Santamaria Flavia, Palme Rupert, Schlagloth Rolf, Klobetz-Rassam Edith, Henning Joerg
Koala Research-Central Queensland and Flora, Fauna and Freshwater Research, School of Health, Medical and Applied Sciences, Central Queensland University, North Rockhampton, QLD 4702, Australia.
Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria.
Animals (Basel). 2021 May 31;11(6):1622. doi: 10.3390/ani11061622.
The Koala () is an endemic marsupial inhabiting four states of Australia. Urbanisation, declining habitat, drought and fires are threatening the survival of this flagship species. These threats may cause acute and chronic stress in koalas, which might also be associated with occurrence of infectious diseases in koala populations. Stress may induce an increase in cortisol reflected in increased faecal cortisol metabolite (FCM) values. To be able to use faecal cortisol metabolites to measure stress levels in this species, our aim was to determine baseline values for males and females during breeding and non-breeding season. A total of 351 defecations were collected fortnightly, twice a day, for 12 months from koalas at a wildlife facility in South East Queensland. Samples were analysed with three different enzyme immunoassays (EIAs): a cortisol, 5α-pregnane-3β,11β,21-triol-20-one (37e) and tetrahydrocorticosterone (50c) EIA. The latter, which also reacts with tetrahydrocortisol, the main metabolite in koala faeces, was found to have the highest biological sensitivity and, therefore, is the most suitable EIA to measure stress levels in koalas. Utilising this EIA, we found significant differences ( < 0.05) in FCM values between males and females, breeding and non-breeding season, and between morning and evening samples. Values of faecal cortisol metabolites established in stress-free koalas in this study can serve as a reference for future studies in koalas.
考拉（）是一种澳大利亚特有的有袋动物，栖息于澳大利亚的四个州。城市化、栖息地减少、干旱和火灾正威胁着这种旗舰物种的生存。这些威胁可能会给考拉带来急性和慢性应激，这也可能与考拉种群中传染病的发生有关。应激可能会导致皮质醇增加，粪便皮质醇代谢物（FCM）值升高就反映了这一点。为了能够利用粪便皮质醇代谢物来测量该物种的应激水平，我们的目标是确定雄性和雌性在繁殖季节和非繁殖季节的基线值。在昆士兰州东南部的一个野生动物设施中，对考拉进行了为期12个月的采样，每周两次，每天两次，共收集了351份粪便。样本用三种不同的酶免疫测定法（EIA）进行分析：皮质醇、5α-孕烷-3β,11β,21-三醇-20-酮（37e）和四氢皮质酮（50c）EIA。发现后者还与考拉粪便中的主要代谢物四氢皮质醇发生反应，具有最高的生物敏感性，因此是测量考拉应激水平最合适的EIA。利用这种EIA，我们发现雄性和雌性、繁殖季节和非繁殖季节以及早晨和晚上的样本之间FCM值存在显著差异（<0.05）。本研究中在无应激考拉中确定的粪便皮质醇代谢物值可为未来考拉研究提供参考。
