Dissertation/Thesis Abstract

Assessment of adrenal activity and reproductive cycles during captive management in the fishing cat (Prionailurus viverrinus)
by Fazio, Jilian M., Ph.D., George Mason University, 2016, 224; 10140296
Abstract (Summary)

Fishing cats (Prionailurus viverrinus) are a small felid found primarily throughout Southeast Asia. Wild populations have been rapidly dwindling due to degradation and loss of habitat along with retribution killings. Captive populations have been established throughout the world to help ensure this species persists. In North America, Species Survival Programs (SSP) are committees formed within the Association of Zoos and Aquariums (AZA) to help manage captive populations of threatened and endangered species. The SSPs are made up of a group of species-specific experts dedicated to sustaining a healthy captive population that can serve to educate the public and potentially replenish dwindling wild populations if needed in the future. The SSPs make breeding recommendations for each species based on genetics, age and keeper intuition. Often because of a genetically valuable animal’s age, there is only one chance to create a successful breeding pair. It was hypothesized that individual fishing cats would differ in their adrenocorticol response during transfer between institutions and during breeding introductions. The prediction was that glucocorticoid levels would have a direct correlation with the manner in which the individuals are managed and overall breeding success.

The study ultimately had four objectives: 1. Examine the current management and breeding behaviors of captive fishing cats. 2. Validate a glucocorticoid assay for longitudinal monitoring of exogenous stressors on adrenocortical activity in males and females. 3. Determine relationship between adrenal activity and gonadal function in females. 4. Characterize temperament within the population and correlate with behavioral traits, breeding success and adrenal activity.

The study ran from 2010-2013 monitoring 27 (13 male; 14 female) fishing cats at 17 institutions which included 15 unique breeding pairs and 20 transfers (13 males, 7 females), which occurred primarily in the fall (62%). Validation of a single antibody cortisol enyzme immunoassay (R4866 supplied by C.J. Munro, University of California, Davis, CA, USA) was performed using standard assay validation. In addition, an adrenocorticotropin challenge revealed peak glucocorticoids metabolites (GCM) occur approximately 21 hours after adrenal stimulation. Longitudinal monitoring revealed significant elevations in GCM concentrations during institutional transfers lasting 54 ± 16 days indicating most individuals take at least three months to settle into a new facility after translocation. Most initial physical breeding introductions during this study (83%) occurred within that timeframe. Mate compatibility seems rigid with pairs copulating between 39-289 days after quarantine release, or not at all, indicating a one year trial period for pairs is sufficient to determine potential breeding success. Increases 4-10x in baseline GCM concentrations were observed during periods of chronic illness (i.e. hepatitis) and therefore could be used to help diagnose acute health concerns in this species.

Reproductive activity occurred throughout the year and was not impacted by institutional transfers. Natural pregnancies (n = 5) all occurred March-July and 67% of females exhibited one or more periods of anestrus lasting 66-181 days beginning most often April-August (67%). Highest mean progestogen and estrogen concentrations occurred between December and August. Differences in peak estrogens, occurring approximately 8 days (range 0-30) into non-pregnant luteal phases (NPLP) and 40 days (range 32-49 days) into a pregnancy may help distinguish the two. A high percentage of females (58%) exhibited spontaneous ovulation during the study period with no clear ovulation mechanism. Ovulation may be influenced by age or induced by external stimuli, other than intromission during copulation - such as semiochemicals detected in shared enclosure spaces or tactile contact through mesh enclosures. The species high reliance on aquatic habitats also may lend itself to resource dependant stimulation of the hypothalamus pituitary gonadal axis, such as annual rainfall or access to large pools of water, which bears further investigation.

Recommendations include transfers in the late spring or early summer of males allowing at least three months post quarantine release for physical introductions, to allow the tranferred individual time to return to baseline GCM concentrations before experiencing another stressful event (breeding introductions). Institutions with breeding pairs can improve breeding success via reducing fishing cat stress levels with positive animal keeper interaction through training and providing indoor off-exhibit refuge areas. It is also suggested that videotaping breeding introductions and providing at least 1-2 nest boxes for females may all contribute to greater captive breeding success in the fishing cat.

The information gained by this study provides an outline for fishing cat SSP managers on how this species is managed in captivity. It also provides a solid foundation of longitudinal monitoring of adrenal activity and provides recommendations for the future sustainability of the ex situ population. (Abstract shortened by ProQuest.)

Indexing (document details)
Advisor: Parsons, E. Christien
Commitee: Bauer, Erika, Freeman, Elizabeth, Rockwood, Larry
School: George Mason University
Department: Environmental Science and Public Policy
School Location: United States -- Virginia
Source: DAI-B 77/11(E), Dissertation Abstracts International
Subjects: Ecology, Endocrinology, Zoology, Animal sciences
Keywords: Adrenal activity, Captive managment, Felid, Felid reproduction, Fishing cat, Reproductive behavior
Publication Number: 10140296
ISBN: 978-1-339-95715-9
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