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Clarke E, Heugten KAV, Tollefson TN, Ridgley FN, Smith D, Brown JL, Scott H, Minter LJ. Comparison of Corticosterone Concentrations in Dermal Secretions and Urine in Free-Ranging Marine Toads ( Rhinella marina) in Human Care. Vet Med Int 2023; 2023:1467549. [PMID: 37766874 PMCID: PMC10522434 DOI: 10.1155/2023/1467549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 08/25/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Corticosterone concentrations have been measured in amphibians by collecting blood or urine samples. However, blood sampling is invasive, and urine can be difficult to collect. A novel method of swabbing the skin of an amphibian has been utilized in numerous species but has not been verified in marine toads (Rhinella marina). This pilot study tested dermal swabs as a noninvasive method for collecting and measuring dermal corticosterone secretions. Swabs were used to collect dermal secretion samples from sixty-six free-ranging marine toads collected on Zoo Miami grounds. The subsequent day the toads were shipped to the North Carolina Zoo where dermal samples were collected again. Additional dermal and urine samples were collected on days 9, 15, 32, and 62 under human care to measure corticosterone concentrations. There was no significant correlation (P ≥ 0.05) noted between corticosterone concentrations reported in dermal swabs and those in urine samples at all four of the euthanasia time points or between the corticosterone concentrations reported in either urine or dermal swabs and the weight of the toads. Dermal swab concentrations (ng/mL) were significantly higher (P ≤ 0.05) on the day of capture (0.64 ± 0.03) and the day of arrival (0.67 ± 0.03) than on day 15 (0.47 ± 0.03). The urine corticosterone concentrations decreased while the toads were in human care with a significant decrease (P ≤ 0.05) between days 9 (0.45 ± 0.07) and 32 (0.21 ± 0.06). This study demonstrated that dermal swabs can be used to collect marine toad corticosterone concentration samples.
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Affiliation(s)
- Emma Clarke
- Department of Clinical Sciences, North Carolina State University, College of Veterinary Medicine, 1060 William Moore Dr., Raleigh, NC 27607, USA
| | - Kimberly Ange-van Heugten
- Department of Animal Science, North Carolina State University, 120 W. Broughton Dr., Raleigh, NC 27695, USA
- Environment Medicine Consortium, North Carolina State University, 1060 William Moore Dr., Raleigh, NC 27607, USA
| | - Troy N. Tollefson
- Mazuri® Exotic Animal Nutrition, PMI Nutrition, 4001 Lexington Ave. North, Arden Hills, MN 55126, USA
| | - Frank N. Ridgley
- The Conservation and Research Department, Zoo Miami, 12400 SW 152nd St., Miami, FL 33177, USA
| | - Dustin Smith
- North Carolina Zoo, 4401 Zoo Pkwy, Asheboro, NC 27205, USA
| | - Janine L. Brown
- Smithsonian Conservation Biology Institute, 1500 Remount Rd., Front Royal, VA 22630, USA
| | - Heather Scott
- North Carolina Zoo, 4401 Zoo Pkwy, Asheboro, NC 27205, USA
| | - Larry J. Minter
- Department of Clinical Sciences, North Carolina State University, College of Veterinary Medicine, 1060 William Moore Dr., Raleigh, NC 27607, USA
- Environment Medicine Consortium, North Carolina State University, 1060 William Moore Dr., Raleigh, NC 27607, USA
- North Carolina Zoo, 4401 Zoo Pkwy, Asheboro, NC 27205, USA
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Santymire RM, Young M, Lenihan E, Murray MJ. Preliminary Investigation into Developing the Use of Swabs for Skin Cortisol Analysis for the Ocean Sunfish (Mola mola). Animals (Basel) 2022; 12:ani12202868. [PMID: 36290254 PMCID: PMC9597772 DOI: 10.3390/ani12202868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/09/2022] [Accepted: 10/19/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Zoos and aquaria play an important role in preventing the mass extinction of wildlife through public awareness of conservation issues and providing a safe haven for wildlife populations. Because aquatic populations face many challenges due to pollution and global warming, it is important to develop an understanding of how species can cope with their environment whether it be in the wild or under human care. Here, we were interested in developing non-invasive methods to study fish stress physiology. We use the unique ocean sunfish (Mola mola) to develop the use of skin swabs to measure the stress hormone, cortisol. We used known times of stress including when a mola was injured or ill and during acclimation to the Monterey Bay Aquarium. We found that cortisol increased initially within the first month of being admitted to the aquarium, but returned to normal values afterward. Molas also had elevated cortisol when being treated for an injury or illness. This is the first step in the development of the use of skin swabs to collect samples for stress analysis in the mola. Additional biochemical analysis is needed to confirm these results and allow this method to be applied to other species of fish. Abstract The ocean sunfish (mola; 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 (Monterey, CA, USA) has a program that brings in smaller molas from the ocean and acclimates them for an exhibit. When they grow too large for the million-gallon Open Seas exhibit, they are returned to Monterey Bay through a “reverse” acclimatization. Our overall goal was to use skin swabs to evaluate mola stress physiology to better understand the effects of this program. Our objectives were to validate this non-invasive method by taking opportunistic swabs throughout acclimatization and during stressful events. We swabbed each individual (n = 12) in three different body locations. Swabs were analyzed using a cortisol enzyme immunoassay. We averaged the three swabs and examined the absolute change of cortisol from the first taken upon handling to during treatments and the different acclimation stages. We considered elevated cortisol concentrations to be ≥1.5-fold higher than the first sample. Overall, mean (±SEM) cortisol varied among individuals (564.2 ± 191.5 pg/mL swab (range, 18.3–7012.0 pg/mL swab). The majority (four of six) of molas swabbed within the first week or month had elevated skin cortisol compared to their first sample. All seven molas that were being treated for an injury or illness had elevated skin cortisol (range, 1.7- to 127.6-fold higher) compared to their post-acclimation sample. This is the first step in validating the use of non-invasive skin swabs for glucocorticoid analysis in the mola. Further biochemical analysis is needed to determine the specific steroids that are being measured.
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Affiliation(s)
- Rachel M. Santymire
- Biology Department, Georgia State University, 100 Piedmont Ave SE, 4th Floor, Atlanta, GA 30303, USA
- Correspondence:
| | - Marissa Young
- Veterinary Services, Monterey Bay Aquarium, 886 Cannery Row, Monterey, CA 93940, USA
| | - Erin Lenihan
- Veterinary Services, Monterey Bay Aquarium, 886 Cannery Row, Monterey, CA 93940, USA
| | - Michael J. Murray
- Veterinary Services, Monterey Bay Aquarium, 886 Cannery Row, Monterey, CA 93940, USA
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