横断山不同海拔地区大绒鼠面对高糖食物变化的生理和行为响应

野外小型哺乳动物通常会表现出生理和行为的变化以应对环境条件的季节性变化,如食物、温度、光照等.为了研究横断山不同地区大绒鼠(Eothenomys miletus)面对不同含糖量食物时的生理和行为适应策略,选取云南剑川和香格里拉地区大绒鼠各26只,喂高糖食物28 d后重喂标准食物28 d,实验共56 d.测定大绒鼠的体重...

Physiological and Behavioral Responses of Eothenomys miletus in Different Elevations of Hengduan Mountain to High-sugar Diet

Small mammals in the wild often show physiological and behavioral changes in response to seasonal environmental variations, such as food, temperature, and photoperiod. To investigate the physiological and behavioral adaptation strategies of Eothenomys miletus in different regions of Hengduan Mountain regions in response to different sugar foods, E. miletus in Jianchuan and Xianggelila were fed a high-sugar diet for 28 d and returned to a standard food for another 28 d, and then their body masses, food intakea, resting metabolic rates (RMR) and activity behaviors were measured. Moreover, serum leptin levels, hypothalamic neuropeptide gene expressions and body compositions were measured on day 0, 28 and 56. Food intake was measured by food balance method, hypothalamic neuropeptide gene expression was measured by real-time fluorescence quantitative polymerase chain reaction (RT-PCR). Data were analyzed by two-way ANOVA or two-way ANCOVA, and associations were judged by Pearson-correlation analysis. The results showed that high-sugar diet could significantly increase the body mass (F1, 907 = 8.11, P < 0.01) (Fig. 1) and food intake (F1, 907 = 1034.94, P < 0.01) (Fig. 2) of the E. miletus in the two regions, but had no significant effect on RMR and activity behavior. After refeeding standard food, the body mass of Xianggelila E. miletus could be restored to the level of standard diet group, while the body mass of Jianchuan E. miletus was still higher. Leptin was positively correlated with body mass (r = 0.80, P < 0.01) (Fig. 5), but not with neuropeptide expression (P > 0.05). In addition, the physiological characteristics of the E. miletus in the two regions also showed regional differences: The E. miletus in Xianggelila had lower body mass (F1, 907 = 842.02, P < 0.01) (Fig. 1) than those in Jianchuan region, but RMR (F1, 907 = 6779.51, P < 0.01) (Fig. 3) and activity behavior (F1, 907 = 79.89, P < 0.01) (Fig. 4) were higher than in Jianchuan area, the higher food intake (F1, 907 = 49.96, P < 0.01) (Fig. 2) may be related to the higher expression of neuropeptide Y (F1, 36 = 4.672, P < 0.05) (Table 3). All of the results showed that body mass of E. miletus in two regions increased when they were exposed to the high-sugar food, but change of body mass in the two regions was significantly different after refeeding, showing a great difference between E miletus in the two regions. Leptin and NPY expression levels may play an important role in body mass regulation and energy balance in E. miletus. Location-determined environmental factors (food resources, temperature, and altitude) may be critical for determining phenotypic differences between biological regions and their adaptation to extreme environmental conditions.