Influence of husbandry systems on physiological stress reactions of captive brown brocket (Mazama gouazoubira) and marsh deer (Blastocerus dichotomus)-noninvasive analysis of fecal cortisol metabolites

Abstract

This longitudinal study addresses the relationship of different husbandry systems to fecal cortisol metabolites (FCM) concentrations in captive brown brocket deer and marsh deer in order to ascertain a less stressful captive condition for these species. Thus, three pairs from both species were submitted to three different husbandry systems (10 days per system), and fecal samples were collected in the last 5 days of each management. A cortisol enzyme immunoassay was validated and used to measure FCM. The physiological significance of these measurements was verified in brown brocket deer by an adrenocorticotropic hormone challenge test, which induced a fourfold (above baseline) increase of FCM within 24 to 28 h. In marsh deer, wild-capture individuals (2,802 +/- 115 ng/g) had significantly higher concentrations (P < 0.05) than captive-born ones (122 +/- 32 ng/g). Higher values of FCM (P < 0.05) were measured in brown brocket deer kept as pairs in outdoor exhibits all day (150 +/- 15 ng/g) compared to animals kept integrally in individual stalls (71 +/- 7 ng/g) or in outdoor exhibits during daytime and individual stalls during nighttime (78 +/- 4 ng/g). In contrast, no differences in FCM were found in marsh deer submitted to any husbandry system (P > 0.05). These findings suggest that brown brocket deer may benefit from husbandry systems, which keep animals at least for one period in individual stalls, while marsh deer apparently exhibit a high individual variability to different husbandry conditions with no generic pattern to its better maintenance in captivity.