Zheng Wei-Hong, Li Ming, Liu Jin-Song, Shao Shu-Li
School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325027, China.
Comp Biochem Physiol A Mol Integr Physiol. 2008 Dec;151(4):519-25. doi: 10.1016/j.cbpa.2008.07.009. Epub 2008 Jul 11.
Acclimatization to winter conditions is an essential prerequisite for survival of small passerines of the northern temperate zone. Changes in photoperiod, ambient temperature and food availability trigger seasonal acclimatization in physiology and behavior of many birds. In the present study, seasonal adjustments in several physiological, hormonal, and biochemical markers were examined in wild-captured Eurasian tree sparrows (Passer montanus) from the Heilongjiang Province in China. In winter sparrows had higher body mass and basal metabolic rate (BMR). Consistently, the dry mass of liver, heart, gizzard, small intestine, large intestine and total digestive tract were higher in winter than in that in summer. The contents of mitochondrial protein in liver, and state-4 respiration and cytochrome c oxidase (COX) activity in liver and muscle increased significantly in winter. Circulating level of serum triiodothyronine (T3) was significantly higher in winter than in summer. Together, these data suggest that tree sparrows mainly coped with cold by enhancing thermogenic capacities through increased organ masses and heightened activity of respiratory enzymes activities. The results support the view that prominent winter increases in BMR are manifestations of winter acclimatization in tree sparrows and that seasonal variation in metabolism in sparrows is similar to that in other small temperate-wintering birds.
适应冬季条件是北半球温带小型雀形目鸟类生存的必要前提。光周期、环境温度和食物可利用性的变化会引发许多鸟类生理和行为上的季节性适应。在本研究中，对从中国黑龙江省野生捕获的欧亚树麻雀（Passer montanus）的几种生理、激素和生化指标的季节性调整进行了检测。冬季麻雀的体重和基础代谢率（BMR）更高。同样，冬季肝脏、心脏、砂囊、小肠、大肠和整个消化道的干重均高于夏季。冬季肝脏线粒体蛋白含量以及肝脏和肌肉中的状态4呼吸和细胞色素c氧化酶（COX）活性显著增加。血清三碘甲状腺原氨酸（T3）的循环水平在冬季显著高于夏季。这些数据共同表明，树麻雀主要通过增加器官质量和提高呼吸酶活性来增强产热能力，从而应对寒冷。结果支持了这样的观点，即冬季BMR的显著增加是树麻雀冬季适应的表现，且麻雀新陈代谢的季节性变化与其他小型温带越冬鸟类相似。
