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Lactation is the most energetically demanding period in small mammals. To investigate the energy balance strategies in lactating Apodemus chevrieri, we compared body mass, energy intake, thermogenic capacity, organ mass and other morphological parameters of the digestive tract of reproductive and non-reproductive females. The results showed that at parturition, mean body mass was 23.89% higher than that of the non-reproductive group. Over the course of the lactation period (from day 0 to day 21), females decreased by 24.30% in body mass and increased by 21.46% in resting metabolic rate (RMR), then all reached the original levels at day 30. Non-shivering thermogenesis (NST) decreased significantly and reached a minimum at peak lactation (on day 21). During lactation, mean NST was 18.55% lower than that of the non-reproductive group. At the same time, lactating A. chevrieri increased their energy intake significantly. Energy intake increased after parturition and reached a maximum at day 21 of lacta...

The value of phenotypic plasticity in energy metabolism and behavioral patterns in response to variations of food availability was handled in adult male voles (Eothenomys miletus) acclimated to random food deprivation (FD) for 4 weeks. During this period, in which voles were fed ad libitum for a randomly assigned 3 days each week, changes in body mass, food intake, resting metabolic rate (RMR), non-shivering thermogenesis (NST) and serum leptin levels were measured. Behavioral observations were made to examine behavioral patterns including activity, feeding, grooming and resting behaviors. The results showed that food intake and gastrointestinal mass increased significantly, but RMR and NST decreased significantly in the FD group compared to the control group. Moreover, the FD group had a significantly higher percentage of feeding behavior and lower activity than those in control group. In addition, serum leptin levels were positively correlated with body fat mass, but showed no significant differ...

To test the hypothesis that mammals that show decrease in body mass under short-day condition should be resistant to high-fat induced obesity, we traced the changes of energy balance in a wild rodent, Apodemus chevrieri, which were acclimated to either long day [16 light (L):8 dark (D), LD] or short day (8 L:16D, SD) and fed either a low-fat diet (LFD) or high-fat diet (HFD) in each photoperiodic manipulation. We found that A. chevrieri was not resistant to high-fat diet-induced obesity, and SD, not HFD, induced the elevation in basal metabolic rate (BMR), nonshivering thermogenesis (NST) and uncoupling protein-1 (UCP1) content in brown adipose tissue (BAT). HFD caused the increase in apparent digestibility and body fat mass, and the decrease in energy intake in both LD and SD A. chevrieri. The enhancement of energy absorption associated with small intestine tissue recruitment can compensate the lower energy intake, which may contribute to the high-fat diet-induced body fat deposition. Thus, a dec...

To investigate the effect of food restriction on the body mass, thermogenesis and serum leptin level in Apodemus chevrieri, the changes of body mass, body fat mass, resting metabolic rate (RMR), mitochondrial cytochrome coxidase (COX) activity both in liver and brown adipose tissue (BAT), uncoupling protein1 (UCP1) content of BAT, and serum leptin level were measured. The results showed that food restriction induced significant reductions in body mass and body fat mass. RMR decreased significantly in response to food restriction, and food restriction induced significant reduction in total mitochondrial protein content, COX activity both in liver and BAT, and UCP1 content in BAT. Food restriction also induced a reduction in serum leptin level. In contrast, length and mass with content in the small intestine in the food-restricted group was significantly higher relative to the control group. It suggests that the physiological regulations in energy metabolism to adaptively cope with a period of food...

Mammals, including rodents, are able to maintain a stable body mass, which is a result of balance between energy intake and energy expenditure. Exercise training can increase energy expenditure and is considered one of the most important factors affecting energy balance in mammals. In order to understand the effect of exercise on body mass regulation and energy metabolism, changes of body mass, metabolic rate, energy intake, serum leptin levels and body composition were measured in Apodemus chevrieri during an 8-week forced exercise training with a treadmill. The results showed that exercise training had no significant effects on body mass, but the metabolic rate and energy intake were increased during the 8-week exercise training. Body fat mass and serum leptin levels decreased in the exercise group compared to the control group. There was a positive relationship between serum leptin levels and body fat mass in the control group, but no relationship in the exercise group. Mass of liver and diges...

Environmental cues play important roles in the regulation of an animal's physiology and behaviour. The purpose of the present study was to test the hypothesis that ambient temperature was a cue to induce adjustments in body mass, body temperature and thermogenic capacity, associated with changes in serum leptin levels in the tree shrew (Tupaia belangeri chinensis). The results showed that the tree shrew increased resting metabolic rate (RMR), nonshivering thermogenesis (NST) and body mass when exposed to the cold. Uncoupling protein 1 (UCP1) content of brown adipose tissue (BAT) increased in the cold exposure. Also serum leptin levels were positively correlated with body mass. Together, these data supported our hypothesis that ambient temperature was a cue to induce changes in body mass and metabolism. Serum leptin participated in the regulation of energy balance and body weight in the tree shrew.