Lattin Christine R, Pechenenko Anita V, Carson Richard E
Department of Radiology and Biomedical Imaging, Yale University, 801 Howard Avenue, PO Box 208048, New Haven, CT 06520-8048, United States.
Department of Radiology and Biomedical Imaging, Yale University, 801 Howard Avenue, PO Box 208048, New Haven, CT 06520-8048, United States.
Horm Behav. 2017 Mar;89:121-129. doi: 10.1016/j.yhbeh.2016.12.016. Epub 2017 Jan 5.
Wild animals and captives display physiological and behavioral differences, and it has been hypothesized, but rarely tested, that these differences are caused by sustained elevation of the hormone corticosterone. We used repeated computed tomography (CT) imaging to examine body composition changes in breeding male and female wild house sparrows (Passer domesticus; n=20) in response to two weeks of captivity, and assessed behavioral changes using video recordings. Half of the birds received the drug mitotane, which significantly decreased stress-induced corticosterone titers compared to controls. Based on the CT images, fat volumes increased, and pectoralis muscle density and heart and testes volumes decreased, over the two weeks of captivity in both groups of birds. However, beak-wiping, a behavior that can indicate anxiety and aggression, showed increased occurrence in controls compared to mitotane-treated birds. While our results do not support the hypothesis that these body composition changes were primarily driven by stress-induced corticosterone, our data suggest that experimentally reducing stress-induced corticosterone may mitigate some captivity-induced behavioral changes. Broadly, our results emphasize that researchers should take behavioral and physiological differences between free-living animals and captives into consideration when designing studies and interpreting results. Further, time in captivity should be minimized when birds will be reintroduced back to the wild.
野生动物和圈养动物表现出生理和行为上的差异，有人曾提出假说（但很少进行验证），认为这些差异是由激素皮质酮的持续升高所致。我们使用重复计算机断层扫描（CT）成像来检查野生家麻雀（Passer domesticus；n = 20）繁殖期雌雄个体在两周圈养期间的身体成分变化，并通过视频记录评估行为变化。一半的鸟类接受了米托坦药物治疗，与对照组相比，该药物显著降低了应激诱导的皮质酮水平。根据CT图像，两组鸟类在两周的圈养期间，脂肪体积增加，胸肌密度以及心脏和睾丸体积减小。然而，与接受米托坦治疗的鸟类相比，对照组中表现出焦虑和攻击性的“擦喙”行为出现频率增加。虽然我们的结果不支持这些身体成分变化主要由应激诱导的皮质酮驱动这一假说，但我们的数据表明，通过实验降低应激诱导的皮质酮可能会减轻一些圈养引起的行为变化。总体而言，我们的结果强调，研究人员在设计研究和解释结果时应考虑自由生活动物和圈养动物之间的行为和生理差异。此外，当鸟类将被重新放归野外时，应尽量缩短圈养时间。
