关键词: 体脂累积, 高脂食物, 非颤抖性产热, 黑线仓鼠, 温度

Abstract: Adaptive regulation of energy metabolism is employed by small mammals to cope with seasonal environmental changes. In order to explore the strategy of trade-off between the energy expenditure of metabolic thermogenesis and body fat content, three experiments were designed using adult male hamsters. In experiment 1, animals were subjected to high or low-fat diet (HF or LF); in experiment 2, animals were exposed to either cold (5℃) or warm temperature (30℃); in experiment 3, animals were fed with high fat diet and transferred into a cold temperature (5℃). Food intake, energy intake and digestibility were measured using a food balance method; metabolic thermogenesis was measured using an open-flow respirometry system; body fat content was measured by ether extraction in a Soxhlet apparatus. The results showed that, in experiment 1, food intake was significantly reduced, but body fat content increased in HF group compared to that in LF group. In experiment 2, animals consumed significantly less food at the warm, but showed higher fat content than cold group. However, they increased energy intake and nonshivering thermogenesis, but decreased fat content in the cold compared to that in warm. In experiment 3, the HF hamsters showed significantly higher energy intake and nonshivering thermogenesis, but lower body fat content at the cold compared to the hamsters maintained at room temperature. These findings indicated that the effect of high fat diet on body fat accumulation was dependent on ambient temperature. The exposure to the cold induced body fat mobilization and the warm exposure increased fat storage. The striped hamsters increased thermogenesis at cold, but it was not completely compensated by energy intake, resulting in a significant elevation of fat mobilization. The reduction of thermogenesis when warm was the main factor inducing fat accumulation. The energy expenditure associated with metabolic thermogenesis played more important roles in body fat regulation than energy intake.

Key words: Body fat content, High fat diet, Nonshivering thermogenesis, Striped hamsters, Temperature