Abstract: Monitoring adrenocortical activity using fecal hormonal analysis can provide information on how environmental changes are affecting non-domestic species health and success in the field; however, this noninvasive method needs proper validation to ensure that analysis reflects true physiological events. Our objectives were to use adrenocorticotropic hormone (ACTH) challenges as a physiological validation method to test the suitability of a new corticosterone enzyme immunoassay (EIA) to accurately assess the adrenocortical activity using fecal samples in four African wildlife species-the black rhinoceros (rhino; Diceros bicornis), African elephant (Loxodonta africana), chimpanzee (Pan troglodytes) and African lion (Panthera leo krugeri). In the rhino and elephant, fecal Glucocorticoid metabolites (GC) surged 75 and 51 h post-ACTH injection, respectively. In the chimpanzee, fecal GC metabolites peaked at 29 h post-injection. And the lion had a peak of fecal GC at 24 h post-ACTH. This study determined that adrenocortical activity was reflected in concentrations of fecal GC metabolites suggesting that this corticosterone EIA is an effective technique for the monitoring stress in four African species
