestine to grow in size during depletion of energy stores provides a mechanism to maximize assimilation of ingested energy and in turn sustain critical functions of tissues important for survival.
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Affiliation(s)
- K N Nilaweera
- Department of Food Biosciences, Teagasc Food Research Centre, Fermoy, County Cork, Ireland
| | - J R Speakman
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
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32
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Khaliq I, Hof C. Testing the heat dissipation limitation hypothesis: basal metabolic rates of endotherms decrease with increasing upper and lower critical temperatures. PeerJ 2018; 6:e5725. [PMID: 30402344 PMCID: PMC6215442 DOI: 10.7717/peerj.5725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/05/2018] [Indexed: 12/12/2022] Open
Abstract
Metabolic critical temperatures define the range of ambient temperatures where endotherms are able to minimize energy allocation to thermogenesis. Examining the relationship between metabolic critical temperatures and basal metabolic rates (BMR) provides a unique opportunity to gain a better understanding of how animals respond to varying ambient climatic conditions, especially in times of ongoing and projected future climate change. We make use of this opportunity by testing the heat dissipation limit (HDL) theory, which hypothesizes that the maximum amount of heat a species can dissipate constrains its energetics. Specifically, we test the theory’s implicit prediction that BMR should be lower under higher metabolic critical temperatures. We analysed the relationship of BMR with upper and lower critical temperatures for a large dataset of 146 endotherm species using regression analyses, carefully accounting for phylogenetic relationships and body mass. We show that metabolic critical temperatures are negatively related with BMR in both birds and mammals. Our results confirm the predictions of the HDL theory, suggesting that metabolic critical temperatures and basal metabolic rates respond in concert to ambient climatic conditions. This implies that heat dissipation capacities of endotherms may be an important factor to take into account in assessments of species’ vulnerability to climate change.
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Affiliation(s)
- Imran Khaliq
- Department of Zoology, Ghazi University, Pakistan, Dera Ghazi Khan, Punjab, Pakistan.,Senckenberg Biodiversity and Climate Research Centre (BiK-F), Frankfurt, Germany.,Institute for Ecology, Evolution and Diversity, Department of Biological Sciences, Johann Wolfgang Goethe Universität Frankfurt am Main, Frankfurt, Germany
| | - Christian Hof
- Senckenberg Biodiversity and Climate Research Centre (BiK-F), Frankfurt, Germany.,Terrestrial Ecology Research Group, Department for Ecology and Ecosystem Management, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
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33
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Harrison JF. Approaches for testing hypotheses for the hypometric scaling of aerobic metabolic rate in animals. Am J Physiol Regul Integr Comp Physiol 2018; 315:R879-R894. [DOI: 10.1152/ajpregu.00165.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypometric scaling of aerobic metabolism [larger organisms have lower mass-specific metabolic rates (MR/g)] is nearly universal for interspecific comparisons among animals, yet we lack an agreed upon explanation for this pattern. If physiological constraints on the function of larger animals occur and limit MR/g, these should be observable as direct constraints on animals of extant species and/or as evolved responses to compensate for the proposed constraint. There is evidence for direct constraints and compensatory responses to O2 supply constraint in skin-breathing animals, but not in vertebrates with gas-exchange organs. The duration of food retention in the gut is longer for larger birds and mammals, consistent with a direct constraint on nutrient uptake across the gut wall, but there is little evidence for evolving compensatory responses to gut transport constraints in larger animals. Larger placental mammals (but not marsupials or birds) show evidence of greater challenges with heat dissipation, but there is little evidence for compensatory adaptations to enhance heat loss in larger endotherms, suggesting that metabolic rate (MR) more generally balances heat loss for thermoregulation in endotherms. Size-dependent patterns in many molecular, physiological, and morphological properties are consistent with size-dependent natural selection, such as stronger selection for neurolocomotor performance and growth rate in smaller animals and stronger selection for safety and longevity in larger animals. Hypometric scaling of MR very likely arises from different mechanisms in different taxa and conditions, consistent with the diversity of scaling slopes for MR.
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Affiliation(s)
- Jon F. Harrison
- School of Life Sciences, Arizona State University, Tempe, Arizona
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34
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Vaanholt LM, Duah OA, Balduci S, Mitchell SE, Hambly C, Speakman JR. Limits to sustained energy intake. XXVII. Trade-offs between first and second litters in lactating mice support the ecological context hypothesis. ACTA ACUST UNITED AC 2018; 221:jeb.170902. [PMID: 29361590 DOI: 10.1242/jeb.170902] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 12/27/2017] [Indexed: 12/18/2022]
Abstract
Increased reproductive effort may lead to trade-offs with future performance and impact offspring, thereby influencing optimal current effort level. We experimentally enlarged or reduced litter size in mice during their first lactation, and then followed them through a successive unmanipulated lactation. Measurements of food intake, body mass, milk energy output (MEO), litter size and litter mass were taken. Offspring from the first lactation were also bred to investigate their reproductive success. In their first lactation, mothers with enlarged litters (n=9, 16 pups) weaned significantly smaller pups, culled more pups, and increased MEO and food intake compared with mothers with reduced litters (n=9, 5 pups). In the second lactation, no significant differences in pup mass or litter size were observed between groups, but mothers that had previously reared enlarged litters significantly decreased pup mass, MEO and food intake compared with those that had reared reduced litters. Female offspring from enlarged litters weaned slightly smaller pups than those from reduced litters, but displayed no significant differences in any of the other variables measured. These results suggest that females with enlarged litters suffered from a greater energetic burden during their first lactation, and this was associated with lowered performance in a successive reproductive event and impacted on their offspring's reproductive performance. Female 'choice' about how much to invest in the first lactation may thus be driven by trade-offs with future reproductive success. Hence, the 'limit' on performance may not be a hard physiological limit. These data support the ecological context hypothesis.
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Affiliation(s)
- Lobke M Vaanholt
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - Osei A Duah
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - Suzanna Balduci
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - Sharon E Mitchell
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - Catherine Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - John R Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK .,Institute of Genetics and Developmental Biology, State Key Laboratory of Molecular Developmental Biology, Chinese Academy of Sciences, Beijing, People's Republic of China
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35
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Abstract
Human obesity has a large genetic component, yet has many serious negative consequences. How this state of affairs has evolved has generated wide debate. The thrifty gene hypothesis was the first attempt to explain obesity as a consequence of adaptive responses to an ancient environment that in modern society become disadvantageous. The idea is that genes (or more precisely, alleles) predisposing to obesity may have been selected for by repeated exposure to famines. However, this idea has many flaws: for instance, selection of the supposed magnitude over the duration of human evolution would fix any thrifty alleles (famines kill the old and young, not the obese) and there is no evidence that hunter-gatherer populations become obese between famines. An alternative idea (called thrifty late) is that selection in famines has only happened since the agricultural revolution. However, this is inconsistent with the absence of strong signatures of selection at single nucleotide polymorphisms linked to obesity. In parallel to discussions about the origin of obesity, there has been much debate regarding the regulation of body weight. There are three basic models: the set-point, settling point and dual-intervention point models. Selection might act against low and high levels of adiposity because food unpredictability and the risk of starvation selects against low adiposity whereas the risk of predation selects against high adiposity. Although evidence for the latter is quite strong, evidence for the former is relatively weak. The release from predation ∼2-million years ago is suggested to have led to the upper intervention point drifting in evolutionary time, leading to the modern distribution of obesity: the drifty gene hypothesis. Recent critiques of the dual-intervention point/drifty gene idea are flawed and inconsistent with known aspects of energy balance physiology. Here, I present a new formulation of the dual-intervention point model. This model includes the novel suggestion that food unpredictability and starvation are insignificant factors driving fat storage, and that the main force driving up fat storage is the risk of disease and the need to survive periods of pathogen-induced anorexia. This model shows why two independent intervention points are more likely to evolve than a single set point. The molecular basis of the lower intervention point is likely based around the leptin pathway signalling. Determining the molecular basis of the upper intervention point is a crucial key target for future obesity research. A potential definitive test to separate the different models is also described.
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Affiliation(s)
- John R Speakman
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China .,Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, UK
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36
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Ohrnberger SA, Brinkmann K, Palme R, Valencak TG. Dorsal shaving affects concentrations of faecal cortisol metabolites in lactating golden hamsters. Naturwissenschaften 2018; 105:13. [PMID: 29335818 PMCID: PMC5769818 DOI: 10.1007/s00114-017-1536-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 12/20/2017] [Accepted: 12/22/2017] [Indexed: 11/04/2022]
Abstract
Breeding of golden hamsters is classically performed at thermal conditions ranging from 20 to 24 °C. However, growing evidence suggests that lactating females suffer from heat stress. We hypothesised that shaving females dorsally to maximise heat dissipation may reduce stress during reproduction. We thus compared faecal cortisol metabolites (FCM) from shaved golden hamster mothers with those from unshaved controls. We observed significantly lower FCM levels in the shaved mothers (F1,22 = 8.69, p = 0.0075) pointing to lower stress due to ameliorated heat dissipation over the body surface. In addition, we observed 0.4 °C lower mean subcutaneous body temperatures in the shaved females, although this effect did not reach significance (F1,22 = 1.86, p = 0.18). Our results suggest that golden hamsters having body masses being more than four times that of laboratory mice provide a very interesting model to study aspects of lactation and heat production at the same time.
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Affiliation(s)
- Sarah A Ohrnberger
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria.
| | - Katharina Brinkmann
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Rupert Palme
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Teresa G Valencak
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
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37
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Ohrnberger SA, Hambly C, Speakman JR, Valencak TG. Limits to sustained energy intake XXIX: the case of the golden hamster (Mesocricetus auratus). J Exp Biol 2018; 221:jeb.183749. [DOI: 10.1242/jeb.183749] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 09/11/2018] [Indexed: 01/11/2023]
Abstract
Golden hamster females have the shortest known gestation period among placental mammals and at the same time raise very large litters of up to 16 offspring, which are born in a naked and blind state and are able to pick up food from days 12-14 only. We quantified energy metabolism and milk production in female golden hamsters raising offspring under cold (8°C), normal (22°C) and hot (30°C) ambient temperature conditions. We monitored energy intake, subcutaneous body temperature, daily energy expenditure, litter size and pup masses over the course of lactation. Our results show that, in line with the concept of heat dissipation limitation, female golden hamsters had the largest energy intake under the coldest conditions and a significantly lower intake at 30° (partial for influence of ambient temperature: F2,403=5.6; p= 0.004). Metabolisable energy intake as well as milk energy output showed the same pattern and were significantly different between the temperatures (partial for milk energy production: F1,40= 86.4; p<0.0001). With consistently higher subcutaneous temperatures in the reproductive females (F1,813= 36.77; p<0.0001) compared to baseline females. These data suggest that raising offspring in golden hamsters comes at the cost of producing large amounts of body heat up to a level constraining energy intake, similar to that observed in some laboratory mice. Notably, we observed that females seemed to adjust litter size according to their milk production with the smallest litters (3.4±0.7 pups) being raised by hot exposed mothers. Future research is needed to unravel the mechanism by which females assess their own milk production capabilities and how this may be linked to litter size at different ambient temperatures. Golden hamsters reach 8-10 times resting metabolic rate (RMR) when raising offspring under cold conditions, which is compatible with the findings from laboratory mice and other rodents.
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Affiliation(s)
- S. A. Ohrnberger
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
| | - C. Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB 24 2 TZ, UK
| | - J. R. Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB 24 2 TZ, UK
- Institute of Genetics and Developmental Biology, State Key Laboratory of Molecular Developmental Biology, Chinese Academy of Sciences, Beichen Xi Lu, Chaoyang, Beijing, People's Republic of China
| | - T. G. Valencak
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
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38
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Kagya-Agyemang JK, Vaanholt LM, Hambly C, Król E, Mitchell SE, Speakman JR. Limits to sustained energy intake XXVIII: Beneficial effects of high dietary fat on lactation performance in mice. J Exp Biol 2018; 221:jeb.180828. [DOI: 10.1242/jeb.180828] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/20/2018] [Indexed: 12/22/2022]
Abstract
Maximal animal performance may be limited by the ability of animals to dissipate heat; the heat dissipation limitation (HDL) theory. Since diets vary in the incidental heat produced during digestion (specific dynamic action, SDA), the HDL theory predicts lactating female mice consuming diets with lower SDA should have increased reproductive performance. Dietary fat has a lower SDA than dietary carbohydrate. Female mice were fed low (LF), medium (MF) or high fat (HF) diets (10%, 45% and 60% energy from fat respectively) from days 4-18 of lactation. HF and MF-fed mice weaned significantly heavier litters than LF mice. This was because they not only consumed more energy (metabolisable energy intake, Emei; HF:306.5±25.0, MF:340.5±13.5 kJ d−1) at peak lactation, but also delivered more milk energy to their pups (milk energy output, Emilk: 203.2±49.9, 229.3±42.2 kJ d−1 respectively) than the LF-fed mice (Emei =266.7±4.5, Emilk =164.60±30.59 kJ d−1). This effect was greater than predicted from the SDA of the different diets combined with a mathematical model based on the HDL theory. Fatty acid profiles of the diets, milk and pups, showed significant correlations between the profiles. Besides reduced SDA, HF and MF-fed mice were probably able to directly transfer absorbed dietary fat into milk, reducing the heat production of lactogenesis, and enabling them to perform better than expected from the HDL model. In summary, HF and MF diets had beneficial effects on reproductive performance compared to the LF diet because they enabled mice to generate milk more efficiently with less incidental heat production.
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Affiliation(s)
- J. K. Kagya-Agyemang
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
- College of Agriculture Education, University of Education, Winneba, P.O. Box 40, Mampong-Ashanti, Ghana
| | - L. M. Vaanholt
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
| | - C. Hambly
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
| | - E. Król
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
| | - S. E. Mitchell
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
| | - J. R. Speakman
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
- State key laboratory of molecular developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing China
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39
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Sassi PL, Menéndez J, Cuevas MF. Geographic variation in life-history traits: factors shaping energy investment in reproduction in a highland dwelling rodent. J Zool (1987) 2017. [DOI: 10.1111/jzo.12523] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- P. L. Sassi
- CCT-Mendoza CONICET; Grupo de Investigaciones de la Biodiversidad; CONICET; Instituto Argentino de Investigaciones de Zonas Áridas; Mendoza Argentina
- Facultad de Ciencias Exactas y Naturales; Universidad Nacional de Cuyo; Mendoza Argentina
| | - J. Menéndez
- Facultad de Ciencias Exactas y Naturales; Universidad Nacional de Cuyo; Mendoza Argentina
| | - M. F. Cuevas
- CCT-Mendoza CONICET; Grupo de Investigaciones de la Biodiversidad; CONICET; Instituto Argentino de Investigaciones de Zonas Áridas; Mendoza Argentina
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40
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Beale PK, Marsh KJ, Foley WJ, Moore BD. A hot lunch for herbivores: physiological effects of elevated temperatures on mammalian feeding ecology. Biol Rev Camb Philos Soc 2017; 93:674-692. [DOI: 10.1111/brv.12364] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 07/25/2017] [Accepted: 08/09/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Phillipa K. Beale
- Research School of Biology The Australian National University Canberra Australian Capital Territory 2601 Australia
| | - Karen J. Marsh
- Research School of Biology The Australian National University Canberra Australian Capital Territory 2601 Australia
| | - William J. Foley
- Research School of Biology The Australian National University Canberra Australian Capital Territory 2601 Australia
- Animal Ecology and Conservation University of Hamburg, Martin‐Luther‐King‐Platz 3 20146 Hamburg Germany
| | - Ben D. Moore
- Hawkesbury Institute for the Environment Western Sydney University, Locked bag 1797 Penrith New South Wales 2751 Australia
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41
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Orr TJ, Garland T. Complex Reproductive Traits and Whole-Organism Performance. Integr Comp Biol 2017; 57:407-422. [DOI: 10.1093/icb/icx052] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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42
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Li L, Li B, Li M, Niu C, Wang G, Li T, Król E, Jin W, Speakman JR. Brown adipocytes can display a mammary basal myoepithelial cell phenotype in vivo. Mol Metab 2017; 6:1198-1211. [PMID: 29031720 PMCID: PMC5641686 DOI: 10.1016/j.molmet.2017.07.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 07/31/2017] [Indexed: 01/04/2023] Open
Abstract
Objective Previous work has suggested that white adipocytes may also show a mammary luminal secretory cell phenotype during lactation. The capacity of brown and beige/brite adipocytes to display a mammary cell phenotype and the levels at which they demonstrate such phenotypes in vivo is currently unknown. Methods To investigate the putative adipocyte origin of mammary gland cells, we performed genetic lineage-labeling experiments in BAT and the mammary glands. Results These studies indicated that the classic brown adipocytes (Ucp1+) and subcutaneous beige/brite adipocytes (Ucp1−/+) were found in the mammary gland during lactation, when they exhibited a mammary myoepithelial phenotype. Up to 2.5% of the anterior dorsal interscapular mammary myoepithelial cell population had a brown adipocyte origin with an adipose and myoepithelial gene signature during lactation. Eliminating these cells, along with all the brown adipocytes, significantly slowed offspring growth, potentially demonstrating their functional importance. Additionally, we showed mammary epithelial lineage Mmtv+ and Krt14+ cells expressed brown adipocyte markers after weaning, demonstrating that mammary gland cells can display an adipose phenotype. Conclusions The identification of a brown adipocyte origin of mammary myoepithelial cells provides a novel perspective on the interrelationships between adipocytes and mammary cells with implications for our understanding of obesity and breast cancer. Brown adipocytes can show a mammary myoepithelial cell phenotype in vivo. Myf5+/Ucp1+ myoepithelial cells express an adipose and myoepithelial signature. Mammary-derived epithelial cells can display adipose features after weaning.
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Affiliation(s)
- Li Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Baoguo Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Min Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chaoqun Niu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Guanlin Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ting Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Elżbieta Król
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, UK
| | - Wanzhu Jin
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - John R Speakman
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China; Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, UK.
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43
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Stewart F, McAdam A. Wild Peromyscus adjust maternal nest-building behaviour in response to ambient temperature. CAN J ZOOL 2017. [DOI: 10.1139/cjz-2016-0236] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The heat dissipation limit (HDL) hypothesis suggests that energy output during lactation in mammals might be constrained by their ability to dissipate heat. This hypothesis predicts that wild mammals ought to adjust nest insulation in response to heat load, but these predictions have rarely been tested in wild mammals. Here we developed a simple score of nest-building for wild deer mice (Peromyscus maniculatus (Wagner, 1845)) on an ordinal scale from 0 to 4, based on three qualitative and easy to observe aspects of nest-building behaviour: bedding quality, nest shape, and mouse visibility. We used this measure to track 472 nest-building observations across 14 wild P. maniculatus that were brought into captivity and housed under pseudoambient temperatures across one reproductive event. Our observations of nest-building behaviour of the genus Peromyscus Gloger, 1841 provide varying support for the HDL hypothesis; there is a negative effect of ambient temperature on nest-building behaviour and lactating females became more sensitive to temperature as days post partum increased. However, females generally build more elaborate nests in lactation than other reproductive states and there are no effects of litter size, total pup mass, or days post partum on nest scores during lactation. Our observations have broad implications for quantifying behaviours in nest-building species and metabolic relationships in wild mammals.
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Affiliation(s)
- F.E.C. Stewart
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - A.G. McAdam
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
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Wen J, Tan S, Qiao QG, Fan WJ, Huang YX, Cao J, Liu JS, Wang ZX, Zhao ZJ. Sustained energy intake in lactating Swiss mice: a dual modulation process. J Exp Biol 2017; 220:2277-2286. [DOI: 10.1242/jeb.157107] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 04/04/2017] [Indexed: 12/15/2022]
Abstract
Limits to sustained energy intake (SusEI) during lactation are important because they provide an upper boundary below which females must trade-off competing physiological activities. To date, SusEI is thought to be limited either by the capacity of the mammary glands to produce milk (the peripheral limitation hypothesis), or by a female's ability to dissipate body heat (the heat dissipation hypothesis). In the present study, we examined the effects of litter size and ambient temperature on a set of physiological, behavioral, and morphological indicators of SusEI and reproductive performance in lactating Swiss mice. Our results indicate that energy input, output, and mammary gland mass increased with litter size, whereas pup body mass and survival rate decreased. The body temperature increased significantly, while food intake (18g/d at 21°C vs 10g/d at 30°C), thermal conductance (lower by 20-27% at 30°C than 21°C), litter mass and MEO decreased significantly in the females raising large litter size at 30°C compared to those at 21°C. Furthermore, an interaction between ambient temperature and litter size affected females' energy budget, imposing strong constraints on SusEI. Together, out data suggest that the limitation may be caused by both mammary glands and heat dissipation, i.e. the limits to mammary gland is dominant at the room temperature, but heat limitation is more significant at warm temperatures. Further, the level of heat dissipation limits may be temperature dependent, shifting down with increasing temperature.
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Affiliation(s)
- Jing Wen
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Song Tan
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Qing-Gang Qiao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Wei-Jia Fan
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Yi-Xin Huang
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Jing Cao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Jin-Song Liu
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Zuo-Xin Wang
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA
| | - Zhi-Jun Zhao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
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45
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Zhu WL, Zhang H, Cheng JL, Cai JH, Meng LH. Limits to Sustainable Energy Intake during Lactation inEothenomys miletus: Effects of Fur-Shaving and Litter Size. MAMMAL STUDY 2016. [DOI: 10.3106/041.041.0406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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46
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Ohrnberger SA, Monclús R, Rödel HG, Valencak TG. Ambient temperature affects postnatal litter size reduction in golden hamsters. Front Zool 2016; 13:51. [PMID: 27904644 PMCID: PMC5121935 DOI: 10.1186/s12983-016-0183-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 11/15/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To better understand how different ambient temperatures during lactation affect survival of young, we studied patterns of losses of pups in golden hamsters (Mesocricetus auratus) at different ambient temperatures in the laboratory, mimicking temperature conditions in natural habitats. Golden hamsters produce large litters of more than 10 young but are also known to wean fewer pups at the end of lactation than they give birth to. We wanted to know whether temperature affects litter size reductions and whether the underlying causes of pup loss were related to maternal food (gross energy) intake and reproductive performance, such as litter growth. For that, we exposed lactating females to three different ambient temperatures and investigated associations with losses of offspring between birth and weaning. RESULTS Overall, around one third of pups per litter disappeared, obviously consumed by the mother. Such litter size reductions were greatest at 30 °C, in particular during the intermediate postnatal period around peak lactation. Furthermore, litter size reductions were generally higher in larger litters. Maternal gross energy intake was highest at 5 °C suggesting that mothers were not limited by milk production and might have been able to raise a higher number of pups until weaning. This was further supported by the fact that the daily increases in litter mass as well as in the individual pup body masses, a proxy of mother's lactational performance, were lower at higher ambient temperatures. CONCLUSIONS We suggest that ambient temperatures around the thermoneutral zone and beyond are preventing golden hamster females from producing milk at sufficient rates. Around two thirds of the pups per litter disappeared at high temperature conditions, and their early growth rates were significantly lower than at lower ambient temperatures. It is possible that these losses are due to an intrinsic physiological limitation (imposed by heat dissipation) compromising maternal energy intake and milk production.
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Affiliation(s)
- Sarah A. Ohrnberger
- Institute of Physiology, Pathophysiology and Biophysics, Veterinary University Vienna, Vienna, Austria
| | - Raquel Monclús
- Ecologie Systématique Evolution, University Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, F-91400 Orsay, France
| | - Heiko G. Rödel
- Laboratoire d’Ethologie Expérimentale et Comparée E.A. 4443, Université Paris 13, Sorbonne Paris Cité, F-93430 Villetaneuse, France
| | - Teresa G. Valencak
- Institute of Physiology, Pathophysiology and Biophysics, Veterinary University Vienna, Vienna, Austria
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47
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Zhao ZJ, Li L, Yang DB, Chi QS, Hambly C, Speakman JR. Limits to sustained energy intake XXV: milk energy output and thermogenesis in Swiss mice lactating at thermoneutrality. Sci Rep 2016; 6:31626. [PMID: 27554919 PMCID: PMC4995430 DOI: 10.1038/srep31626] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/22/2016] [Indexed: 01/13/2023] Open
Abstract
Previous studies at 21 °C and 5 °C suggest that in Swiss mice sustained energy intake (SusEI) and reproductive performance are constrained by the mammary capacity to produce milk. We aimed to establish if this constraint also applied at higher ambient temperature (30 °C). Female Swiss mice lactating at 30 °C had lower asymptotic food intake and weaned lighter litters than those at 21 °C. Resting metabolic rate, daily energy expenditure, milk energy output and suckling time were all lower at 30 °C. In a second experiment we gave mice at 30 °C either 6 or 9 pups to raise. Female performance was independent of litter size, indicating that it is probably not controlled by pup demands. In a third experiment we exposed only the mother, or only the offspring to the elevated temperature. In this case the performance of the mother was only reduced when she was exposed, and not when her pups were exposed, showing that the high temperature directly constrains female performance. These data suggest that at 30 °C SusEI and reproductive performance are likely constrained by the capacity of females to dissipate body heat, and not indirectly via pup demands. Constraints seem to change with ambient temperature in this strain of mouse.
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Affiliation(s)
- Zhi-Jun Zhao
- School of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang 325027, China
| | - Li Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100100, China
| | - Deng-Bao Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100100, China
- State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China
| | - Qing-Sheng Chi
- State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China
| | - Catherine Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, UK
| | - John R. Speakman
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100100, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, UK
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48
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Fischer AW, Csikasz RI, von Essen G, Cannon B, Nedergaard J. No insulating effect of obesity. Am J Physiol Endocrinol Metab 2016; 311:E202-13. [PMID: 27189935 DOI: 10.1152/ajpendo.00093.2016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 05/11/2016] [Indexed: 01/08/2023]
Abstract
The development of obesity may be aggravated if obesity itself insulates against heat loss and thus diminishes the amount of food burnt for body temperature control. This would be particularly important under normal laboratory conditions where mice experience a chronic cold stress (at ≈20°C). We used Scholander plots (energy expenditure plotted against ambient temperature) to examine the insulation (thermal conductance) of mice, defined as the inverse of the slope of the Scholander curve at subthermoneutral temperatures. We verified the method by demonstrating that shaved mice possessed only half the insulation of nonshaved mice. We examined a series of obesity models [mice fed high-fat diets and kept at different temperatures, classical diet-induced obese mice, ob/ob mice, and obesity-prone (C57BL/6) vs. obesity-resistant (129S) mice]. We found that neither acclimation temperature nor any kind or degree of obesity affected the thermal insulation of the mice when analyzed at the whole mouse level or as energy expenditure per lean weight. Calculation per body weight erroneously implied increased insulation in obese mice. We conclude that, in contrast to what would be expected, obesity of any kind does not increase thermal insulation in mice, and therefore, it does not in itself aggravate the development of obesity. It may be discussed as to what degree of effect excess adipose tissue has on insulation in humans and especially whether significant metabolic effects are associated with insulation in humans.
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Affiliation(s)
- Alexander W Fischer
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden; and Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Robert I Csikasz
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden; and
| | - Gabriella von Essen
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden; and
| | - Barbara Cannon
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden; and
| | - Jan Nedergaard
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden; and
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49
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Książek A, Konarzewski M. Heat dissipation does not suppress an immune response in laboratory mice divergently selected for basal metabolic rate (BMR). ACTA ACUST UNITED AC 2016; 219:1542-51. [PMID: 26944492 DOI: 10.1242/jeb.129312] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 03/01/2016] [Indexed: 01/01/2023]
Abstract
The capacity for heat dissipation is considered to be one of the most important constraints on rates of energy expenditure in mammals. To date, the significance of this constraint has been tested exclusively under peak metabolic demands, such as during lactation. Here, we used a different set of metabolic stressors, which do not induce maximum energy expenditures and yet are likely to expose the potential constraining effect of heat dissipation. We compared the physiological responses of mice divergently selected for high (H-BMR) and low basal metabolic rate (L-BMR) to simultaneous exposure to the keyhole limpet haemocyanin (KLH) antigen and high ambient temperature (Ta). At 34°C (and at 23°C, used as a control), KLH challenge resulted in a transient increase in core body temperature (Tb) in mice of both line types (by approximately 0.4°C). Warm exposure did not produce line-type-dependent differences in Tb (which was consistently higher by ca. 0.6°C in H-BMR mice across both Ta values), nor did it result in the suppression of antibody synthesis. These findings were also supported by the lack of between-line-type differences in the mass of the thymus, spleen or lymph nodes. Warm exposure induced the downsizing of heat-generating internal organs (small intestine, liver and kidneys) and an increase in intrascapular brown adipose tissue mass. However, these changes were similar in scope in both line types. Mounting a humoral immune response in selected mice was therefore not affected by ambient temperature. Thus, a combined metabolic challenge of high Ta and an immune response did not appreciably compromise the capacity to dissipate heat, even in the H-BMR mice.
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Affiliation(s)
- Aneta Książek
- Institute of Biology, University of Białystok, Ciołkowskiego 1J, Białystok 15-245, Poland
| | - Marek Konarzewski
- Institute of Biology, University of Białystok, Ciołkowskiego 1J, Białystok 15-245, Poland
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50
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Gamo Y, Bernard A, Troup C, Munro F, Derrer K, Jeannesson N, Campbell A, Gray H, Miller J, Dixon J, Mitchell SE, Hambly C, Vaanholt LM, Speakman JR. Limits to sustained energy intake XXIV: impact of suckling behaviour on the body temperatures of lactating female mice. Sci Rep 2016; 6:25665. [PMID: 27157478 PMCID: PMC4860708 DOI: 10.1038/srep25665] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 04/06/2016] [Indexed: 11/29/2022] Open
Abstract
The objective of this study was to investigate the potential causes of high body temperature (Tb) during lactation in mice as a putative limit on energy intake. In particular we explored whether or not offspring contributed to heat retention in mothers while suckling. Tb and physical activity were monitored in 26 female MF1 mice using intraperitoneally implanted transmitters. In addition, maternal behaviour was scored each minute for 8 h d(-1) throughout lactation. Mothers that raised larger litters tended to have higher Tb while nursing inside nests (P < 0.05), suggesting that nursing offspring may have influenced heat retention. However, Tb during nursing was not higher than that recorded during other behaviours. In addition, the highest Tb during the observation period was not measured during nursing behaviour. Finally, there was no indication that mothers discontinued suckling because of a progressive rise in their Tb while suckling. Tb throughout lactation was correlated with daily increases in energy intake. Chronic hyperthermia during lactation was not caused by increased heat retention due to surrounding offspring. Other factors, like metabolic heat produced as a by-product of milk production or energy intake may be more important factors. Heat dissipation limits are probably not a phenomenon restricted to lactation.
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Affiliation(s)
- Y. Gamo
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - A. Bernard
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - C. Troup
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - F. Munro
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - K. Derrer
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - N. Jeannesson
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - A. Campbell
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - H. Gray
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - J. Miller
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - J. Dixon
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - S. E. Mitchell
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - C. Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - L. M. Vaanholt
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
| | - J. R. Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, Scotland, UK
- Institute of Genetics and Developmental Biology, State Key Laboratory of Molecular Developmental Biology, Chinese Academy of Sciences, Beichen Xi Lu, Chaoyang, Beijing, People’s Republic of China
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