Energy metabolism, thermogenesis and body mass regulation in tree shrew (Tupaia belangeri) during subsequent cold and warm acclimation

AbstractThis study investigates the energy strategies of a small mammal in response to food shortages as a function of food restriction (FR), metabolic rate and ambient temperature. We subjected tree shrews (Tupaia belangeri) to FR and measured body mass, survival rate, resting metabolic rate (RMR), nonshivering thermogenesis (NST) and cytochrome c oxidase (COX) activity of brown adipose tissue (BAT). Cold-exposed animals restricted to 80% of ad libitum food intake had significantly increased RMR and NST and decreased body mass and survival rates compared with those kept at room temperature on the same FR level. Animals classified has having a high RMR consumed 30.69% more food than those classified as having a low RMR, but showed no differences in body mass or survival when restricted to 80% of ad libitum food intake. These results indicate that tree shrews, known for their relatively high metabolic rates, are sensitive to periods of FR, which supports the metabolic switch hypothesis. Our findings are also consistent with the prediction that small mammals with food hoarding behaviors, like tree shrews, may have a lower tolerance for food shortages than non-hoarding species.

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Effects of fasting and re-feeding on energy metabolism and thermogenesis in the tree shrew (Tupaia belangeri)

Animal Biology ◽

10.1163/15707563-00002427 ◽

2014 ◽

Vol 64 (1) ◽

pp. 31-47 ◽

Cited By ~ 6

Author(s):

Wen-rong Gao ◽

Wan-long Zhu ◽

Di Zhang ◽

Shu-ran Sun ◽

Zheng-kun Wang

Keyword(s):

Adipose Tissue ◽

Energy Metabolism ◽

Food Intake ◽

Body Mass ◽

Body Fat ◽

Fat Mass ◽

Tree Shrew ◽

Control Level ◽

Body Fat Mass ◽

Serum Leptin

To investigate the effect of fasting and re-feeding on energy metabolism and thermogenesis in the tree shrew (Tupaia belangeri), the changes in body mass and body fat mass, resting metabolic rate (RMR), non-shivering thermogenesis (NST), body composition, mitochondrial cytochrome c oxidase (COX) activity in liver and brown adipose tissue (BAT), uncoupling protein-1 (UCP1) content of BAT, serum leptin level and post-fasting food intake were monitored and measured. The results showed that fasting induced a significant reduction in body mass and body fat mass. Body mass was restored to the control level in re-feeding tree shrew except for the body fat. RMR and NST decreased significantly in response to fasting, and returned to the control level after re-feeding. Fasting induced significant reduction in total, but not specific, COX activity (nmol O2/min/total tissue) in liver and BAT, and UCP1 content in BAT, which was reversed after re-feeding 48 h. Fasting of 12 h induced a rapid reduction in serum leptin content. There were no post-fasting compensatory increases in food intake. Interestingly, the tree shrew did not recover adipose tissue mass, nor serum leptin levels, upon re-feeding. These results suggest that T. belangeri can adjust the status of its physiology integratively to cope with the lack of food by means of decreasing body mass, adaptive thermogenesis and serum leptin levels, and serum leptin level acted as a starvation signal to mediate predominantly the reduction in body mass and energy expenditure.

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