Instituto de Ciencia y Tecnología de los Alimentos and Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba (UNC), Argentina; Instituto de Diversidad y Ecología Animal (IDEA), FCEFyN, UNC and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
Instituto de Ciencia y Tecnología de los Alimentos and Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba (UNC), Argentina; Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), FCEFyN, UNC and CONICET, Argentina.
Gen Comp Endocrinol. 2019 Sep 1;280:91-96. doi: 10.1016/j.ygcen.2019.04.015. Epub 2019 Apr 16.
Faecal glucocorticoid measurement is a potentially important tool for improving wildlife conservation, but its use is still limited by methodological issues including the need to avoid modifications of steroids by faecal microorganisms during storage. The freezing of faeces is recommended as a means of avoiding such alterations, but this is costly under non-controlled environmental conditions. The present study was designed to determine whether the application of thymol reduced the proliferation of microorganisms in the faeces of Tamandua tetradactyla and whether it influenced faecal glucocorticoid metabolite (FGM) measurements. Tamandua tetradactyla faeces were individually collected after defaecation, divided into fractions (5.5 g each) and kept in sealed glass Petri dishes at 22 ± 2 °C. A thymol solution (550 µL; 5 mg g feces; 80% ethanol) or an 80% ethanol solution (550 µL, control) was added before storage of faeces. Negative controls for FGM consisted of samples without thymol or ethanol solutions. All samples were evaluated at 0, 24, 48 and 72 h post-defaecation. Thymol was first incubated with a glucocorticoid standard in a faeces-free tube or in a faecal sample in order to determine whether it interfered with FGM measurements. Data showed that thymol did not affect FGM measurements. Post-defaecation time caused a significant reduction in FGM measurements in the negative control, an increment at 48 h in the control, and no change in FGM measurements in thymol treatment. FGM measurements were significantly different between groups (negative control > control - treatment). Thymol caused a significant reduction of up to three orders of magnitude in total coliforms, total aerobic and anaerobic heterotrophic mesophilic bacteria, mold and yeast per gram of faeces at 24, 48 and 72 h. The reduction in microbial activity presumably contributed to the stability of FGM over time. Spore-forming bacteria (SFB) in faeces were not reduced by thymol. We propose thymol as an alternative to freezing since it stabilizes FGMs for at least 3 days after collection in the faeces of Tamandua tetradactyla.
粪便糖皮质激素测量是提高野生动物保护的一种潜在重要工具，但它的使用仍然受到方法学问题的限制，包括需要避免粪便微生物在储存过程中对类固醇的修饰。冷冻粪便被推荐作为避免这种改变的一种方法，但在非控制环境条件下，这是昂贵的。本研究旨在确定百里香是否能减少三趾树懒粪便中微生物的增殖，以及它是否影响粪便糖皮质激素代谢物（FGM）的测量。三趾树懒粪便在排便后单独收集，分成（5.5 克）等分，并在密封的玻璃培养皿中于 22±2°C 保存。在储存粪便之前，加入百里香溶液（550µL；5mg•g粪便；80%乙醇）或 80%乙醇溶液（550µL，对照）。FGM 的阴性对照由不含百里香或乙醇溶液的样品组成。所有样品在排便后 0、24、48 和 72 小时进行评估。百里香首先在无粪便管或粪便样品中与糖皮质激素标准孵育，以确定它是否干扰 FGM 测量。数据显示，百里香不影响 FGM 测量。粪便后时间对阴性对照中的 FGM 测量有显著降低，对照中在 48 小时有增加，而在百里香处理中 FGM 测量没有变化。FGM 测量在各组之间有显著差异（阴性对照>对照-处理）。百里香在 24、48 和 72 小时时，使粪便中总大肠菌群、总需氧和厌氧异养嗜温细菌、霉菌和酵母的数量每克减少了三个数量级。微生物活性的减少可能有助于 FGM 随时间的稳定性。粪便中的孢子形成细菌（SFB）未被百里香减少。我们提出百里香作为冷冻的替代品，因为它可以在三趾树懒粪便中收集后至少 3 天稳定 FGM。
