Special Issue "Non-invasive Methods of Stress Monitoring in Animals under Human Care"
A special issue of Animals (ISSN 2076-2615). This special issue belongs to the section "Wildlife".
Deadline for manuscript submissions: 30 November 2021.
Special Issue Editors
Interests: stress physiology; reproductive physiology; conservation biology; endangered species
Interests: reproduction; elasmobranchs; ungulates; spermatozoa; cryopreservation; endocrinology; zoo; wildlife
Special Issue Information
Dear Colleagues,
Understanding the stress physiology of animals under human care is vital to their management and the designing of informative research. As humans continue to negatively impact the planet, wildlife species are increasingly under threat due habitat loss and degradation. Ex situ populations are now under more pressure to be successful, but unfortunately, that is not typically case. To better understand how the human-managed environment is impacting wildlife, it is imperative to develop non-invasive techniques that will allow sampling without influencing the individual’s stress physiology. By conducting observational research along with non-invasive sampling to evaluate physiology, we can better understand and modify our management of wildlife. This will lead to their population success and provide a haven for imperilled wildlife.
Original manuscripts that address non-invasive tools to evaluate wildlife stress physiology are invited for this Special Issue. Topics of special interest include innovative techniques for evaluating wildlife stress physiology, integrated behavioural and endocrinological research on wildlife under human care, and developing methods to evaluate not just stress hormones, but stress responses, to better understand the role of captive management on wildlife success.
Dr. Rachel Santymire
Dr. Linda M Penfold
Guest Editors
Manuscript Submission Information
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Animals is an international peer-reviewed open access monthly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.
Keywords
- glucocorticoids
- wildlife
- stress
- hormones
- stress responses
- under human care, ex situ
Planned Papers
The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.
Title: Validating the use of dermal swabs in the marine sunfish (Mola mola) to monitor their stress physiology
Authors: RM Santymire; KJ Fowler; M. Murray
Affiliation: Georgia State University
Abstract: The marine sunfish (Mola mola) is the heaviest bony fish in the world. This slow-moving fish often is injured by fishing boats that use drift gillnets attributing to its listing as Vulnerable by the IUCN. The Monterey Bay Aquarium (California, USA) has a program, which brings in smaller Mola from the ocean and acclimates them for exhibit. When they grow too large for the million-gallon Open Seas exhibit, they are returned to the Bay through a “reverse” acclimatization. Our goal was to use dermal swabs to evaluate Mola stress physiology to better understand the effects of this program. Our objectives were to validate this method by taking opportunistic swabs throughout acclimatization and during stressful events. We swabbed each individual (n=10) in three different body locations. Swabs were analyzed using a cortisol (Munro R4866) enzyme immunoassay. We averaged the three swabs and examined the change from baseline in cortisol during treatments and these different acclimation stages, from treatment pool behind the scenes, to the exhibit, Animal Research and Care Center (an off-site holding facility) and back to the Bay. Overall, mean (± SEM) cortisol varied (P<0.05) among individuals (476.9 ± 106.4 pg/mL). Cortisol tended to increase (P>0.05) from admittance (169.5 ± 77.8 pg/mL) to 1-week in the acclimation process (307.6 ± 57.3 pg/mL) and during transportation (890.4 ± 581.6 pg/mL). However, cortisol significantly increased (P<0.05) when the Mola were being treated for an illness (1697.8 ± 825.8 pg/mL). Although dermal cortisol varied among individuals, we did observe an increase during times that were considered stressful events. This is the first step in validating the use of dermal swabs in Mola. Further biochemical analysis is needed to determine the specific steroids that are being measured to ensure that the changes in cortisol are a true reflection in Mola stress physiology.
Title: Stress hormone concentrations influence complex problem solving in the fawn-footed mosaic-tailed rat Melomys cervinipes
Authors: Misha K. Rowell1 2*; Rachel M. Santymire 3; Tasmin L. Rymer 1,2
Affiliation: 1. College of Science and Engineering, James Cook University, P. O. Box 6811, Cairns, QLD 4870, Australia 2. Centre for Tropical Environmental and Sustainability Sciences, James Cook University, P. O. Box 6811, Cairns, QLD 4870, Australia 3. Biology Department, Georgia State University, Atlanta, GA, USA
Abstract: Environmental change is a major global concern, putting many species at risk of extinction. To cope with these challenges, animals must respond with appropriate physiological changes, particularly of glucocorticoid hormones, which then affect appropriate behavioural and cognitive responses. While the influence of glucocorticoids on laboratory animal behaviour and cognition is well documented, how physiological processes influence behaviour and cognition in native animals is poorly understood. Therefore, we investigated whether baseline corticosterone metabolite concentration influenced problem solving performance in a native Australian rodent, the fawn-footed mosaic-tailed rat Melomys cervinipes. We measured problem solving using two food-baited puzzles boxes presented in the home cages (cardboard matchbox and a plastic cylinder), a food-baited activity board with puzzles of differing complexity (two pillars to push, two tiles to slide and two levers to lift) in an open field arena, and an escape-motivated obstruction task in a light/dark box. Faecal samples were collected from each individual during routine cage cleaning. The corticosterone metabolite concentration of each sample was analysed using corticosterone enzyme-linked immunosorbent assay (ELISA). We found that corticosterone metabolite concentration only significantly influenced problem solving success in the most complex task (the tile task), with individuals that had higher corticosterone concentrations solving the problem faster than individuals with lower concentrations. Higher long-term corticosterone concentration could be indicative of a reactive personality type or positive stimulation by environmental conditions, both of which could affect how individuals gather information. Future studies should consider investigating how short-term measures of physiological condition influence problem solving ability.
Title: Longitudinal Monitoring of Adrenal Activity of Orangutans during Temporary Changes in Housing and Visitor Exposures
Authors: Fink, L.; Mukobi, A.; Jackson, S.; Reed, C.; VanBeek, B.; N. Wielebnowski
Affiliation: Oregon Zoo, Portland, United States
Abstract: From May 2018 – December 2020, three orangutans (1.1 P. p. pygmaeus & 0.1 P. abelii) housed at the Oregon Zoo were moved to the Veterinary Medical Center (VMC) to allow an exhibit remodel of the primate facility. This resulted in over two years without visitor interactions. Using a double-antibody corticosterone enzyme immunoassay (EIA) (CMJ006, UC Davis), fecal glucocorticoid metabolite (fGM) concentrations were monitored three times per week for the duration of the housing change and subsequent reintroduction to the completed habitat. Additionally, end-of-life fGM concentrations were monitored opportunistically for one orangutan (Inji). There were slightly more variable seasonal fGM concentration differences while the orangutans were housed at VMC. Furthermore, there was a decrease in average fGM concentrations in the three months before Inji passed away. In the months since the orangutans were reintroduced to visitors, the remaining orangutan fGM concentrations have remained consistently lower than the values measured when housed at VMC.
Title: Reproductive and adrenal physiology of dwarf mongoose in relation to social changes
Authors: Candace D. Scarlata; Becca VanBeek; Laura A. Weiner; Virginia Grimley; Anne M. Lauerman; Nadja C. Wielebnowski
Affiliation: Oregon Zoo, Portland, United States
Abstract: Dwarf mongooses (Helogale parvula) are cooperative breeders that live in groups with a dominance hierarchy among same sex individuals. A small colony of this species is kept at the Oregon Zoo. Animal keepers had noticed some increased aggression and possible shifts in dominance among the females. To better understand these changes and help with future management, we decided to monitor reproductive and adrenal hormones. Previous hormone research for this species has focused on urine analyses using RIA assays and found that dominant females had higher estrogen and glucocorticoid levels than subordinates. The objectives of this study were: 1) Validate fecal hormone metabolite enzymeimmunoassays in male and female dwarf mongoose; 2) determine whether social status affects hormone excretion; 3) characterize hormonal changes associated with reproduction and breeding. Fecal samples were collected every other day from 5 (1.4) animals for 5-24 months. For each sample, 0.250 g of dried feces was combined with 5 ml 80% methanol, shaken on a rotator overnight, centrifuged for 15 minutes and the supernatant was stored at -20⁰C until analysis. Female samples were analyzed for fecal progestagens and estrogens and female and male samples were analyzed for glucocorticoid metabolites using EIA techniques. All 5 animals showed a large spike in glucocorticoids the day after the new male was introduced to the group, which provides support for a biological validation of our glucocorticoid assay. Our data support previous findings in which the dominant female showed higher estrogen and glucocorticoid values than subordinate females. In addition, we monitored progestagen concentrations for the first time in this species. Females showed cyclic progestagen changes every 41-51 days. The cycle consisted of 26-30 days of elevated progestagens followed by 14-22 days of low progestagens. These data suggest that dwarf mongooses may be spontaneous ovulators, which is contrary to assumptions published in other studies.
Title: Non-invasive quantification of faecal reproductive and stress-related hormone metabolites in the naked mole-rat (Heterocephalus glaber)
Authors: T. L. Majelantle1*, N. C. Bennett1, D. Hart1, A. Ganswindt1,2
Affiliation: 1Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria 2Biodiversity Research Services, National Zoological Gardens, South Africa
Abstract: Small size in some mammals, such as the naked mole-rat (Heterocephalus glaber), restricts long-term and frequent monitoring of endocrine function using blood. Thus, non-invasive monitoring of faecal hormone metabolites could prove invaluable. The aim of the present study was to examine the suitability of enzyme-immunoassays (EIAs) for monitoring reproductive function and responses to stressors in naked mole-rats using faeces as a hormone matrix. A saline control administration, a gonadotrophin-releasing hormone challenge, and an adrenocorticotropic hormone challenge were performed on six male and six female disperseral morph naked mole-rats. Preliminary results revealed that an Epiandrosterone EIA utilizing antibodies against 5-androstan-3-ol-17-on-HS-BSA, a Progesterone EIA utilizing antibodies against 5-pregnan-3β-ol-20-one-3-HS-BSA, and a Cortisol EIA utilizing antibodies against cortisol-3-CMO:BSA resulted in the highest post-challenge responses in naked mole-rats. Females showed consistently higher faecal androgen, progestagen, and glucocorticoid metabolite baseline and peak values compared to males, indicating potential sex differences in steroid metabolism and reproductive suppression mechanisms. The results highlight enzyme-immunoassays as a powerful tool to monitor reproductive function and responses to stressors in faeces of naked mole-rats, which is valuable for their housing, welfare and further research.
Title: Effects of positive-reinforcement-training and novel-object exposure on salivary cortisol levels under consideration of inter-individual variation in captive African elephants (Loxodonta africana)
Authors: Susan Hambrecht 1,2*; Ann-Kathrin Oerke 3; Michael Heistermann 3; Johannes Hartig 4; Paul W. Dierkes 2
Affiliation: 1 Magdeburg Zoo, Zooallee 1, 39124 Magdeburg, Germany. 2 Bioscience Education and Zoo Biology, Goethe-University Frankfurt, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany 3 Endocrinology Laboratory, German Primate Centre, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany 4 Educational Measurement, Educational Quality and Evaluation, Leibniz-Institute for Research and Information on Education, Rostocker Straße 6, 60323 Frankfurt am Main * Correspondence: [email protected] (Susan Hambrecht)
Abstract: Dealing with potential stress in species that have high husbandry requirements, such as the African elephant, is a challenge for zoos. The present study aimed to find out how positive-reinforcement-training (PRT) and presentation of a novel-object (NOV) for enrichment affects the physiological stress level and which factors determine inter-individual variation in this regard in captive African elephants. We repeatedly sampled saliva of ten animals (three zoos) for analysis of cortisol (SACort) before and up to 60 min (in 10-15 min intervals) after the onset of PRT or NOV, which lasted 10 min. There was considerable individual variation in SACort in response to PRT or NOV. Using mixed models, we were able to control these and to reveal that PRT had a cortisol-lowering effect, while NOV induced a moderate SACort increase. Inter-individual differences in SACort were related to age and sex (NOV), while the effects of zoo, handling method (free vs. protected contact) and social status were variable. We conclude that PRT and NOV had differential effects on SACort, which we consider positive in terms of stress coping. In addition, understanding the individuality of stress will support management decisions aimed at promoting captive elephant welfare.