Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
J Exp Biol. 2010 Jan 1;213(1):45-51. doi: 10.1242/jeb.034488.
Early developmental experiences, such as incubation conditions, can have important consequences for post-hatching fitness in birds. Although the effects of incubation temperature on phenotype of avian hatchlings are poorly understood, recent research suggests that subtle changes in incubation conditions can influence hatchling characteristics, including body size and condition. We designed an experiment to explore the effects of incubation temperature on hatching success, survival to 9 days post hatch, growth and the hypothalamo-pituitary-adrenal (HPA) axis in wood ducks (Aix sponsa). Wood duck eggs were collected from nest boxes and experimentally incubated at three temperatures (35.0, 35.9 and 37.0 degrees C), each falling within the range of temperatures of naturally incubated wood duck nests. Survival and growth were monitored in ducklings fed ad libitum for 9 days post hatch. In addition, baseline and stress-induced plasma corticosterone concentrations were measured in 2 and 9 day old ducklings. Hatching success and survival to 9 days was greatest in ducks incubated at the intermediate temperature. Ducklings incubated at 35.9 degrees C and 37.0 degrees C had 43% higher growth rates than ducklings incubated at 35.0 degrees C. In addition, ducklings incubated at 35.0 degrees C had higher baseline (17-50%) and stress-induced (32-84%) corticosterone concentrations than ducklings incubated at 35.9 degrees C and 37.0 degrees C at 2 and 9 days post hatch. We also found a significant negative correlation between body size and plasma corticosterone concentrations (baseline and stress-induced) in 9 day old ducklings. To our knowledge, this is the first study to demonstrate that thermal conditions experienced during embryonic development can influence the HPA axis of young birds. Our results illustrate that subtle changes (<1.0 degrees C) in the incubation environment can have important consequences for physiological traits important to fitness.
早期的发育经历，如孵化条件，可能对鸟类孵化后的适应能力产生重要影响。尽管孵化温度对雏鸟表型的影响尚不清楚，但最近的研究表明，孵化条件的细微变化会影响雏鸟的特征，包括体型和健康状况。我们设计了一个实验，以探索孵化温度对孵化成功率、孵化后 9 天的存活率、生长和下丘脑-垂体-肾上腺（HPA）轴的影响在木鸭（Aix sponsa）中。木鸭卵从巢箱中收集，并在三个温度（35.0、35.9 和 37.0 摄氏度）下进行实验孵化，每个温度都在自然孵化的木鸭巢温度范围内。在孵化后 9 天自由喂食的雏鸭中监测存活率和生长情况。此外，还测量了 2 天和 9 天龄雏鸭的基础和应激诱导的血浆皮质酮浓度。在中间温度下孵化的鸭子孵化成功率和孵化后 9 天的存活率最高。在 35.9 和 37.0 摄氏度下孵化的雏鸭比在 35.0 摄氏度下孵化的雏鸭生长速度快 43%。此外，在孵化后 2 天和 9 天，在 35.0 摄氏度下孵化的雏鸭的基础（17-50%）和应激诱导（32-84%）皮质酮浓度比在 35.9 和 37.0 摄氏度下孵化的雏鸭高。我们还发现，9 天龄雏鸭的体型与血浆皮质酮浓度（基础和应激诱导）之间存在显著负相关。据我们所知，这是第一个证明胚胎发育过程中经历的热条件会影响幼鸟 HPA 轴的研究。我们的结果表明，孵化环境的细微变化（<1.0°C）对与适应能力相关的生理特征有重要影响。
