Wildlife Institute of India, Chandrabani, Dehradun, Uttarakhand 248001 India.
Wildlife Institute of India, Chandrabani, Dehradun, Uttarakhand 248001 India.
Gen Comp Endocrinol. 2021 Sep 1;310:113833. doi: 10.1016/j.ygcen.2021.113833. Epub 2021 Jun 4.
Faecal glucocorticoid (GC) and triiodothyronine (T3) metabolites and their interactions are increasingly used to monitor perceived stress and nutritional challenges in free-ranging animals. However, a number of extrinsic and intrinsic factors including hormone-inert dietary materials, inorganic matters etc. are known to affect reliable hormone metabolite quantifications. In this study, the impacts of inorganic matter (IOM) on faecal GC (fGCMs) and T3 (fT3Ms) metabolite measure were addressed in wild tiger (n = 193 from Terai Arc landscape, India) and captive lion (n = 120 from Sakkarbaug Zoological Garden, Gujarat, India) and possible corrective measures were evaluated. The wild tiger samples contained highly variable IOM content (9-98%, mostly with > 40% IOM) compared to captive Asiatic lion (17-57%, majority with < 40% IOM). Significant correlations were observed between IOM content and tiger fGCM (r = -0.46, p = 0.000), fT3M (r = -0.58, p = 0.000) and lion fT3M measures (r = -0.43, p = 0.003). Two corrective measures viz. removing samples with ≥ 80% IOM and subsequently expressing concentrations as per gram of organic dry matter (instead of total dry matter) reduced IOM influence on tiger fGCM, fT3M and lion fT3M, without affecting lion fGCM measures. The corrective measures changed the interpretations of fT3M data of field-collected tiger samples with no significant changes in fGCM (both tiger and lion) and fT3M (lion) data. As faecal IOM content is common in many wild species, the results emphasize the need to reduce IOM-driven hormone data variation for ecologically relevant interpretations towards species conservation.
粪便中的糖皮质激素（GC）和三碘甲状腺原氨酸（T3）代谢物及其相互作用越来越多地被用于监测野生动物的感知压力和营养挑战。然而，已知许多外在和内在因素，包括激素惰性膳食物质、无机物等，会影响可靠的激素代谢物定量。在这项研究中，我们研究了无机物（IOM）对野生虎（来自印度特莱弧形景观，n=193）和圈养狮子（来自印度古吉拉特邦萨卡尔巴格动物园，n=120）粪便 GC（fGCMs）和 T3（fT3Ms）代谢物测量的影响，并评估了可能的纠正措施。与圈养亚洲狮（IOM 含量 17-57%，大部分<40% IOM）相比，野生虎的样本中含有高度可变的 IOM 含量（9-98%，大部分>40% IOM）。观察到 IOM 含量与虎 fGCM（r=-0.46，p=0.000）、fT3M（r=-0.58，p=0.000）和狮子 fT3M 测量值（r=-0.43，p=0.003）之间存在显著相关性。两种纠正措施，即去除 IOM 含量≥80%的样本，然后根据有机干物质（而不是总干物质）表达浓度，减少了 IOM 对虎 fGCM、fT3M 和狮子 fT3M 的影响，而不影响狮子 fGCM 测量值。这些纠正措施改变了野外收集的虎样本中 fT3M 数据的解释，而 fGCM（虎和狮）和 fT3M（狮）数据没有显著变化。由于粪便中的 IOM 含量在许多野生动物中很常见，因此研究结果强调了需要减少激素数据的变化，以便对物种保护进行生态相关的解释。
