Santamaria Flavia, Schlagloth Rolf, Palme Rupert, 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 Nov 25;11(12):3376. doi: 10.3390/ani11123376.
Faecal material can be a valuable source of information for a range of animal health aspects and can be used to measure faecal cortisol metabolites (FCMs). FCM values can relate to physiological stress responses. However, freshly defecated pellets are not always available and environmental conditions, such as temperature and humidity, might affect faecal pellet consistency and FCM levels. Therefore, the impact of environmental conditions on FCMs needs to be evaluated. We collected 107 pellets from two female and two male koalas, exposed them to three types of treatments, and analysed FCMs in these samples with three enzyme immunoassays (EIAs). After analysis, the original FCM values were mathematically corrected for water loss. Results show that the FCMs were more stable when measured using tetrahydrocorticosterone (50c) and 5α-pregnane-3β,11β,21-triol-20-one (37e) EIAs, and were less stable when measured with the cortisol EIA. With 50c, the FCM values did not vary significantly over time either before or after the adjustment with water in the environment treatment group. For samples kept under constant low (25 °C) and high (35 °C) temperatures, the 50c FCM values did not vary significantly over time, after adjustments were made for water loss. Thus, this study highlights the importance of considering the suitability of faecal field samples for FCM analysis. Because water loss was the main driver of FCM changes, we strongly recommend collecting koala pellets that are freshly defecated, despite the effort and time it might take to collect such pellets.
粪便材料可以成为一系列动物健康方面有价值的信息来源，并且可用于测量粪便皮质醇代谢物（FCM）。FCM值可能与生理应激反应相关。然而，刚排出的粪便颗粒并非总是可得的，而且环境条件，如温度和湿度，可能会影响粪便颗粒的稠度和FCM水平。因此，需要评估环境条件对FCM的影响。我们从两只雌性和两只雄性考拉身上收集了107颗粪便颗粒，对它们进行了三种处理，并使用三种酶免疫测定法（EIA）分析了这些样本中的FCM。分析后，对原始FCM值进行了水分损失的数学校正。结果表明，使用四氢皮质酮（50c）和5α-孕烷-3β,11β,21-三醇-20-酮（37e）EIA测量时，FCM更稳定，而使用皮质醇EIA测量时则较不稳定。使用50c时，在环境处理组中，无论在水分调整之前还是之后，FCM值随时间均无显著变化。对于在恒定低温（25°C）和高温（35°C）下保存的样本，在对水分损失进行调整后，50c FCM值随时间也无显著变化。因此，本研究强调了考虑粪便现场样本用于FCM分析的适用性的重要性。由于水分损失是FCM变化的主要驱动因素，我们强烈建议收集刚排出的考拉粪便颗粒，尽管收集此类颗粒可能需要付出努力和时间。
