Faecal Cortisol Metabolites as an Indicator of Stress in Captive Spotted Deer (Axis Axis) and Blackbuck (Antilope Cervicapra) in India.

Abstract

Wildlife is currently facing a lot of challenges in their natural ecosystem such as negative effect of anthropogenic activities and climate change. Zoos play an important role in conservation and protection of wildlife through education, captive breeding and research. However, while in the zoo’s wildlife is exposed to a different environment from their natural habitats and disturbances from human audience and climate variations. The aim of this study was to determine the effect of zoo visitor numbers, environmental factors (variation in Temperature Humidity Index during the October heat and winter season) and sex on faecal cortisol concentrations (ng/gm), as an indicator of stress levels in a captive population of blackbuck (Antilope cervicapra) and spotted deer (Axis axis) at Rajiv Gandhi zoological park in Pune, India. Assessment of adrenocortical activity through measurement of faecal glucocorticoid levels in faeces has significantly enabled data col-lection from wildlife, owing to its non-invasive nature. The blackbuck and spotted deer each con-sisted of six (6) adult males and six (6) adult females with an average age of 5.4 ± 0.55 and 5.5 ± 0.45 years respectively. The study animals were born and raised in the zoo. Each study animal was marked with ear tags for easy identification. The study was conducted in two (2) seasons during October heat (October-November) and winter (December-January). Visitor numbers was taken from the zoo records and temperature and humidity were measured every day using auto-matic hygrometer located in the zoo. Faecal sample collection was carried out between 12 noon to 6 pm on Wednesday (Low/Zero visitor category), Friday (Medium visitor category) and Sun-day (High visitor category) per week for three (3) weeks in each season. The faecal cortisol me-tabolites were determined using Radioimmunoassay method. The blackbuck faecal cortisol con- xvi centration was within a range of 0.18 ng/gm to 2.62 ng/gm while that of spotted deer was within a range of 0.18 ng/gm to 3.07 ng/gm. The faecal cortisol concentration in adult males and females were not significantly different in both seasons. Visitor numbers significantly affected faecal cor-tisol concentrations (ng/gm) of blackbuck during winter but not during October heat. Tempera-ture Humidity Index (THI) significantly affected the faecal cortisol metabolites in both blackbuck and spotted deer during winter but not during October heat. The observed differences in faecal cortisol concentrations (ng/gm) in blackbuck and spotted deer during winter are significant with negative correlation. The results of this study can be useful in informing management of captive wildlife and designing captive facility. Understanding the stress response of wildlife in captivity especially endangered ones is essential when planning for their effective conservation pro-grammes.