Validation of noninvasive monitoring of adrenocortical endocrine activity in ground-feeding aardwolves (Proteles cristata): Exemplifying the influence of consumption of inorganic material for fecal steroid analysis
Physiological and Biochemical Zoology
Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa; Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa; Department of Equine Sciences, Faculty of Veterinary Science, Utrecht University, Utrecht 3584CM, Netherlands; Institute for Breeding Rare and Endangered Mammals, Edinburgh, United Kingdom; Department of Biomedical Sciences/Biochemistry, University of Veterinary Medicine, Vienna A-1210, Austria; School of Zoology, University of Tasmania, Hobart TAS 7001, Australia; Centre for Wildlife Management, University of Pretoria, Pretoria 0028, South Africa; School of Animal Biology, University of Western Australia, Crawley, WA 6009, Australia
Biologically inert material in feces may confound interpretations of noninvasive fecal endocrine data, because it may induce variance related to differences in foraging behavior rather than to differences in endocrine activity. We evaluated two different enzyme immunoassays (EIAs) for the noninvasive evaluation of adrenocortical activity in ground-feeding aardwolves (Proteles cristata) and tested the influence of soil content in aardwolffeces on the interpretation of fecal glucocorticoid metabolite data. Using adrenocorticotropic hormone (ACTH) challenges for validation, we successfully identified a cortisol EIA suitable for assessing adrenocortical activity in aardwolves. An alternatively tested 11-oxoetiocholanolone EIA failed to detect a biologically relevant signal after ACTH administration. Although the proportion of inorganic content in aardwolf feces did not alter qualitative conclusions from the endocrine data, the data related to mass of organic content had a larger amount of variance attributed to relevant biological contrasts and a lower amount of variance attributed to individual variation, compared with data related to total dry mass of extracted material. Compared with data expressed as dry mass of extracted material, data expressed as mass of organic content may provide a more refined and statistically powerful measure of endocrine activity in species that ingest large amounts of indigestible material. © 2012 by The University of Chicago. All rights reserved.
11 oxoetiocholanolone; 11-ketoetiocholanolone; corticotropin; drug derivative; etiocholanolone; glucocorticoid; hydrocortisone; comparative study; endocrine disruptor; feces; felid; foraging behavior; immunoassay; steroid; adrenal cortex; animal; article; Carnivora; chemistry; diet; enzyme immunoassay; feces; feeding behavior; female; immunology; male; metabolism; methodology; soil; validation study; Adrenal Cortex; Adrenocorticotropic Hormone; Animals; Diet; Etiocholanolone; Feces; Feeding Behavior; Female; Glucocorticoids; Hyaenidae; Hydrocortisone; Immunoenzyme Techniques; Male; Soil; Proteles; Proteles cristatus