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Mikkelsen AJ, Hobson KA, Sergiel A, Hertel AG, Selva N, Zedrosser A. Testing foraging optimization models in brown bears: Time for a paradigm shift in nutritional ecology? Ecology 2024; 105:e4228. [PMID: 38071743 DOI: 10.1002/ecy.4228] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 10/30/2023] [Indexed: 12/31/2023]
Abstract
How organisms obtain energy to survive and reproduce is fundamental to ecology, yet researchers use theoretical concepts represented by simplified models to estimate diet and predict community interactions. Such simplistic models can sometimes limit our understanding of ecological principles. We used a polyphagous species with a wide distribution, the brown bear (Ursus arctos), to illustrate how disparate theoretical frameworks in ecology can affect conclusions regarding ecological communities. We used stable isotope measurements (δ13 C, δ15 N) from hairs of individually monitored bears in Sweden and Bayesian mixing models to estimate dietary proportions of ants, moose, and three berry species to compare with other brown bear populations. We also developed three hypotheses based on predominant foraging literature, and then compared predicted diets to field estimates. Our three models assumed (1) bears forage to optimize caloric efficiency (optimum foraging model), predicting bears predominately eat berries (~70% of diet) and opportunistically feed on moose (Alces alces) and ants (Formica spp. and Camponotus spp; ~15% each); (2) bears maximize meat intake (maximizing fitness model), predicting a diet of 35%-50% moose, followed by ants (~30%), and berries (~15%); (3) bears forage to optimize macronutrient balance (macronutrient model), predicting a diet of ~22% (dry weight) or 17% metabolizable energy from proteins, with the rest made up of carbohydrates and lipids (~49% and 29% dry matter or 53% and 30% metabolizable energy, respectively). Bears primarily consumed bilberries (Vaccinium myrtillus; 50%-55%), followed by lingonberries (V. vitis-idaea; 22%-30%), crowberries (Empetrum nigrum; 8%-15%), ants (5%-8%), and moose (3%-4%). Dry matter dietary protein was lower than predicted by the maximizing fitness model and the macronutrient balancing model, but protein made up a larger proportion of the metabolizable energy than predicted. While diets most closely resembled predictions from optimal foraging theory, none of the foraging hypotheses fully described the relationship between foraging and ecological niches in brown bears. Acknowledging and broadening models based on foraging theories is more likely to foster novel discoveries and insights into the role of polyphagous species in ecosystems and we encourage this approach.
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Affiliation(s)
- Ashlee J Mikkelsen
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Bø, Norway
| | - Keith A Hobson
- Environment and Climate Change Canada, Saskatoon, Saskatchewan, Canada
- Department of Biology, University of Western Ontario, London, Ontario, Canada
| | - Agnieszka Sergiel
- Institute of Nature Conservation, Polish Academy of Sciences, Krakow, Poland
| | - Anne G Hertel
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Bø, Norway
- Department of Biology, Ludwig Maximilians University of Munich, Planegg, Germany
| | - Nuria Selva
- Institute of Nature Conservation, Polish Academy of Sciences, Krakow, Poland
| | - Andreas Zedrosser
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Bø, Norway
- Department of Integrative Biology, University of Natural Recourses and Applied Life Sciences, Vienna, Austria
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2
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Doss EM, Jouffroy M, Rey B, Cohas A, von Hardenberg A, Smith TE. Technical validation and a comparison of two methods to quantify individual levels of glucocorticoids in Alpine marmot hair. MethodsX 2023; 11:102418. [PMID: 37846357 PMCID: PMC10577059 DOI: 10.1016/j.mex.2023.102418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/04/2023] [Indexed: 10/18/2023] Open
Abstract
Quantification of cortisol concentration in hair has become a promising conservation tool for non-invasive monitoring of "stress" in wild populations, yet this method needs to be carefully validated for each species. The goals of the study were:•Immunologically validate two methods (study 1 and 2 respectively) to extract and quantify cortisol in the hair of wild Alpine marmots.•Compare the amount of cortisol extracted from hair samples using two methods i.e. cut into fine pieces (study 1) and hair samples pulverized using a ball mill (study 2).•Determine the extent to which methods in study 2 could provide individual specific hair cortisol (HC) measures when samples were taken from the same body location. Within and between individual variations in HC levels were examined from multiple hair samples from 14 subjects in study 2. We evaluated if inter-individual variations in HC levels could be explained by sex and age.At least twice the amount of cortisol was obtained per g/hair when samples were pulverized in a ball mill prior to extraction compared to when cut into pieces. Our methods demonstrated intra-individual consistency in HC at a given time point: inter-individual variation in HC was three times larger than within individual variance. Sex and age did not impact HC levels.
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Affiliation(s)
- Elina Marielle Doss
- University of Chester, Conservation Biology Research Group, Chester, United Kingdom
| | - Mathilde Jouffroy
- University of Chester, Conservation Biology Research Group, Chester, United Kingdom
| | - Benjamin Rey
- Université de Lyon, Laboratoire de Biométrie et Biologie Évolutive, Université Lyon1, UMR-CNRS 5558, Villeurbanne, France
| | - Aurélie Cohas
- Université de Lyon, Laboratoire de Biométrie et Biologie Évolutive, Université Lyon1, UMR-CNRS 5558, Villeurbanne, France
| | - Achaz von Hardenberg
- University of Chester, Conservation Biology Research Group, Chester, United Kingdom
| | - Tessa Ellen Smith
- University of Chester, Conservation Biology Research Group, Chester, United Kingdom
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3
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Lazarus M, Sergiel A, Ferenčaković M, Orct T, Kapronczai L, Pađen L, Janz DM, Reljić S, Zwijacz-Kozica T, Zięba F, Selva N, Huber Đ. Stress and reproductive hormones in hair associated with contaminant metal(loid)s of European brown bear (Ursus arctos). CHEMOSPHERE 2023; 325:138354. [PMID: 36907481 DOI: 10.1016/j.chemosphere.2023.138354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 06/18/2023]
Abstract
Environmental contaminants like arsenic (As), cadmium (Cd), mercury (Hg) or lead (Pb) may disrupt hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes due to their endocrine toxicity potential. Resulting long-term physiological stress or adverse effects on wildlife reproduction and ontogeny may cause detrimental effects at the individual and population levels. However, data on environmental metal(loid)s' impact on reproductive and stress hormones in wildlife, especially large terrestrial carnivores, are scarce. Hair cortisol, progesterone and testosterone concentrations were quantified and modelled with hair As, Cd, total Hg, Pb, biological, environmental and sampling factors to test for potential effects in free-ranging brown bears (Ursus arctos) from Croatia (N = 46) and Poland (N = 27). Testosterone in males (N = 48) and females (N = 25) showed positive associations with Hg and an interaction between Cd and Pb, but a negative association with interaction between age and Pb. Higher testosterone was found in hair during its growth phase compared to quiescent phase. Body condition index was negatively associated with hair cortisol and positively associated with hair progesterone. Year and conditions of sampling were important for cortisol variation, while maturity stage for progesterone variation (lower concentrations in cubs and yearlings compared to subadult and adult bears). These findings suggest that environmental levels of Cd, Hg and Pb might influence the HPG axis in brown bears. Hair was shown to be a reliable non-invasive sample for investigating hormonal fluctuations in wildlife while addressing individual and sampling specificities.
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Affiliation(s)
- Maja Lazarus
- Institute for Medical Research and Occupational Health, Zagreb, Croatia.
| | - Agnieszka Sergiel
- Institute of Nature Conservation of Polish Academy of Sciences, Kraków, Poland.
| | | | - Tatjana Orct
- Institute for Medical Research and Occupational Health, Zagreb, Croatia.
| | | | - Lana Pađen
- Faculty of Veterinary Medicine, University of Zagreb, Croatia.
| | - David M Janz
- Toxicology Centre, University of Saskatchewan, Saskatoon, Canada; Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Canada.
| | - Slaven Reljić
- Faculty of Veterinary Medicine, University of Zagreb, Croatia.
| | | | | | - Nuria Selva
- Institute of Nature Conservation of Polish Academy of Sciences, Kraków, Poland; Departamento de Ciencias Integradas, Facultad de Ciencias Experimentales, Centro de Estudios Avanzados en Física, Matemáticas y Computación, Universidad de Huelva, Huelva, Spain.
| | - Đuro Huber
- Institute of Nature Conservation of Polish Academy of Sciences, Kraków, Poland; Faculty of Veterinary Medicine, University of Zagreb, Croatia.
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4
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Rakic F, Fernandez-Aguilar X, Pruvot M, Whiteside DP, Mastromonaco GF, Leclerc LM, Jutha N, Kutz SJ. Variation of hair cortisol in two herds of migratory caribou ( Rangifer tarandus): implications for health monitoring. CONSERVATION PHYSIOLOGY 2023; 11:coad030. [PMID: 37228297 PMCID: PMC10203588 DOI: 10.1093/conphys/coad030] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 04/03/2023] [Accepted: 05/17/2023] [Indexed: 05/27/2023]
Abstract
Migratory caribou (Rangifer tarandus sspp.) is an ecotype of conservation concern that is experiencing increased cumulative stressors associated with rapid climate change and development in Arctic Canada. Increasingly, hair cortisol concentrations (HCCs) are being used to monitor seasonal hypothalamic-pituitary-adrenal axis activity of ungulate populations; yet, the effect of key covariates for caribou (sex, season, sampling source, body location) are largely unknown. The objectives of this research were 4-fold: first, we assessed the impact of body location (neck, rump) sampling sites on HCC; second, we assessed key covariates (sex, sampling method, season) impacting HCCs of caribou; third, we investigated inter-population (Dolphin and Union (DU), Bluenose-East (BNE)) and inter-annual differences in HCC and fourth, we examined the association between HCCs and indices of biting insect activity on the summer range (oestrid index, mosquito index). We examined hair from 407 DU and BNE caribou sampled by harvesters or during capture-collaring operations from 2012 to 2020. Linear mixed-effect models were used to assess the effect of body location on HCC and generalized least squares regression (GLS) models were used to examine the impacts of key covariates, year and herd and indices of biting insect harassment. HCC varied significantly by body location, year, herd and source of samples (harvester vs capture). HCC was higher in samples taken from the neck and in the DU herd compared with the BNE, decreased linearly over time and was higher in captured versus hunted animals (P < 0.05). There was no difference in HCC between sexes, and indices of biting insect harassment in the previous year were not significantly associated with HCC. This study identifies essential covariates impacting the HCC of caribou that must be accounted for in sampling, monitoring and data interpretation.
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Affiliation(s)
- F Rakic
- Corresponding author: Department of Ecosystem and Public Health – Faculty of Veterinary Medicine, University of Calgary; 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada.
| | - X Fernandez-Aguilar
- Department of Ecosystem and Public Health – Faculty of Veterinary Medicine, University of Calgary; 3280 Hospital Drive NW, Calgary, Alberta, Canada, T2N 4Z6
| | - M Pruvot
- Department of Ecosystem and Public Health – Faculty of Veterinary Medicine, University of Calgary; 3280 Hospital Drive NW, Calgary, Alberta, Canada, T2N 4Z6
| | - D P Whiteside
- Department of Ecosystem and Public Health – Faculty of Veterinary Medicine, University of Calgary; 3280 Hospital Drive NW, Calgary, Alberta, Canada, T2N 4Z6
| | - G F Mastromonaco
- Reproductive Sciences Unit, Toronto Zoo, 361A Old Finch Avenue, Scarborough, Ontario, Canada, M1B 5K7
| | - L M Leclerc
- Department of Environment, Government of Nunavut, P.O. Box 377, Kugluktuk, Nunavut, Canada, X0B 0E0
| | - N Jutha
- Department of Environment and Natural Resources, Government of the Northwest Territories, 5112 52 st, Yellowknife, The Northwest Territories, Canada, X1A 2L9
| | - S J Kutz
- Department of Ecosystem and Public Health – Faculty of Veterinary Medicine, University of Calgary; 3280 Hospital Drive NW, Calgary, Alberta, Canada, T2N 4Z6
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5
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Babic NL, Johnstone CP, Reljić S, Sergiel A, Huber Đ, Reina RD. Evaluation of physiological stress in free-ranging bears: current knowledge and future directions. Biol Rev Camb Philos Soc 2023; 98:168-190. [PMID: 36176191 PMCID: PMC10086944 DOI: 10.1111/brv.12902] [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: 10/29/2021] [Revised: 08/25/2022] [Accepted: 08/31/2022] [Indexed: 01/12/2023]
Abstract
Stress responses, which are mediated by the neurogenic system (NS) and hypothalamic-pituitary-adrenal (HPA) axis help vertebrates maintain physiological homeostasis. Fight-or-flight responses are activated by the NS, which releases norepinephrine/noradrenaline and epinephrine/adrenaline in response to immediate stressors, whilst the HPA axis releases glucocorticoid hormones (e.g. cortisol and corticosterone) to help mitigate allostatic load. There have been many studies on stress responses of captive animals, but they are not truly reflective of typical ranges or the types of stressors encountered by free-ranging wildlife, such as responses and adaptation to environmental change, which are particularly important from a conservation perspective. As stress can influence the composition of age and sex classes of free-ranging populations both directly and indirectly, ecological research must be prioritised towards more vulnerable taxa. Generally, large predators tend to be particularly at risk of anthropogenically driven population declines because they exhibit reduced behavioural plasticity required to adapt to changing landscapes and exist in reduced geographic ranges, have small population sizes, low fecundity rates, large spatial requirements and occupy high trophic positions. As a keystone species with a long history of coexistence with humans in highly anthropogenic landscapes, there has been growing concern about how humans influence bear behaviour and physiology, via numerous short- and long-term stressors. In this review, we synthesise research on the stress response in free-ranging bear populations and evaluate the effectiveness and limitations of current methodology in measuring stress in bears to identify the most effective metrics for future research. Particularly, we integrate research that utilised haematological variables, cardiac monitors and Global Positioning System (GPS) collars, serum/plasma and faecal glucocorticoid concentrations, hair cortisol levels, and morphological metrics (primarily skulls) to investigate the stress response in ursids in both short- and long-term contexts. We found that in free-ranging bears, food availability and consumption have the greatest influence on individual stress, with mixed responses to anthropogenic influences. Effects of sex and age on stress are also mixed, likely attributable to inconsistent methods. We recommend that methodology across all stress indicators used in free-ranging bears should be standardised to improve interpretation of results and that a wider range of species should be incorporated in future studies.
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Affiliation(s)
- Natarsha L Babic
- School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, 3800, Victoria, Australia
| | - Christopher P Johnstone
- School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, 3800, Victoria, Australia
| | - Slaven Reljić
- Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, Zagreb, 10000, Croatia
| | - Agnieszka Sergiel
- Institute of Nature Conservation, Polish Academy of Sciences, Adama Mickiewicza 33, Krakow, 31120, Poland
| | - Đuro Huber
- Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, Zagreb, 10000, Croatia.,Institute of Nature Conservation, Polish Academy of Sciences, Adama Mickiewicza 33, Krakow, 31120, Poland
| | - Richard D Reina
- School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, 3800, Victoria, Australia
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6
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Fokidis HB, Brock T, Newman C, Macdonald DW, Buesching CD. Assessing chronic stress in wild mammals using claw-derived cortisol: a validation using European badgers ( Meles meles). CONSERVATION PHYSIOLOGY 2023; 11:coad024. [PMID: 37179707 PMCID: PMC10171820 DOI: 10.1093/conphys/coad024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 01/26/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023]
Abstract
Measuring stress experienced by wild mammals is increasingly important in the context of human-induced rapid environmental change and initiatives to mitigate human-wildlife conflicts. Glucocorticoids (GC), such as cortisol, mediate responses by promoting physiological adjustments during environmental perturbations. Measuring cortisol is a popular technique; however, this often reveals only recent short-term stress such as that incurred by restraining the animal to sample blood, corrupting the veracity of this approach. Here we present a protocol using claw cortisol, compared with hair cortisol, as a long-term stress bio-indicator, which circumvents this constraint, where claw tissue archives the individual's GC concentration over preceding weeks. We then correlate our findings against detailed knowledge of European badger life history stressors. Based on a solid-phase extraction method, we assessed how claw cortisol concentrations related to season and badger sex, age and body-condition using a combination of generalized linear mixed models (GLMM) (n = 668 samples from 273 unique individuals) followed by finer scale mixed models for repeated measures (MMRM) (n = 152 re-captured individuals). Claw and hair cortisol assays achieved high accuracy, precision and repeatability, with similar sensitivity. The top GLMM model for claw cortisol included age, sex, season and the sex*season interaction. Overall, claw cortisol levels were significantly higher among males than females, but strongly influenced by season, where females had higher levels than males in autumn. The top fine scale MMRM model included sex, age and body condition, with claw cortisol significantly higher in males, older and thinner individuals. Hair cortisol was more variable than claw; nevertheless, there was a positive correlation after removing 34 outliers. We discuss strong support for these stress-related claw cortisol patterns from previous studies of badger biology. Given the potential of this technique, we conclude that it has broad application in conservation biology.
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Affiliation(s)
- H Bobby Fokidis
- Corresponding author: Department of Biology, Rollins College, Winter Park, Florida, USA.
| | - Taylor Brock
- Department of Biology, Rollins College, 1000 Holt Avenue, Winter Park, Florida, 32789-4499, USA
| | - Chris Newman
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abindgon Rd, Tubney, OX13 5QL, UK
| | - David W Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abindgon Rd, Tubney, OX13 5QL, UK
| | - Christina D Buesching
- Irving K. Barber Faculty of Science, University of British Columbia, Okanagan campus, 3187 University Way, Kelowna, British Columbia, V1V1V7, Canada
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7
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Wilson AE, Sergiel A, Selva N, Swenson JE, Zedrosser A, Stenhouse G, Janz DM. Correcting for enzyme immunoassay changes in long term monitoring studies. MethodsX 2021; 8:101212. [PMID: 34434735 PMCID: PMC8374155 DOI: 10.1016/j.mex.2021.101212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 01/02/2021] [Indexed: 11/18/2022] Open
Abstract
Enzyme immunoassays (EIAs) are a common tool for measuring steroid hormones in wildlife due to their low cost, commercial availability, and rapid results. Testing technologies improve continuously, sometimes requiring changes in protocols or crucial assay components. Antibody replacement between EIA kits can cause differences in EIA sensitivity, which can hinder monitoring hormone concentration over time. The antibody in a common cortisol EIA kit used for long-term monitoring of stress in wildlife was replaced in 2014, causing differences in cross reactivity and standard curve concentrations. Therefore, the objective of this study was to develop a method to standardize results following changes in EIA sensitivity. We validated this method using cortisol concentrations measured in the hair of brown bears (Ursus arctos).We used a simple linear regression to model the relationship between cortisol concentrations using kit 1 and kit 2. We found a linear relationship between the two kits (R2 = 0.85) and used the regression equation (kit2 = (0.98 × kit1) + 1.65) to predict cortisol concentrations in re-measured samples. Mean predicted percent error was 16% and 72% of samples had a predicted percent error <20%, suggesting that this method is well-suited for correcting changes in EIA sensitivity.
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Affiliation(s)
- Abbey E. Wilson
- Department of Veterinary Biomedical Sciences, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3, Canada
- Corresponding author.
| | - Agnieszka Sergiel
- Institute of Nature Conservation, Polish Academy of Sciences, Adama Mickiewicza 33, 31120 Krakow, Poland
| | - Nuria Selva
- Institute of Nature Conservation, Polish Academy of Sciences, Adama Mickiewicza 33, 31120 Krakow, Poland
| | - Jon E. Swenson
- Faculty of Environmental Science and Natural Resource Management, Norwegian University of Life Sciences, Høgskoleveien 12, NO-1432, Norway
| | - Andreas Zedrosser
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Gullbringvegen 36, 3800 Bø, Norway
- Institute for Wildlife Biology and Game Management, University for Natural Resources and Life Sciences, Gregor-Mendel-Straße 33, 1180 Vienna, Austria
| | - Gordon Stenhouse
- fRI Research, Grizzly Bear Program, 1176 Switzer Drive, Hinton T7V 1V3, AB, Canada
| | - David M. Janz
- Department of Veterinary Biomedical Sciences, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3, Canada
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8
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Filacorda S, Comin A, Franchini M, Frangini L, Pesaro S, Pezzin EN, Prandi A. Cortisol in Hair: Do Habitat Fragmentation and Competition with Golden Jackal (Canis aureus) Measurably Affect the Long-Term Physiological Response in European Wildcat (Felis silvestris)? ANN ZOOL FENN 2021. [DOI: 10.5735/086.059.0101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Stefano Filacorda
- Department of Agri-Food, Environmental and Animal Sciences, University of Udine, Via Sondrio 2/A, IT-33100 Udine, Italy
| | - Antonella Comin
- Department of Agri-Food, Environmental and Animal Sciences, University of Udine, Via Sondrio 2/A, IT-33100 Udine, Italy
| | - Marcello Franchini
- Department of Agri-Food, Environmental and Animal Sciences, University of Udine, Via Sondrio 2/A, IT-33100 Udine, Italy
| | - Lorenzo Frangini
- Department of Agri-Food, Environmental and Animal Sciences, University of Udine, Via Sondrio 2/A, IT-33100 Udine, Italy
| | - Stefano Pesaro
- Department of Agri-Food, Environmental and Animal Sciences, University of Udine, Via Sondrio 2/A, IT-33100 Udine, Italy
| | - Eva Nilanthi Pezzin
- Department of Biology, University of Padova, Via Ugo Bassi 58/B, IT-35131 Padova, Italy
| | - Alberto Prandi
- Department of Agri-Food, Environmental and Animal Sciences, University of Udine, Via Sondrio 2/A, IT-33100 Udine, Italy
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Di Francesco J, Mastromonaco GF, Checkley SL, Blake J, Rowell JE, Kutz S. Qiviut cortisol reflects hypothalamic-pituitary-adrenal axis activity in muskoxen (Ovibos moschatus). Gen Comp Endocrinol 2021; 306:113737. [PMID: 33610573 DOI: 10.1016/j.ygcen.2021.113737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/25/2021] [Accepted: 02/09/2021] [Indexed: 01/10/2023]
Abstract
Muskoxen (Ovibos moschatus) are increasingly exposed to a broad diversity of stressors in their rapidly changing Arctic environment. There is an urgent need to develop validated tools to monitor the impact of these stressors on the hypothalamic-pituitary-adrenal (HPA) axis activity of muskoxen to help inform conservation actions. Here, we evaluated whether muskox qiviut (dense wooly undercoat) cortisol accurately reflects changes in HPA axis activity. Two repeated pharmacological challenges, involving weekly administrations of saline (control group) or adrenocorticotropic hormone (ACTH) during five consecutive weeks, were done on captive muskoxen, in winter (no hair growth) and summer (maximum hair growth). Pre-challenge qiviut cortisol levels were significantly higher in the shoulder than in the neck, but neither differed from rump concentrations. Qiviut cortisol levels significantly increased (p < 0.001) in response to the administration of ACTH during the hair growth phase, but not in the absence of growth (p = 0.84). Cortisol levels in the qiviut segment grown during the summer challenge increased significantly over a six-month period in the ACTH-injected muskoxen with a similar trend occurring in the control animals. Finally, cortisol levels in shed qiviut were significantly higher and not correlated to those of fully grown qiviut shaved three months earlier. Our results show that cortisol is deposited in qiviut during its growth and that qiviut cortisol can thus be used as an integrated measure of HPA axis activity over the period of the hair's growth. Differences in qiviut cortisol across body regions, significant differences in qiviut segments over time, and differences between shed qiviut versus unshed qiviut, highlight the importance of consistent design and methodology for sample collection and analyses in order to account for sources of variation when using qiviut cortisol as a biomarker of HPA axis activity in muskoxen.
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Affiliation(s)
- J Di Francesco
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada; French Armed Forces Center for Epidemiology and Public Health (CESPA), Marseille, France.
| | - G F Mastromonaco
- Reproductive Sciences Unit, Toronto Zoo, 361A Old Finch Avenue, Scarborough, Ontario M1B 5K7, Canada
| | - S L Checkley
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada
| | - J Blake
- Animal Resources Center, University of Alaska Fairbanks, 1033 Sheenjek Drive, Fairbanks, AK 99775-6980, USA
| | - J E Rowell
- Agricultural and Forestry Experiment Station, University of Alaska Fairbanks, Fairbanks, AK 99775-7500, USA
| | - S Kutz
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada
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10
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Cattet M, Janz DM, Kapronczai L, Erlenbach JA, Jansen HT, Nelson OL, Robbins CT, Stenhouse GB. Cortisol levels in blood and hair of unanesthetized grizzly bears (Ursus arctos) following intravenous cosyntropin injection. Vet Med Sci 2021; 7:2032-2038. [PMID: 33978314 PMCID: PMC8464257 DOI: 10.1002/vms3.523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 02/23/2021] [Accepted: 04/22/2021] [Indexed: 11/25/2022] Open
Abstract
Hair cortisol concentration (HCC) is being used increasingly to evaluate long‐term stress in many mammalian species. Most of the cortisol is assumed to passively diffuse from circulating blood into hair follicles and gradually accumulate in growing hair. However, our research with free‐ranging grizzly bears (Ursus arctos) suggests HCC increases significantly within several hours following capture, a time too brief to be explained by this mechanism alone. In this study with captive grizzly bears, we sought to determine if a brief spike in blood cortisol concentration, thus mimicking a single stressful event, would cause an increase in HCC over a 7‐day period. To do this, we administered a single intravenous dose (5 μg/kg) of cosyntropin to three captive unanaesthetised adult female grizzly bears on two occasions, during April when hair growth was arrested and during August when hair was growing. In both trials, the cosyntropin caused a two‐fold or greater increase in serum cortisol levels within 1 hr but did not appear to influence HCC at 1, 48, and 168 hr following cosyntropin administration. We conclude the cosyntropin‐induced cortisol spike was likely insignificant when compared to the adrenocortical response that occurs in free‐ranging bears when captured. We suggest further study with a larger sample of captive bears to evaluate the combined effects of anaesthesia and multiple doses of cosyntropin administered over several hours would better simulate the adrenocortical response of free‐ranging grizzly bears during capture.
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Affiliation(s)
- Marc Cattet
- RGL Recovery Wildlife Health & Veterinary Services, Saskatoon, SK, Canada.,Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - David M Janz
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada.,Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | | | - Joy A Erlenbach
- School of the Environment, Washington State University, Pullman, WA, USA
| | - Heiko T Jansen
- Department of Integrative Physiology and Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - O Lynne Nelson
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Charles T Robbins
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Gordon B Stenhouse
- fRI Research, Hinton, AB, Canada.,Alberta Environment & Parks, Edmonton, AB, Canada
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Pokharel SS, Yoneda H, Yanagi M, Sukumar R, Kinoshita K. The tail-tale of stress: an exploratory analysis of cortisol levels in the tail-hair of captive Asian elephants. PeerJ 2021; 9:e10445. [PMID: 33505782 PMCID: PMC7789861 DOI: 10.7717/peerj.10445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/07/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Assessment of physiological states by measuring biomarkers, such as cortisol, has significantly contributed to the monitoring of health, welfare and management of animals. Immunoreactive cortisol in hair (hC) has been used widely for deciphering 'stressful' past-events in various wild and captive animals. However, no such studies have been done in long-lived mammals. METHODS In this first exploratory study in elephants, we assessed (i) tail-hair growth rate (TGR) and (ii) hC levels in tail-hair samples from six captive Asian elephants from two zoos in Japan for comparing hC levels with zoo-keepers' records of distinct biological events over a c.0.5-2.0-year period. Tail-hair samples were cut into segments (based on monthly growth rate), pulverized or minced and a validated cortisol enzyme-immunoassay employed to measure hC levels. RESULTS When the hC levels of all individuals were compared with the keepers' records, a posteriori, most of the high hC levels were found to be associated with 'stressful' or distinct behavioural events such as pathological (anaemia, colic infection, skin infection, oral sores), psychosocial (reluctance in entering the enclosure, presence of a calf) and husbandry practice-related (contact trials/ space sharing) conditions, indicating that tail-hair indeed can be a potential 'retrospective' calendar of physiological health of an animal. CONCLUSIONS Our observations open up the possibility of using the tail-hair as an alternative matrix to reconstruct the physiological history of elephants.
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Affiliation(s)
- Sanjeeta Sharma Pokharel
- Wildlife Research Center, Kyoto University, Kyoto, Japan
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, Karnataka, India
| | | | - Moe Yanagi
- Wildlife Research Center, Kyoto University, Kyoto, Japan
| | - Raman Sukumar
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, Karnataka, India
- Institute for Advanced Study, Kyoto University, Kyoto, Japan
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