Non-invasive assessment of adrenocortical endocrine function in African wild dogs (Lycaon pictus) by measurement of glucocorticoid metabolites in faeces.

Abstract

Non-invasive techniques for monitoring stress in wild animals have been studied extensively over the past two decades. The aim of this study was to use an adrenocorticotrophic hormone challenge to validate the measurement of glucocorticoid metabolite concentrations in faeces with an ELISA assay as a means of monitoring adrenocortical activity in African wild dogs (Lycaon pictus). Faecal samples were collected from four study animals for ten days prior to, and seven days after, an injection with 50 IU ACTH (Synacthen®, Novartis RSA (Pty) Ltd, Kempton Park South-Africa). Samples were analyzed for glucocorticoid metabolite concentrations using a Cortisol-3-CMO enzyme immunoassay and a 3α,11-Oxo-etiocholanolone enzyme immunoassay. The Cortisol EIA showed an increase in glucocorticoid metabolites of 263%-325% post ACTH administration, whereas a 3α,11-Oxo-CM EIA showed an increase of only 125%-139%. These results suggest that the Cortisol EIA is more sensitive and suitable for monitoring adrenocortical activity in African wild dogs than the 3α,11-Oxo-CM EIA. However since not all animals showed a response using the Cortisol EIA, further research is necessary to fully validate this technique.