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Kliphuis S, Manet MWE, Goerlich VC, Nordquist RE, Vernooij H, Tuyttens FAM, Rodenburg TB. Effects of lighted incubation and foraging enrichment during rearing on individual fear behavior, corticosterone, and neuroplasticity in laying hen pullets. Poult Sci 2024; 103:103665. [PMID: 38569241 PMCID: PMC10999657 DOI: 10.1016/j.psj.2024.103665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 03/07/2024] [Accepted: 03/12/2024] [Indexed: 04/05/2024] Open
Abstract
Environmental conditions during incubation and rearing can influence stress responsivity of laying hen pullets throughout their lifespan, and therefore have important implications for their welfare. In this study, a 12:12h green LED light-dark cycle during incubation and larvae provisioning as enrichment during rearing were tested as strategies to optimize early-life conditions and thereby decrease stress responsivity in ISA Brown laying hens. A combination of parameters was measured to indicate neuronal, physiological, and behavioral changes that may affect fear and stress. The proteins calbindin D28k (calbindin1), doublecortin (DCX), and neuronal nuclein protein (NeuN) were quantified after hatch as a proxy for brain plasticity. Plasma and feather corticosterone levels were measured after hatch and at the end of the rearing phase, and fearfulness was investigated through a series of behavioral tests (i.e., voluntary approach, open field, tonic immobility, and manual restraint tests). No effects of light during incubation were found on calbindin1, DCX, or NeuN. Neither of the treatments affected corticosterone levels in blood plasma and feathers. Light-incubated pullets showed less fearfulness towards humans in the voluntary approach test, but not in the other behavioral tests reported in this study. Larvae provisioning had no effect on behavior. Our study showed minor effects of light during incubation and no effects of enrichment during rearing on stress responsivity of laying hen pullets. The small effects may be explained by the enriched rearing conditions for all birds in this experiment (low stocking density, natural daylight, and 24/7 classical music). Given the promising results of lighted incubation in other studies, which were mostly performed in broiler chickens, and evidence regarding the positive effects of enrichment during rearing, the potential of these strategies to improve laying hen welfare needs to be explored further.
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Affiliation(s)
- Saskia Kliphuis
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
| | - Maëva W E Manet
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Vivian C Goerlich
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Rebecca E Nordquist
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Hans Vernooij
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Frank A M Tuyttens
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Merelbeke, Belgium; Department of Veterinary and Biosciences, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - T Bas Rodenburg
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands; Adaptation Physiology Group, Department of Animal Sciences, Wageningen University and Research, Wageningen, The Netherlands
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Kliphuis S, Manet MWE, Goerlich VC, Nordquist RE, Vernooij H, Brand HVD, Tuyttens FAM, Rodenburg TB. Early-life interventions to prevent feather pecking and reduce fearfulness in laying hens. Poult Sci 2023; 102:102801. [PMID: 37343352 PMCID: PMC10404761 DOI: 10.1016/j.psj.2023.102801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/16/2023] [Accepted: 05/18/2023] [Indexed: 06/23/2023] Open
Abstract
Severe feather pecking, the pulling out of feathers of conspecifics, is a major welfare issue in laying hens. Possible underlying causes are fearfulness and lack of foraging opportunities. Because early life is a crucial stage in behavioral development, adapting the incubation and rearing environment to the birds' needs may reduce fearfulness and prevent the development of feather pecking. In a 2 × 2 factorial design study, we investigated whether a green light-dark cycle throughout incubation, which resembles natural incubation circumstances more than the standard dark incubation, and foraging enrichment with live larvae during rearing reduce fearfulness and feather pecking and increase foraging behavior of laying hen pullets from an early age onwards. In this 2-batch experiment, 1,100 ISA Brown eggs were incubated under either 0 h of light/24 h of darkness or 12 h of green LED light/12 h of darkness. After hatching, 400 female chicks (200 per batch) were housed in 44 pens (8-10 chicks per pen). During the entire rearing phase (0-17 wk of age), half of the pens received black soldier fly larvae in a food puzzle as foraging enrichment. We assessed fear of novel objects and humans, feather pecking, plumage condition, foraging behavior, and recovery time after a 3-fold vaccination (acute stressor). A slight increase in the number of foraging bouts was only seen with larvae provisioning (rate ratio 1.19, 95% CI 1.02-1.29, P = 0.008). Neither lighted incubation nor larvae provisioning affected fearfulness, feather pecking, plumage condition or recovery time after vaccination. In conclusion, the present study showed no effects of light during incubation and minor effects of foraging enrichment during rearing on the behavior of laying hen pullets. Further research is recommended on other welfare aspects.
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Affiliation(s)
- Saskia Kliphuis
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
| | - Maëva W E Manet
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Vivian C Goerlich
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Rebecca E Nordquist
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Hans Vernooij
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Henry van den Brand
- Adaptation Physiology Group, Department of Animal Sciences, Wageningen University and Research, Wageningen, the Netherlands
| | - Frank A M Tuyttens
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Merelbeke, Belgium; Department of Veterinary and Biosciences, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - T Bas Rodenburg
- Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands; Adaptation Physiology Group, Department of Animal Sciences, Wageningen University and Research, Wageningen, the Netherlands
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Tiemann I, Fijn LB, Bagaria M, Langen EMA, van der Staay FJ, Arndt SS, Leenaars C, Goerlich VC. Glucocorticoids in relation to behavior, morphology, and physiology as proxy indicators for the assessment of animal welfare. A systematic mapping review. Front Vet Sci 2023; 9:954607. [PMID: 36686168 PMCID: PMC9853183 DOI: 10.3389/fvets.2022.954607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 12/12/2022] [Indexed: 01/07/2023] Open
Abstract
Translating theoretical concepts of animal welfare into quantitative assessment protocols is an ongoing challenge. Glucocorticoids (GCs) are frequently used as physiological measure in welfare assessment. The interpretation of levels of GCs and especially their relation to welfare, however, is not as straightforward, questioning the informative power of GCs. The aim of this systematic mapping review was therefore to provide an overview of the relevant literature to identify global patterns in studies using GCs as proxy for the assessment of welfare of vertebrate species. Following a systematic protocol and a-priory inclusion criteria, 509 studies with 517 experiments were selected for data extraction. The outcome of the experiments was categorized based on whether the intervention significantly affected levels of GCs, and whether these effects were accompanied by changes in behavior, morphology and physiology. Additional information, such as animal species, type of intervention, experimental set up and sample type used for GC determination was extracted, as well. Given the broad scope and large variation in included experiments, meta-analyses were not performed, but outcomes are presented to encourage further, in-depth analyses of the data set. The interventions did not consistently lead to changes in GCs with respect to the original authors hypothesis. Changes in GCs were not consistently paralleled by changes in additional assessment parameter on behavior, morphology and physiology. The minority of experiment quantified GCs in less invasive sample matrices compared to blood. Interventions showed a large variability, and species such as fish were underrepresented, especially in the assessment of behavior. The inconclusive effects on GCs and additional assessment parameter urges for further validation of techniques and welfare proxies. Several conceptual and technical challenges need to be met to create standardized and robust welfare assessment protocols and to determine the role of GCs herein.
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Affiliation(s)
- Inga Tiemann
- Faculty of Agriculture, Institute of Agricultural Engineering, University of Bonn, Bonn, Germany,*Correspondence: Inga Tiemann ✉
| | - Lisa B. Fijn
- Division of Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Marc Bagaria
- Division of Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Esther M. A. Langen
- Division of Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - F. Josef van der Staay
- Division of Farm Animal Health, Behaviour and Welfare Group, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Saskia S. Arndt
- Division of Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Cathalijn Leenaars
- Institute for Laboratory Animal Science, Hannover Medical School, Hanover, Germany
| | - Vivian C. Goerlich
- Division of Animals in Science and Society, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
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Nordquist RE, Vernooij J, Dull C, Pascual A, van der Linde G, Goerlich VC. The effects of transport of 18-day old hatching eggs on physiology and behaviour of slow growing broiler chicken. Appl Anim Behav Sci 2022. [DOI: 10.1016/j.applanim.2022.105789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Arndt SS, Goerlich VC, van der Staay FJ. A dynamic concept of animal welfare: The role of appetitive and adverse internal and external factors and the animal’s ability to adapt to them. Front Anim Sci 2022. [DOI: 10.3389/fanim.2022.908513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Animal welfare is a multifaceted issue that can be approached from different viewpoints, depending on human interests, ethical assumptions, and culture. To properly assess, safeguard and promote animal welfare, concepts are needed to serve as guidelines in any context the animal is kept in. Several different welfare concepts have been developed during the last half decade. The Five Freedoms concept has provided the basis for developing animal welfare assessment to date, and the Five Domains concept has guided those responsible for safeguarding animal welfare, while the Quality of Life concept focuses on how the individual perceives its own welfare state. This study proposes a modified and extended version of an earlier animal welfare concept - the Dynamic Animal Welfare Concept (DAWCon). Based on the adaptability of the animal, and taking the importance of positive emotional states and the dynamic nature of animal welfare into account, an individual animal is likely in a positive welfare state when it is mentally and physically capable and possesses the ability and opportunity to react adequately to sporadic or lasting appetitive and adverse internal and external stimuli, events, and conditions. Adequate reactions are elements of an animal’s normal behavior. They allow the animal to cope with and adapt to the demands of the (prevailing) environmental circumstances, enabling it to reach a state that it perceives as positive, i.e., that evokes positive emotions. This paper describes the role of internal as well as external factors in influencing welfare, each of which exerts their effects in a sporadic or lasting manner. Behavior is highlighted as a crucial read-out parameter. As most animals under human care are selected for certain traits that may affect their behavioral repertoire it is crucial to have thorough ethograms, i.e., a catalogue of specific behaviors of the species/strain/breed under study. DAWCon highlights aspects that need to be addressed when assessing welfare and may stimulate future research questions.
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Meijer E, Goerlich VC, van den Brom R, Giersberg MF, Arndt SS, Rodenburg TB. Perspectives for Buck Kids in Dairy Goat Farming. Front Vet Sci 2021; 8:662102. [PMID: 34722689 PMCID: PMC8554305 DOI: 10.3389/fvets.2021.662102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 09/15/2021] [Indexed: 11/19/2022] Open
Abstract
To start milk production, dairy goats need to give birth at least once. While most female kids are reared to become the next generation of dairy goats, only a small proportion of male kids (buck kids) are reared with reproduction aims. The market for buck kid meat, especially within Northern European countries, is currently relatively small compared to the number of bucks born. Therefore, the purposes for buck kids are limited and a substantial proportion of buck kid meat is used for pet food. Due to the limited economic value of buck kids, farmers are faced with a dilemma. Although raising bucks costs more money than it yields, the birth of kids is a prerequisite for production of milk and should be seen as an investment for business-wise healthy dairy goat farming. In that perspective, dairy goat farmers have an ethical responsibility toward buck kids, as well. In this paper, we compare various scenarios of dealing with the issue of surplus male animals. We provide recommendations for the rearing of buck kids based on the sector‘s experience and current practice in the Netherlands. Reducing the number of surplus (male) offspring, e.g., by an optimized prolonged lactation management and/or by artificial insemination with sex-sorted semen, could alleviate the issue of low value buck kids. Killing surplus animals before or directly after birth, on the other hand, is met with increasing societal scrutiny. Initiatives to propagate a market for buck kid meat for human consumption are important to enable a suitable and sustainable production system. To maintain the health and welfare of goat kids, amongst other factors, sufficient and good quality colostrum, milk, and an appropriate diet as they grow older, needs to be provided. One option to assure the safeguarding of health and welfare of all goat kids are quality assurance schemes for milk production. These schemes make dairy farmers accountable for the health and welfare of all kids in the rearing period, including the provision of colostrum and adequate care for newborn buck kids. We conclude that the combination of reducing the number of surplus kids, increasing the demand for goat products, and quality assurance schemes that may help to safeguard the welfare of buck kids.
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Affiliation(s)
- Ellen Meijer
- Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Vivian C Goerlich
- Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - René van den Brom
- Royal GD, Department of Small Ruminant Health, Deventer, Netherlands
| | - Mona F Giersberg
- Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Saskia S Arndt
- Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - T Bas Rodenburg
- Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
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Goerlich VC, Nätt D, Elfwing M, Macdonald B, Jensen P. Transgenerational effects of early experience on behavioral, hormonal and gene expression responses to acute stress in the precocial chicken. Horm Behav 2012; 61:711-8. [PMID: 22465454 DOI: 10.1016/j.yhbeh.2012.03.006] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 03/13/2012] [Accepted: 03/15/2012] [Indexed: 12/18/2022]
Abstract
Stress during early life can profoundly influence an individual's phenotype. Effects can manifest in the short-term as well as later in life and even in subsequent generations. Transgenerational effects of stress are potentially mediated via modulation of the hypothalamic-pituitary-adrenal axis (HPA) as well as epigenetic mechanisms causing heritable changes in gene expression. To investigate these pathways we subjected domestic chicken (Gallus gallus) to intermittent social isolation for the first three weeks of life. The early life stress resulted in a dampened corticosterone response to restraint stress in affected birds and in their male offspring. Stress-specific genes, such as early growth response 1 (EGR1) and corticotropin releasing hormone receptor 1 (CRHR1), were upregulated immediately after restraint stress, but not under baseline conditions. Treatment differences in gene expression were also correlated across generations which indicate transgenerational epigenetic inheritance. In an associative learning test early stressed birds made more correct choices suggesting a higher coping ability in stressful situations. This study is the first to show transgenerational effects of early life stress in a precocial species by combining behavioral, endocrinological, and transcriptomic measurements.
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MESH Headings
- Algorithms
- Animals
- Animals, Domestic
- Behavior, Animal/physiology
- Brain/metabolism
- Chickens/genetics
- Chickens/physiology
- Cohort Effect
- Female
- Gene Expression Regulation/physiology
- Male
- Models, Biological
- Physical Conditioning, Animal/methods
- Physical Conditioning, Animal/psychology
- Restraint, Physical/physiology
- Restraint, Physical/psychology
- Stress, Psychological/epidemiology
- Stress, Psychological/genetics
- Stress, Psychological/physiopathology
- Time Factors
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Affiliation(s)
- Vivian C Goerlich
- IFM Biology, Division of Zoology, Avian Behavioural Genomics and Physiology Group, Linköping University, Sweden
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Vergauwen J, Goerlich VC, Groothuis TGG, Eens M, Müller W. Food conditions affect yolk testosterone deposition but not incubation attendance. Gen Comp Endocrinol 2012; 176:112-9. [PMID: 22265816 DOI: 10.1016/j.ygcen.2012.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 01/03/2012] [Accepted: 01/04/2012] [Indexed: 11/24/2022]
Abstract
In many bird species with hatching asynchrony, yolk androgens increase across the laying sequence. This has been hypothesized to represent a compensatory mechanism for disadvantages of later-hatching chicks - via positive effects of yolk androgens on early competitiveness and growth. However, the costs and benefits of this compensatory strategy probably depend on environmental factors determining the survival chances of the chicks such as the food conditions, which should, therefore, influence maternal yolk androgen deposition. We studied the consequences of manipulated food conditions on the expected level of hatching asynchrony in canaries (Serinus canaria) assigning females to either a low (=LQ) or high quality (=HQ) diet. We measured the incubation behaviour (as incubation attendance) and the yolk androgen deposition in order to investigate whether and how females modulate hatching asynchrony in relation to the food conditions. Females on a HQ diet laid larger and heavier clutches, showed a stronger increase in yolk testosterone content towards the last-laid eggs, but did not alter their incubation attendance. Thus, females on a HQ diet seem to favour the survival of later hatching chicks, as indicated by their yolk testosterone deposition pattern. However, females on a HQ diet laid larger clutches and might need to compensate more in order to achieve a similar degree of hatching asynchrony than females on a LQ diet, given the lack of plasticity in incubation attendance. This suggests that canary females respond to food manipulations mainly via changes in clutch size rather than by altering the degree of hatching asynchrony.
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Affiliation(s)
- Jonas Vergauwen
- Department of Biology - Ethology, University of Antwerp, Universiteitsplein 1, 2610 Antwerp (Wilrijk), Belgium.
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Müller W, Goerlich VC, Vergauwen J, Groothuis TGG, Eens M. Sources of variation in yolk hormone deposition: consistency, inheritance and developmental effects. Gen Comp Endocrinol 2012; 175:337-43. [PMID: 22146794 DOI: 10.1016/j.ygcen.2011.11.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 10/25/2011] [Accepted: 11/21/2011] [Indexed: 10/15/2022]
Abstract
Maternal effects occur when the phenotype of the mother affects the phenotype of their offspring. They are thought to have evolved to translate the environmental conditions experienced by the mother into adaptive phenotypic variation of the offspring. However, the integration of environmental cues allowing adaptive responses requires some form of plasticity that depends on the interaction of the maternal phenotype and her environment. In birds, maternal yolk hormones represent such a pathway for maternal effects, and their adaptive significance depends thus on the plasticity in maternal yolk hormone deposition. We studied sources of variation in yolk testosterone deposition, focusing on the often neglected contribution of the (partly heritable) maternal phenotype. We investigated consistency and heritability of yolk testosterone deposition in captive canaries of which the F(1) generation was raised in foster nests and analyzed the potential effects of the early developmental conditions. We found significant female consistency across years in egg mass, yolk mass and total amount of yolk testosterone but not in yolk testosterone concentrations. Females varied the yolk testosterone concentrations of their eggs across years mainly via changes in yolk mass. The heritable variation in egg mass, yolk mass and amount of yolk testosterone but not yolk testosterone concentrations was within the range of previous studies, but not significantly different from zero. Finally, the growth of the daughters as nestling had a significant effect on their yolk testosterone deposition at adulthood indicating the transgenerational potential for environmental effects - via the effects of yolk hormones on offspring development.
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Affiliation(s)
- Wendt Müller
- Department of Biology-Ethology, University of Antwerp, Belgium.
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Dijkstra C, Riedstra B, Dekker A, Goerlich VC, Daan S, Groothuis TGG. An adaptive annual rhythm in the sex of first pigeon eggs. Behav Ecol Sociobiol 2010; 64:1393-1402. [PMID: 20730075 PMCID: PMC2920424 DOI: 10.1007/s00265-010-0954-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 03/29/2010] [Accepted: 04/01/2010] [Indexed: 11/03/2022]
Abstract
When the reproductive value of male and female offspring varies differentially, parents are predicted to adjust the sex ratio of their offspring to maximize their fitness (Trivers and Willard, Science 179:90-92, 1973). Two factors have been repeatedly linked to skews in avian offspring sex ratio. First, laying date can affect offspring sex ratio when the sexes differ in age of first reproduction, such that the more slowly maturing sex is overproduced early in the season. Second, position of the egg in the laying sequence of a clutch may affect sex ratio bias since manipulating the sex of the first eggs may be least costly to the mother. We studied both factors in two non-domesticated pigeon species. Both the Wood pigeon (Columba palumbus) and the Rock pigeon (Columba livia) have long breeding seasons and lay two-egg clutches. In the field, we determined the sex of Wood pigeon nestlings. In Rock pigeons, housed in captivity outdoors, we determined embryo sex after 3 days of incubation. On the basis of their sex-specific age of first reproduction, we predicted that males, maturing at older age than females, should be produced in majority early and females later in the year. This was confirmed for both species. The bias was restricted to first eggs. Rock pigeons produced clutches throughout the year and show that the sex of the first egg followed an annual cycle. To our knowledge, this study presents the first evidence of a full annual rhythm in adaptive sex allocation in birds. We suggest that this reflects an endogenous seasonal program in primary sex ratio controlled by a preovulatory mechanism.
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Affiliation(s)
- Cor Dijkstra
- Behavioural Biology, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands
| | - Bernd Riedstra
- Behavioural Biology, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands
| | - Arjan Dekker
- Behavioural Biology, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands
| | - Vivian C. Goerlich
- Behavioural Biology, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands
| | - Serge Daan
- Behavioural Biology, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands
| | - Ton G. G. Groothuis
- Behavioural Biology, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands
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Goerlich VC, Dijkstra C, Groothuis TGG. Effects of in vivo testosterone manipulation on ovarian morphology, follicular development, and follicle yolk testosterone in the homing pigeon. ACTA ACUST UNITED AC 2010; 313:328-38. [DOI: 10.1002/jez.600] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Goerlich VC, Dijkstra C, Schaafsma SM, Groothuis TGG. Testosterone has a long-term effect on primary sex ratio of first eggs in pigeons--in search of a mechanism. Gen Comp Endocrinol 2009; 163:184-92. [PMID: 19344666 DOI: 10.1016/j.ygcen.2009.01.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Revised: 12/18/2008] [Accepted: 01/13/2009] [Indexed: 11/19/2022]
Abstract
Despite accumulating evidence that birds, in which females are the heterogametic sex, are able to manipulate primary offspring sex ratio, the underlying mechanism remains elusive. Steroid hormones, which govern female reproduction and are also accumulated by the developing follicle could potentially affect primary sex ratio by differential follicle development in relation to future sex and meiotic drive, or by sex specific influence on oocyte abortion or fertilization. So far, experimental results on the involvement of maternal testosterone (T) in offspring sex manipulation are ambiguous. To investigate the effect of T on primary sex ratio and elucidate underlying mechanisms, we elevated circulating T levels in female homing pigeons (Columba livia). During the course of the experiment females produced three clutches--before and during T implantation, and one year after implant removal. Intriguingly, first eggs, but not second eggs of T females were significantly male biased relative to sham-implanted controls. One year after cessation of the treatment the male bias was still present, indicating long-term effects on female reproductive physiology. T treatment did not affect maternal body condition, nor was body condition correlated with offspring sex ratio. Our data on timing of oviposition, lack of infertile eggs, and yolk weight indicate a possible role for sex specific follicle abortion, perhaps in combination with meiotic drive. However, despite T treatment elevating maternal plasma levels, egg yolk T concentrations did not differ between treatment groups and did not vary with embryo sex, suggesting that yolk T is not involved in meiotic drive.
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Affiliation(s)
- V C Goerlich
- Behavioral Biology, University of Groningen, Kerklaan 30, P.O. Box 14, 9750 AA Haren, The Netherlands.
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