关键词: 小毛足鼠, 能量代谢, 体温调节, 基础代谢率, 非颤抖性产热

Abstract: In order to understand the adaptive ecophysiological characteristics of desert hamsters ( Phodopus roborovskii) lived in Hunshandake desert of Inner Mongolia , we measured the energy metabolism and thermoregulation of adult hamsters. Metabolic rates were measured at a temperature range from 7 to 35℃using the closed-circuit respirometer , and the nonshivering thermogenesis was induced by subcutaneous injection of norepinephrine. The energy intakes were estimated with food trials. The body masses and body temperatures of animals were measured before and after each experiment. The thermal neutral zone (TNZ) of desert hamsters was 25 to 33 ℃, basal metabolic rate (BMR) was 2.61 ±0.04 (mlO₂/ g·h) , which is 152 % and 180 %of the values predicted by Hayssen &Lacy (1985) and McNab (1988) based on body mass , respectively. Mean body temperature of desert hamsters at the temperature range of 7 to 31 ℃was 35.7 ±0.1 ℃. The minimum thermal conductance within the temperature range of 7 to 25 ℃was 0.21 (mlO₂/ g·h·℃) , which is 98 % of that predicted by Bradley &Deavers (1980 ) . The maximum nonshivering thermogenesis of desert hamsters was 8.53 ±0.28 mlO₂/ g·h , which is 114 % of the value predicted by Heldmaier (1971) based on body mass , and the nonshivering thermogenesis scope (ratio of maximum NST to BMR) was 3.3. The energy intake ,digested energy , and metabolizable energy intake was 2.26 ±0.12 kJ / g·d , 2.18 ±0.13 kJ / g·d , and 2.13 ±0.12 kJ / g·d , respectively , while the digestibility and metabolizable energy efficiency was 97±0.2 %and 94 ±1.2 % , respectively1 Digestibility is higher in desert hamsters than other rodent species. No significant relationship between basal metabolic rate and digested energy was detected and , however , there was a significant relationship between minimum thermal conductance and energy intake ,digested energy , and metabolizable energy intake. These results suggest that high BMR and NST, wider TNZ, lower low critical temperature , relative lower body temperature , thermal conductance equal to the predicted value , and high digestibility can enable desert hamsters to live in an arid environment with high fluctuations in environment temperature and food resources.

Key words: Desert hamster ( Phodopus roborovskii), Energy metabolism, Thermoregulation, Basal metabolic rate, Nonshivering thermogenesis