Effects Of Warm-Acclimation On Energy Metabolism And Thermogenesis In Chinese Bulbuls

In nature, animals are affected by many ecological factors; the important factor is the impact of seasonal variation that is mainly reflected changes in temperature and photoperiod, and the ambient temperature sometimes change dramatically. Therefore, in order to study the stress responses and adaptive thermogenesis of small birds when the temperature increases, we examined the effects on energy metabolism, energy budget, the organ morphology plasticity, the thermal ability of muscle and liver and the expression of avian uncoupling protein (avUCP) mRNA in Chinese bulbul (Pycnonotus sinensis). Fifty adult Chinese bulbuls were live-trapped by mist net in Wenzhou Zhejiang Province in March2013. After one week adaption to laboratory conditions, they were randomly assigned into control group and experimental group, the former’s temperature was10℃and the other was30℃, at the same time, the experimental group was divided into four small group according to different acclimazation time, were1D,3D,7D and28D,respectively. The results showed:with the extension of time to the warm temperature, the body mass (Mb) decreased significantly between the two groups; the overall basal metabolic rate (BMR), the mass-specific BMR, gross energy intake (GEI), gross excretion energy (GEE) and digestible energy intake (DEI) all decreased significantly between groups, there were a minimum value in the first28days, but digestibility markedly increased, and it had the maximum value in the last day; the organ masses declined, wherein the masses of muscle, heart, liver and kidney had significant differences, the digestive tract occurred phenotypic plasticity and its mass and length decreased markedly; moreover, the warm temperature induced interactively in lower state-4-resoiration and the activity of COX in birds, but the content of protein had no significant difference; in addition, the expression of avUCP decreased than control. Our results suggested:the temperature variation affected on each level of energy metabolism of Chinese bulbul, the warm acclimazation induced the stress responses in a short time, the motivation is increasing heat production in response to the suddenly change of ambient temperature and maintaining normal physiological function, after a long time of acclimazation, Chinese bulbul adapted to environment changes and produced adaptive change by adjustment of all physiological functions. So, the regulation of energy metabolism has important meaning in whether physiological or ecological adaption to Chinese bulbul, even small birds. It can be seen phenotypic plasticity is the basic characteristics of energy metabolism for birds.