Effect of stress on fecal glucocorticoid and androgen profiles and antler status in marsh deer (Blastocerus dichotomus)

• Grant number: 22/06320-6
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2023
• End date: February 29, 2024
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: José Maurício Barbanti Duarte
• Grantee: Laís Jaqueline de Souza
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

The influence of cortisol on reproductive hormones and the antler cycle in deer is poorly understood, especially in species that inhabit the tropics. Males from temperate climates have marked breeding seasons, which correlate with the antler cycle due to the photoperiod regency over testosterone secretion. On the other hand, most Neotropical species do not have a well-defined reproductive season, nor a clear association between the antler stage and reproductive status, as marsh deer (Blastocerus dichotomus) for instance. In addition, conflicting data on the influence of cortisol on androgen levels and antler growth demonstrate the need for further studies. In this context, the present project aims to evaluate the correlation between the profiles of fecal glucocorticoids and androgens in captive marsh deer and their influence on the antlers. For this purpose, 17 males of the species will be utilized, which undergo a period of quarantine after transfer between breeding sites, based on the premise that at this stage they will be under a strong effect of stress and high glucocorticoids levels. Daily fecal collections will be carried out during the first 41 days of quarantine, and twice a week until the shedding of the velvet antler coverage of each animal. The antler status will be evaluated weekly during this period. Fecal androgen and glucocorticoid metabolites will be quantified via EIA. At the end, a correlation test will be performed between the parameters, including the age of the males, and the results will be compared between individuals by ANOVA. Thus, we hope to understand the effect of stress on fecal glucocorticoid and androgen levels and, consequently, on antler status.