Validation of an enzyme immunoassay and comparison of fecal cortisol metabolite levels in black and gold howler monkeys (Alouatta caraya) inhabiting fragmented and continuous areas of the humid Chaco region, Argentina

In the last years, the study of how environmental stimuli influence the physiology and specifically the endocrinology of an organism became increasingly important, relying mainly on the quantification of glucocorticoids to monitor animal welfare. Most studies investigating cortisol levels in primates were focused on the impact of social stressors; however, a major concern for the conservation of howler monkeys is the increased habitat fragmentation led by the advancement of the agricultural frontier. We compared fecal cortisol metabolite levels (FGCM) in howler monkeys (Alouatta caraya) living in fragmented and continuous forests of the Argentine humid Chaco region, throughout the warm season (spring‐summer). Fecal samples (n = 114) were collected from adult individuals, and steroid extracts analyzed with an enzyme immunoassay also validated in this work. Parallel displacement curves were obtained between dilutions of pooled fecal extracts and the cortisol standard curve (r2 = 0.99; P = 0.23). Efficiency of the fecal extraction procedure was 79.4% ± 38%; recovery of exogenous hormone added to fecal extracts indicated a low interference of components in the feces with antibody binding. The exogenous administration of ACTH in captive‐bred animals demonstrated a “cause‐and‐effect” relationship between the adrenal gland activation and increased FGCM levels. Contrary to our initial prediction, we were not able to demonstrate a significant difference in...
Source: American Journal of Primatology - Category: Psychiatry & Psychology Authors: Tags: RESEARCH ARTICLE Source Type: research