Effect of food restriction on energy budget in warm-acclimated striped hamsters.
The capacity of small mammals to sustain periods of food shortage largely depends on the adaptive regulation of energy budget in response to the decrease in food supply. In addition to food availability, ambient temperature (Ta) is an important factor affecting the rates of both energy intake and expenditure. To examine the effect of Ta on energy strategy and the capacity to sustain food shortage, striped hamsters were exposed to a warm condition (30°C) and were then restricted to 70% of ad libitum food intake. Body mass, energy intake and expenditure and physiological markers indicative of thermogenesis were measured. Warm exposure had no effect on body mass and digestibility, but decreased energy intake, basal metabolic rate and maximum nonshivering thermogenesis. The mitochondria protein content, cytochrome c oxidase activity and uncoupling protein 1 level of brown adipose tissue were significantly lower in hamsters at 30°C than at 21°C. Food restriction induced a significant decrease in body mass, but the decreased body mass was attenuated at 30°C relative to 21°C. This suggests that striped hamsters could not compensate for the limited food supply by decreasing daily energy expenditure at 21°C, whereas they could at 30°C. The significant reductions in the rates of metabolism and thermogenesis in warm-acclimated hamsters increase the capacity to cope with food shortage. Although, it remains uncertain whether this response represents some generalized evolutionary adaptation, the Ta-dependent adjustment in the capacity to survive food restriction may reflect that warm acclimation plays an important role in adaptive regulation of both physiology and behavior in response to the variations of food availability.
School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China; State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China. Electronic address: zhao73@foxmail.com.
Zhi-Jun
ZJ
Zhao
State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China.
Qing-Sheng
QS
Chi
School of Agricultural Science, Liaocheng University, Liaocheng, Shandong 252059, China.
Liang
L
Zhao
School of Agricultural Science, Liaocheng University, Liaocheng, Shandong 252059, China.
Qiao-Xia
QX
Zhu
School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China.
Jing
J
Cao
State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China.
De-Hua
DH
Wang
D000064:Acclimatization / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001823:Body Composition / Q000502:physiology; D006224:Cricetinae / Q000502:physiology*; D004435:Eating / Q000502:physiology; D003576:Electron Transport Complex IV / Q000378:metabolism; D002149:Energy Intake / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005508:Food Deprivation / Q000502:physiology*; D007473:Ion Channels / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D022722:Thermogenesis / Q000502:physiology*; D000071256:Uncoupling Protein 1
D007473:Ion Channels; D024101:Mitochondrial Proteins; D000071256:Uncoupling Protein 1; D003576:Electron Transport Complex IV
Basal metabolic rate; Energy budget; Food shortage; Striped hamster; Thermogenesis