Spencer K A, Verhulst S
School of Biological Sciences, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.
Horm Behav. 2007 Feb;51(2):273-80. doi: 10.1016/j.yhbeh.2006.11.001. Epub 2006 Dec 28.
Early developmental conditions can significantly influence the growth and survival of many animal species. We studied the consequences of exposure to corticosterone (CORT), a stress hormone, during the nestling stage on two behavioral traits (neophobia, social dominance) measured when the birds had reached independence. Nestling zebra finches (Taeniopygia guttata) were exposed twice daily to exogenous CORT via oral administration for a 12-day period up until fledging. Experimental CORT administration depressed nestling growth rates, confirming results previously obtained in this species. Our data on neophobic behavior revealed a significant interaction between sex and treatment, with CORT-dosed males showing reduced latencies to approach a novel object, while there was little effect of corticosterone treatment on female neophobia. There was no significant effect of age (30 or 50 days), however, there was a non-significant trend towards an interaction between treatment and age, with neophobia increasing with age in the CORT-dosed birds, but decreasing in controls. At 50 days of age previous exposure to corticosterone resulted in reduced success in competitions for a non-food-based resource (a perch) in both sexes. There were no effects of brood size on any behavioral traits measured here, but this may be due to the small range in brood size used. Our results show that elevated levels of stress hormones during postnatal development can have significant effects on important behavioral traits, i.e., neophobia and dominance. Moreover, they confirm the importance of rearing conditions in shaping adult phenotypes.
早期发育条件会显著影响许多动物物种的生长和存活。我们研究了雏鸟阶段接触应激激素皮质酮（CORT）对鸟类独立后所测量的两种行为特征（新物恐惧、社会优势）的影响。斑胸草雀雏鸟在离巢前的12天里，每天通过口服接受两次外源性CORT。实验性给予CORT会降低雏鸟的生长速度，这证实了此前在该物种中获得的结果。我们关于新物恐惧行为的数据显示，性别和处理之间存在显著交互作用，接受CORT处理的雄性接近新物体的潜伏期缩短，而皮质酮处理对雌性新物恐惧几乎没有影响。年龄（30天或50天）没有显著影响，然而，处理和年龄之间存在不显著的交互作用趋势，接受CORT处理的鸟类新物恐惧随年龄增加，而对照组则减少。在50日龄时，之前接触皮质酮导致两性在争夺非食物资源（栖木）的竞争中成功率降低。窝雏数对这里测量的任何行为特征都没有影响，但这可能是由于所使用的窝雏数范围较小。我们的结果表明，出生后发育过程中应激激素水平升高会对重要行为特征，即新物恐惧和优势产生显著影响。此外，它们证实了饲养条件在塑造成年表型中的重要性。
