中文摘要：

为了考查鱼类对温度变化的功能适应和生理反应特征,以不同驯化温度（10、20和30℃,驯化两周）为对照,进行双向急性变温处理（20℃→10℃和20℃→30℃）,分别在不同时间（0.5、1、2、4、8和24h）对南方鲇（Silurus meridionalis Chen）幼鱼静止耗氧率（Resting oxygen consumption rate,VO2）进行测定并在处理后及时测定实验鱼的临界游泳速度（Critical swimming speed,Ucrit）。研究发现：不同驯化温度下实验鱼的Ucrit随驯化温度升高呈显著增加的变化趋势,相对临界游泳速度（Relative critical swimming speed,Ur）分别为1.83、2.87和3.37 BL/s（Body length per second）（P〈0.05）;双向急性变温两组的Ur分别与驯化组均无显著差异（P〉0.05）;Ur与温度的关系表达为：Ur=0.8114T＋1.0976（n=37,R2=0.973,P〈0.05）。VO2也随驯化温度升高呈显著增加的变化特征,分别为14.91、28.34和44.98 mg O2/kg·h（P〈0.05）。双向急性变温对VO2的影响十分显著。急性升温组的静止耗氧率呈现先上升后下降并趋稳定的变化规律,其静止耗氧率的Q10值的峰值（3.1）出现在升温后的0.5h,是对照组的1.96倍;而急性降温组的静止耗氧率则急剧连续下降至相对稳定水平,其Q10值的峰值（4.8）出现在降温后的1.0h,是对照组的2.5倍。研究表明：在相同的变温幅度下,双向急性变温对南方鲇幼鱼均存在明显的生理胁迫;不同温度变化方向的代谢反应特征却不尽相同,急性降温对南方鲇幼鱼造成的生理胁迫可能大于急性升温;当环境温度发生骤然变化时,实验鱼的运动生理功能具有较好的温度适应能力。研究提示,迅速降温后水流刺激可能会终止鱼类的＂冷休克＂,引起整体的代谢水平的重新调节,以满足运动的能量需求并提高生存适合度。

英文摘要：

The effects of short-term acute temperature change（20℃→10℃ and 20℃→30℃） and long-term temperature acclimation（10,20 and 30℃,two weeks） on resting oxygen consumption rate（Resting oxygen consumption rate,VO2） and critical swimming speed（Critical swimming speed,Ucrit） of juvenile southern catfish（Silurus meridionalis Chen） were conducted to examine the different physiological responses of fish underwent acute and chronic temperature change.The results of present study showed that the relative critical swimming speeds（Relative critical swimming speed,Ur） of 10,20 and 30 ℃ acclimation group were 1.83,2.87 and 3.37 BL/s（Body length per second）（P0.05）,respectively.The Ur of both acute temperature elevation group and acute temperature decline group was not significantly different from that of corresponding acclimation group（P0.05）.The relationship between Ur and acclimation temperature showed as Ur =0.8114T＋ 1.0976（n=37,R2 = 0.973,P0.05）.The VO2 increased profoundly with temperature（P0.05） and those values were 14.91,28.34 and 44.98 mg O2/kg·h,respectively.Both acute high temperature exposure and acute cold temperature exposure have a significant influence on VO2 of juvenile southern catfish.The VO2 of acute temperature elevation group firstly increased and then decreased slowly to a relative stable VO2.The peak value（3.1） of Q10 of VO2 in high temperature exposure group appeared at 0.5h after acute temperature change and was about two folds that of control group while the peak value（3.1） of Q10 of VO2 in acute temperature decline group appeared at 8h after acute temperature change and was about four folds that of control group.It suggested that acute temperature change exerted a profoundly influence on the metabolic physiological process of juvenile southern catfish.The metabolic responses to acute temperature decline group differed significantly from that of acute temperature elevation group.The physiological stress elicited by acute temperature dec