Abstract:

The significance of plasticity in energy metabolism and behavioral patterns in response to variations of food availability was examined in adult male KM mice acclimated to random food deprivation (FD)for 4 weeks,in which animals were fed ad libitum for a randomly assigned 3 days each week,but were deprived of food for the other 4 days, and then refed ad libitum for another 4 weeks. Food intake was measured using the food balance method,and basal metabolic rate (BMR) and nonshivering thermogenesis (NST)were measured using a closed-circuit respirometer. Behavioral observations were made to examine behavioral patterns including activity, feeding, grooming and resting behavior. The data showed that food intake and gastrointestinal mass increased significantly, and BMR and NST decreased significantly in FD mice compared to controls. Moreover, FD mice had a significantly higher percentage of resting behavior and lower activity than control mice. These parameters were all recovered after 4 weeks of ad libitum re-feeding, indicating significant plasticity. These results suggest that animals can compensate for an unpredictable reduction of food availability by engaging in an energetic strategy, including an increase in energy intake related to food intake, and a decrease in energy expenditure associated with BMR, NST and activity, but not including body fat mobilization. Significant plasticity in energy metabolism and behavioral patterns is shown in mice over a short timescale, which plays an important role in adaptations to food shortage in unpredictable environments with relation to food availability.

Key words: Behavior, Energy metabolism, Food restriction, KM mice, Plasticity, Re-feeding, Thermogenesis

摘要： 为阐明能量代谢和行为的可塑性对动物适应食物资源变化的意义,将成年雄性KM 小鼠随机饥饿驯化4
周,再重喂食驯化4 周。采用食物平衡法测定摄食量、封闭式流体压力呼吸计测定基础代谢率(BMR) 和非颤
抖性产热(NST)、观察法测定行为。随机饥饿使摄食量、消化道重量显著增加,BMR 和NST 显著降低。与对照
组相比,饥饿组休息行为显著增加,活动显著降低。重喂食后,上述指标均恢复到对照组水平,表现出显著的
可塑性。研究结果表明,动物适应难以预测的食物资源短缺的主要策略包括:增加自由取食期间的摄食量;降
低BMR、NST 和活动行为,从而保存身体贮存的能量。能量代谢和活动行为在较短的时间尺度内表现出显著的
可塑性对小鼠适应不可预测的食物资源短缺的应激环境具有重要意义。

关键词: 饥饿, 能量代谢, 产热, 行为, 重喂食, 小鼠, 可塑性