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Stead SM, Edwards PD, Persad R, Boonstra R, Teichroeb JA, Palme R, Bowman J. Coping with extreme free cortisol levels: Seasonal stress axis changes in sympatric North American flying squirrels. Gen Comp Endocrinol 2024; 349:114467. [PMID: 38342330 DOI: 10.1016/j.ygcen.2024.114467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/18/2024] [Accepted: 02/03/2024] [Indexed: 02/13/2024]
Abstract
Most environments exhibit predictable yearly changes, permitting animals to anticipate them. The hypothalamic-pituitary-adrenal (HPA) axis is a key physiological pathway that enables animals to cope with such changes. Monitoring glucocorticoid (the end products of the HPA axis) levels in wild animals throughout the year can improve our understanding of how this pathway responds to different conditions. For this study, we collected 18 months of data on two species of North American flying squirrels (Glaucomys sabrinus and G. volans) living in a southern Ontario forest where temperature and food availability fluctuate dramatically throughout the year. These squirrels are active year-round, nest communally, and rely on scatter hoarded foods in the winter months. Flying squirrels have extremely high levels of free plasma cortisol relative to other mammals, but it is unknown how these levels are affected by environmental and reproductive factors. For both species, our goals were to (1) validate an enzyme immunoassay (EIA) to measure their fecal glucocorticoid metabolite (FGM) concentrations and (2) assess yearly differences, seasonal changes, and the influence of sex, reproduction, and ambient temperature on FGM concentrations in each species. In the lab, we successfully validated the use of antibody 5α-pregnane-3β, 11β, 21-triol-20-one EIA for FGM analysis in both species. In the field, neither sex nor reproductive status (breeding condition or not) were linked to FGM concentrations in either species. FGM concentrations were higher in autumn compared to the spring and summer. There were no other seasonal differences. We discuss possible explanations for the autumn peak in FGM concentrations (increased energy expenditure and social nesting changes), as well as outline possible avenues for future research. Understanding how individuals and populations respond to environmental change is a critical goal in evolutionary ecology, particularly in the context of a rapidly changing Anthropocene.
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Affiliation(s)
- Samantha M Stead
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada.
| | - Phoebe D Edwards
- Department of Psychology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Rebekah Persad
- Environmental & Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Julie A Teichroeb
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Rupert Palme
- Department of Biological Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Jeff Bowman
- Environmental & Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada; Wildlife Research & Monitoring Section, Ontario Ministry of Natural Resources & Forestry, Trent University, Peterborough, Ontario, Canada
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Di Francesco J, Kwong GPS, Deardon R, Checkley SL, Mastromonaco GF, Mavrot F, Leclerc LM, Kutz S. Qiviut cortisol is associated with metrics of health and other intrinsic and extrinsic factors in wild muskoxen ( Ovibos moschatus). CONSERVATION PHYSIOLOGY 2022; 10:coab103. [PMID: 35492408 PMCID: PMC9040286 DOI: 10.1093/conphys/coab103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 10/03/2021] [Accepted: 12/27/2021] [Indexed: 05/21/2023]
Abstract
Glucocorticoid (GC) levels are increasingly and widely used as biomarkers of hypothalamic-pituitary-adrenal (HPA) axis activity to study the effects of environmental changes and other perturbations on wildlife individuals and populations. However, identifying the intrinsic and extrinsic factors that influence GC levels is a key step in endocrinology studies to ensure accurate interpretation of GC responses. In muskoxen, qiviut (fine woolly undercoat hair) cortisol concentration is an integrative biomarker of HPA axis activity over the course of the hair's growth. We gathered data from 219 wild muskoxen harvested in the Canadian Arctic between October 2015 and May 2019. We examined the relationship between qiviut cortisol and various intrinsic (sex, age, body condition and incisor breakage) and extrinsic biotic factors (lungworm and gastrointestinal parasite infections and exposure to bacteria), as well as broader non-specific landscape and temporal features (geographical location, season and year). A Bayesian approach, which allows for the joint estimation of missing values in the data and model parameters estimates, was applied for the statistical analyses. The main findings include the following: (i) higher qiviut cortisol levels in males than in females; (ii) inter-annual variations; (iii) higher qiviut cortisol levels in a declining population compared to a stable population; (iv) a negative association between qiviut cortisol and marrow fat percentage; (v) a relationship between qiviut cortisol and the infection intensity of the lungworm Umingmakstrongylus pallikuukensis, which varied depending on the geographical location; and (vi) no association between qiviut cortisol and other pathogen exposure/infection intensity metrics. This study confirmed and further identified important sources of variability in qiviut cortisol levels, while providing important insights on the relationship between GC levels and pathogen exposure/infection intensity. Results support the use of qiviut cortisol as a tool to monitor temporal changes in HPA axis activity at a population level and to inform management and conservation actions.
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Affiliation(s)
- Juliette Di Francesco
- Corresponding author: Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada.
| | - Grace P S Kwong
- Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada
- Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada
| | - Rob Deardon
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada
- Department of Mathematics and Statistics, Faculty of Science, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Sylvia L Checkley
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada
| | - Gabriela F Mastromonaco
- Reproductive Physiology Unit, Toronto Zoo, 361A Old Finch Avenue, Scarborough, Ontario M1B 5K7, Canada
| | - Fabien Mavrot
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada
| | - Lisa-Marie Leclerc
- Department of Environment, Government of Nunavut, P.O. Box 377, Kugluktuk, Nunavut X0B 0E0, Canada
| | - Susan 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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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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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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