Patterns of faecal glucocorticoid metabolite levels in captive roan antelope (Hippotragus equinus) in relation to reproductive status and season

Populations
of roan antelope (Hippotragus equinus)
in southern Africa have experienced a drastic decline over the past few decades
and this situation has led to the development of intensive breeding programmes
to support conservation efforts. However, little is known about related welfare
aspects including stress-related physiological biomarkers. The present study
set out to establish a non-invasive method to monitor faecal glucocorticoid
metabolite (fGCM) concentrations as a measure of stress and determine fGCM concentrations
in relation to male reproductive activity and female reproductive status in the
roan antelope. An adrenocorticotrophic hormone challenge was performed using two
adult roan antelope (one male and one female) at Lapalala Wilderness Nature
Reserve, South Africa, to determine the suitability of five enzyme immunoassays
(EIA) for monitoring adrenocortical function in H. equinus. An 11-oxoaetiocholanolone
I EIA detecting 11,17 dioxoandrostanes performed best showing 17-20 folds
increases in fGCM concentrations after 12h-17h post-injection. The identified
EIA was then used to monitor fGCM concentrations during active and non-active reproductive
periods in males (n=3), and during periods of lactation, mating, gestation, and
postpartum in females (n=18). Males showed an overall 80% increase in fGCM
concentrations when reproductively active and females showed a progressively significant
increase in fGCM levels throughout pregnancy, with overall fGCM concentrations being
1.5- and 2.6-fold higher than the respective fGCM concentrations during periods
of lactation and mating. Furthermore, fGCM concentrations remained above baseline
for up to 21 days post-partum. A correlation between ecological parameters
(rainfall and temperature) and fGCM concentrations revealed elevated fGCM
concentrations during the dry season for males and females. The non-invasive
method validated in this study provides a valuable tool to quantify
stress-related biomarkers in roan antelope, and findings can be used to support
management decisions in conservation breeding facilities.

南部非洲罗氏羚羊（Hippotragus equinus）的种群数量在过去的几十年中经历了急剧下降，此状况促使人们开展了一系列密集的繁殖计划以支持保护工作。然而，关于相关福利方面的知识甚少，包括与压力相关的生理生物标志物。本研究旨在建立一种非侵入性方法，用以监测粪便中糖皮质激素代谢物（fGCM）的浓度，并将其作为压力的衡量指标，同时确定fGCM浓度与罗氏羚羊的雄性生殖活动和雌性生殖状态之间的关系。在南非的Lapalala荒野自然保护区，通过使用两只成年罗氏羚羊（一雄一雌）进行了促肾上腺皮质激素挑战实验，以确定五种酶联免疫吸附测定（EIA）在监测H. equinus肾上腺皮质功能方面的适用性。一种检测11,17-二氧雄甾烷的11-氧雌酮醇I EIA表现出最佳性能，注射后12至17小时fGCM浓度增加了17至20倍。随后，所识别的EIA被用于监测雄性（n=3）在活跃和非活跃生殖期以及雌性（n=18）在哺乳、交配、妊娠和产后期间的fGCM浓度。雄性在生殖活跃时fGCM浓度总体上升了80%，而雌性在整个妊娠期间fGCM水平呈渐进性显著增加，总体fGCM浓度分别为哺乳和交配期间fGCM浓度的1.5倍和2.6倍。此外，产后fGCM浓度维持在基线以上长达21天。生态参数（降雨量和温度）与fGCM浓度的相关性揭示了在干旱季节雄性和雌性的fGCM浓度升高。本研究验证的非侵入性方法为量化罗氏羚羊的压力相关生物标志物提供了一个宝贵的工具，其研究结果可用于支持保护繁殖设施的管理决策。