Validation of faecal glucocorticoid analysis in cheetahs (Acinonyx jubatus)

Abstract

Measurement of glucocorticoid metabolites in faeces is increasingly used as a non-invasive method for monitoring stress in wild animals. The aim of this study was to validate a non-invasive technique for monitoring adrenocortical activity in cheetahs (Acinonyx jubatus) by measuring glucocorticoid metabolites in the faeces before and after an adrenocorticotrophic hormone (ACTH) challenge. All faeces were collected from five cheetahs (two female and three male) ten days before and seven days after intramuscular injection of ACTH (50 IU). Samples were analyzed for glucocorticoid metabolite concentrations using an enzyme immunoassay (EIA). Faecal glucocortcoid metabolites increased 234 –715% above baseline within 20 hours of ACTH administration in all five cheetahs. When left at ambient temperature, faecal glucocorticoid metabolites concentrations declined over time since defaecation. Therefore it is advisable to freeze samples immediately after defaecation for reliable monitoring of faecal glucocorticoid metabolite concentrations. Our results show that non-invasive monitoring of faecal glucocorticoid metabolites can be a valid and useful tool for assessing adrenal activity in cheetahs.