Thermal Physiology and Bioenergetics in Ambient or Seasonal Acclimatization in Apodemus chevrieri

Physiological adjustments to seasonal variations of the environment, such as changes in body mass and energy metabolism, are important adaptive strategies for small mammals. Ambient cues, as temperature and photoperiod, play important roles in animals' physiological adjustments. In order to determine the contributions of temperature and photoperiod to seasonal changes in body mass and thermogenesis in Apodemus chevrieri, we examined seasonal-acclimatized and lab-acclimated animals on several physiological, hormonal, and biochemical markers indicative of thermogenic capacity. The results showed that A. chevrieri adapt to winter or under cold condition by increasing thermogenesis and food intake. The present results suggest that the observed physiological regulation from the organismal, hormonal levels to the cellular levels of this alpine small mammal were important and allowed A cheerier: to overcome the physiological challenges of an change to cold environment in winter successfully with the seasonal variations. Cold can induce an increase in mitochondrial protein contents and COX activity both in liver and brown adipose tissue, suggesting that A. chevrieri was more sensitive to cold than that of photoperiod. Together, these data suggested that A. chevrieri mainly depend on increasing thermogenic capacity to cope with cold or winter condition.