Department of Biology, University of Saskatchewan, Canada.
Department of Veterinary Biomedical Sciences, University of Saskatchewan, Canada.
Gen Comp Endocrinol. 2019 May 1;275:15-24. doi: 10.1016/j.ygcen.2019.02.003. Epub 2019 Feb 5.
Non-invasive measures of glucocorticoid (GC) hormones and their metabolites, particularly in feces and hair, are gaining popularity as wildlife management tools, but species-specific validations of these tools remain rare. We report the results of a validation on black-tailed prairie dogs (Cynomys ludovicianus), a highly social engineer of the grasslands ecosystem that has experienced recent population declines. We captured adult female prairie dogs and brought them into temporary captivity to conduct an adrenocorticotropic hormone (ACTH) stimulation test, assessing the relationship between plasma GC and fecal glucocorticoid metabolite (FGM) levels following a single injection of a low (4 IU/kg) or high dose (12 IU/kg) of ACTH, compared to a single injection of saline. We also gave repeated injections of ACTH to adult females to assess whether this would result in an increase of hair cortisol concentrations, compared with control individuals repeatedly injected with saline. A single injection of ACTH at either low or high dose peaked plasma cortisol levels after 30 min, and thereafter the cortisol levels declined until 120 min, where they returned to pre-treatment levels comparable to those of the saline injected group. Despite the significant elevation of plasma cortisol in the treatment groups following ACTH injection, the elevation of FGM levels in the treatment groups were not significantly different from those in the control group over the following 12 h. Repeated injection of a high dose of ACTH failed to increase hair cortisol concentration in treatment animals. Instead, hair cortisol levels remained comparable to the pre-treatment mean, despite an increase in post-treatment hair cortisol levels seen in the saline-injected group. The magnitude of increase in the saline control group was comparable to natural seasonal variation seen in unmanipulated individuals. These results highlight that while measurement of GCs and their metabolites in feces and hair are potentially valuable conservation tools for black-tailed prairie dogs, further validation work is required before these matrices can be to real-world conservation applications.
非侵入性的糖皮质激素 (GC) 激素及其代谢物的测量方法，特别是在粪便和毛发中，作为野生动物管理工具越来越受欢迎，但这些工具的物种特异性验证仍然很少。我们报告了对黑尾草原犬鼠（Cynomys ludovicianus）的验证结果，这是一种高度社会化的草原生态系统工程师，其数量近年来有所下降。我们捕获了成年雌性草原犬鼠，并将它们带入临时圈养地进行促肾上腺皮质激素 (ACTH) 刺激试验，评估了单次注射低剂量 (4IU/kg) 或高剂量 (12IU/kg) ACTH 后，与单次注射生理盐水相比，血浆 GC 与粪便糖皮质激素代谢物 (FGM) 水平之间的关系。我们还对成年雌性草原犬鼠进行了重复注射 ACTH，以评估与反复注射生理盐水的对照个体相比，这是否会导致毛发皮质醇浓度增加。单次注射低剂量或高剂量的 ACTH 后，皮质醇水平在 30 分钟后达到峰值，此后皮质醇水平下降，直到 120 分钟，恢复到与生理盐水注射组相当的治疗前水平。尽管 ACTH 注射后治疗组血浆皮质醇水平显著升高，但在随后的 12 小时内，治疗组 FGM 水平的升高与对照组相比没有显著差异。重复注射高剂量 ACTH 未能增加治疗动物的毛发皮质醇浓度。相反，尽管在生理盐水注射组中看到治疗后毛发皮质醇水平增加，但毛发皮质醇水平仍与治疗前平均值相当。生理盐水对照组的增加幅度与未经处理个体中自然季节性变化相当。这些结果表明，虽然粪便和毛发中 GC 及其代谢物的测量可能是黑尾草原犬鼠的有价值的保护工具，但在这些矩阵可用于实际保护应用之前，还需要进一步的验证工作。
