温度和饥饿对鲤鱼幼鱼静止代谢率及自发运动的影响

The Influence of Temperature and Starvation on Resting Metabolic Rate and Spontaneous Activity in Juvenile Cyprinus carpio

分别在15和25℃条件下对鲤鱼(Cyprinus carpio)幼鱼[体重(10.36±0.22)g,n=88]进行2周的饥饿处理(饥饿组)或持续投喂(对照组),然后对实验鱼的静止代谢率(resting metabolic rate,RMR)进行了测定,同时以活动期的胸鳍﹑尾鳍摆动频率,观察期(10 min)胸鳍﹑尾鳍平均摆动次数,和运动时间比为指标对实验鱼的自发运动进行了观察。研究发现:温度和饥饿均显著影响鲤鱼幼鱼的静止代谢率(P<0.05);在15与25℃条件下饥饿分别导致静止代谢率下降了19%和20%;温度由15℃上升至25℃,对照组与饥饿组静止代谢率分别增加了83%和80%。在15与25℃条件下,饥饿对鲤鱼幼鱼的自发运动具有显著不同的影响(P<0.05),且胸鳍和尾鳍的结果十分相似;在15℃饥饿组与对照组的胸鳍、尾鳍摆动频率(活动期,以下类同)均无显著差异,而饥饿组运动时间比显著低于对照组,导致饥饿组的胸鳍、尾鳍平均摆动次数(观察期,以下类同)均显著低于对照组(P<0.05);而在25℃饥饿组的胸鳍、尾鳍摆动频率均显著高于对照组,运动时间比无显著差异,导致饥饿组的胸鳍、尾鳍平均摆动次数均显著高于对照组(P<0.05)。研究结果提示,在15℃下鲤鱼幼鱼通过降低自发运动以降低能量消耗来适应饥饿,而在25℃条件下,鲤鱼幼鱼通过增加自发运动来增大获取食物的机率以应对饥饿,这可能与野外环境中不同温度下食物丰富度及鲤鱼幼鱼的生理状况有关,但静止代谢率并未呈现与自发运动相关联的变化。

The resting metabolic rate （RMR） of both starvation （2 weeks） and control juvenile Cyprinus carpio [body mass 10. 36 ± O. 22 g, n = 88] were measured at both 15 and 25℃, respectively. The spontaneous activity indicated by fin （both pectoral and tail fins） beat frequency during movement （ FBF ）, average fin beat times during whole 10 rain observation period （FBF10_min） and percent time spent moving （PTM） were measured at the same time. Both the temperature and starvation showed significant effects on RMR （P 〈 O. 05）. The RMR of starved fish exhibited a similar 19% - 20% decrease compared to that of control fish atboth 15 and 25℃ , respectively, while the RMR of control and starved fish increase by about 80% -83% with the increase of temperature. The starvation has significantly different effect on spontaneous activity at different temperature （P 〈 0. 05）. When acclimated at 15℃ , starvation treatment showed no effect on FBF , while it elicited a significantly lower PTM, resulting in a significantly lower FBF10_min in starved fish. However, starvation treatment showed no effect on PTM while it elicited a significantly higher FBF resulting in a significantly higher FBF10_min in starved fish acclimated at 25℃. It suggested that when undergo starvation, the juvenile C. carpio reduce its spontaneous activity to save energy at 15℃ , but increase its spontaneous activity possibly for food hunting at 25~C. The different responses of spontaneous activity to starvation of fish acclimated at different temperature may be related to the richness of food resources and physiological status condition of fish in wild environment at different temperature. However, starved fish showed a similar RMR response to temperature change when compared to control fish.