Evaluation of using non-invasive fecal sampling to assess hormonal profiles in siamangs.

Abstract

Introduction: The population of siamangs is declining and current captive breeding programs have limited success. Non-invasive endocrine metabolite analysis is becoming an increasingly popular technique to monitor the reproductive status of mammals in conservation endocrinology. Several different extraction and quantification methods have been established for new species. Currently, the hormonal profile of siamangs at preconception, during gestation, throughout the onset of labour and post parturition is not known. Aims: 1. To evaluate whether commercially available ELISA kits can be used to effectively measure reproductive hormones in siamangs. 2. To determine the temporal changes in these hormones across gestation using fecal samples. Methods: The study used fecal samples retrospectively collected from a female siamang (Kera) over a period of 11 months living at Auckland Zoo. Various commercially available ELISA kits were utilised to assess the suitability of these kits to measure the profiles of corticosterone, estradiol, progesterone and corticotropin releasing hormone in the collected fecal samples during Kera’s pregnancy and post-partum. Results: The results showed that it is possible to utilise commercially available ELISA kits developed for general use (corticosterone and progesterone), specifically monkeys (estradiol) or humans (corticotropin releasing hormone), in siamangs. The CRH assay did not pass the quality threshold, so interpretations could not be made. Estradiol and progesterone profiles followed a significant temporal pattern observed in other primates, across gestation. Behavioural and observation data imply that corticosterone levels can spike in response to stress in siamangs in captivity. Conclusion: This is the first study to perform non-invasive endocrine analysis on siamangs throughout gestation. Combining behavioural measurements with this physiological data can improve captive breeding outcomes and increase the chance of establishing a self – sustaining captive siamang populations. Despite the sample size of one, this study provides valuable novel information regarding fecal endocrine profiling to monitor the reproductive health of siamangs. This will assist future research within captive breeding programs and augment the collective effort of conservation endocrinology.