不同海拔地区高原鼠兔热中性区及静止代谢率的差异

高原地区动物面临一系列严峻的生存考验,随着海拔的变化,动物栖息地的食物资源等差异大,温度、氧分压等环境因子都将发生变化.环境差异可能会影响动物种群的生活史对策.在生理功能适应中,动物的能量代谢适应扮演着重要的角色.为探究高原鼠兔(Ochotona curzoniae)在不同海拔地区的能量代谢适应与热中性区范围,分别选取...

Plateau Pika, Ochotona curzoniae; Resting metabolic rate; Thermal neutral zone; Thermal conductance; Altitude

Objectives]Animals which inhabit in plateau are facing with the unique environmental challenges such as low temperature and hypoxia.As the rising of altitude,these challenges may increase.The metabolism of animals plays an important role during long-term physiological adaptation.With the changes of altitude,the metabolic rates of many animals vary synchronously to adapt to different habitats.However,it is still unclear whether the animal thermal neutral zone(TNZ)changes with altitude.In this study,we took Plateau Pikas(Ochotona curzoniae)as studying objects to test how their thermal neutral zone range changes at different altitudes.Methods]We examined the physiological traits of Plateau Pikas by measuring body temperature(T_b),metabolic rate and thermal conductance(C).Resting metabolic rates(RMR)were measured using 8-channel FMS portable respiratory metabolic system(Sable Systems International,Henderson,NV,USA).Biochemical incubators(LHR-250,Shanghai Yiheng Scientific Instruments Co.,LTD.)was used to adjust the chambers’temperature(Ta)within±0.5℃.Experiments were conducted under 15.0℃,20.0℃,22.5℃,24.0℃,25.0℃,26.0℃,27.5℃,29.0℃,30.0℃,31.5℃,32.5℃and 35.0℃,respectively.The differences of metabolic rate among each group at ambient temperature were analyzed by repeated measure ANOVA,the differences between resting metabolic rate and body weight at different altitudes were analyzed by one-way ANOVA.Results]The results showed that the body mass of Plateau Pikas at high or medium altitude region was significantly higher than that of low altitude region(Fig.3).The body temperature of Plateau Pikas at three altitude regions continuously increased with the increase of ambient temperature(Fig.1).Compared with high and medium altitude regions,Plateau Pikas at low altitude region had a lower metabolic rate(Fig.3).The thermal neutral zone of Plateau Pikas was 24-30℃at both high and middle altitude regions,while it was 25-30℃at low altitude region(Fig.2).The thermal conductance of Plateau Pikas at three altitude regions continuously increased with the increase of ambient temperature(Fig.4).The thermal conductance was the lowest and stable when the ambient temperature was between 15℃and 29℃,the mean thermal conductance values at high,middle and low altitude were(0.18±0.09)ml/(g·h·℃),(0.19±0.09)ml/(g·h℃)and(0.19±0.08)ml/(g·h·℃),respectively.Conclusion]This study found that as the rising of altitude,both metabolic rate and thermal neutral zone of Plateau Pikas increased to adapt to colder environment at higher altitude regions.These results provide basic information for understanding the physiological adaptation of animals at different altitude regions.