Butler Michael W, Leppert Lynda L, Dufty Alfred M
Department of Biological Sciences, Boise State University, Boise, Idaho 83725, USA.
Physiol Biochem Zool. 2010 Jan-Feb;83(1):78-86. doi: 10.1086/648483.
Stressors encountered during avian development may affect an individual's phenotype, including immunocompetence, growth, and feather quality. We examined effects of simulated chronic low-level stress on American kestrel (Falco sparverius) nestlings. Continuous release of corticosterone, a hormone involved in the stress response, can model chronic stress in birds. We implanted 13-d-old males with either corticosterone-filled implants or shams and measured their growth, immune function, and feather coloration. We found no significant differences between groups at the end of the weeklong exposure period in morphometrics (mass, tarsus, wing length, and asymmetry), immunocompetence (cutaneous immunity, heterophil/lymphocyte ratio, and humoral immunity), or feather coloration. One week subsequent to implant removal, however, differences were detected. Sham-implanted birds had significantly longer wings and a reduced level of cutaneous immune function compared with those of birds given corticosterone-filled implants. Therefore, increases of only 2 ng/mL in basal corticosterone titer can have small but measurable effects on subsequent avian development.
鸟类发育过程中遇到的应激源可能会影响个体的表型，包括免疫能力、生长和羽毛质量。我们研究了模拟慢性低水平应激对美洲红隼雏鸟的影响。皮质酮（一种参与应激反应的激素）的持续释放可以模拟鸟类的慢性应激。我们给13日龄的雄性美洲红隼植入了填充皮质酮的植入物或假植入物，并测量了它们的生长、免疫功能和羽毛颜色。在为期一周的暴露期结束时，我们发现两组在形态学指标（体重、跗跖、翅长和不对称性）、免疫能力（皮肤免疫、嗜异性粒细胞/淋巴细胞比率和体液免疫）或羽毛颜色方面没有显著差异。然而，在取出植入物一周后，检测到了差异。与植入填充皮质酮植入物的鸟类相比，假植入鸟类的翅膀明显更长，皮肤免疫功能水平降低。因此，基础皮质酮滴度仅增加2 ng/mL就可能对随后的鸟类发育产生微小但可测量的影响。
