温度及光照驯化对南方鲇线粒体代谢补偿调节的影响

MITOCHONDRIAL METABOLIC COMPENSATION OF THE SOUTHERN CATFISH,SILURUS MERIDIONALIS CHEN,IN RESPONSE TO ACCLIMATION OF TEMPERATURE AND PHOTOPERIOD

为了检验在季节驯化中温度和光周期分别对南方鲇(Silurus meridionalis Chen)组织线粒体代谢补偿效应的调节作用,研究对实验鱼进行了4个系列的驯化处理:(1)低温等光周期[12.5℃,12L︰12D,体重:(186.36±2.77)g];(2)高温等光周期[27.5℃,12L︰12D,体重:(202.80±7.99)g];(3)短光照中等温[8L︰16D,20℃,体重:(284.80±13.47)g];(4)长光照中等温度[16L︰8D,20℃,体重:(283.70±15.60)g],每组均为24尾鱼。驯化8周后取样,测定了各驯化组鱼体心脏、肝脏和肾脏的器官质量(器官指数),以及这3种器官组织线粒体在测定温度为12.5℃、20℃和27.5℃时的呼吸率和细胞色素C氧化酶(CCO)活性。结果显示,在等光周期条件下,低温驯化组(12.5℃,12L︰12D)实验鱼的心脏、肝脏和肾脏的器官指数均显著高于高温驯化组(27.5℃,12L︰12D);在中等温度条件下不同光照处理的实验鱼之间器官指数无显著差异。在中等温度条件下短光照驯化组(8L︰16D,20℃)鱼体的心脏、肾脏和肝脏组织线粒体呼吸率和CCO活性均显著高于长光照组(16L︰8D,20℃);而在等光周期条件下的不同温度驯化并没引起这3种组织线粒体的呼吸率和CCO活性的明显差异。综合认为:在季节驯化过程中,光周期改变是引起线粒体代谢能力的主要因素,温度变化则是调整器官组织重量的主要因素,光周期与温度对南方鲇线粒体代谢机制的调整具有协同作用。

To evaluate the effects of ambient temperature and day-length respectively in setting metabolic compensation of mitochondria in juvenile of the southern catfish（Silurus meridionalis Chen）,the organ index of the heart,kidney and liver and their state 3 rates of mitochondria and cytochrome C oxidase activity（CCO） were measured in the tested fishes at different acclimations.Two experimental groups were acclimated to high temperature（27.5℃） and low temperature（12.5℃） at equivalent photoperiod（12L︰12D）,and other two groups were kept at long day-length（16L︰8D） and short day-length（8L︰16D） condition at same moderate temperature（20 ℃）.There were 24 individuals in each group.Fish were maintained at these acclimation conditions for 8 weeks before sampling.In condition of the equivalent photoperiod,the organ index of the heart,kidney,and liver in the cold-acclimatized group（12.5℃,12L︰12D） were all significantly higher than that in the warm group（12L︰12D,27.5℃）（P ＆lt; 0.05）.The acclimation of day-length did not cause any change in organ mass at same moderate temperature.At assay temperature of 12.5,20,and 27.5℃,both state 3 rates of mitochondria and activity of CCO in the heart,kidney,and liver in the short day-length group（8L︰16D,20℃） were significantly higher than those in long day-length group（16L︰8D,20℃）.State 3 rates of mitochondria and activity of CCO in the three tissues were not influenced by thermal acclimation.The results showed that day-length initiates changes in the mitochondrial oxidative capacity and the temperature was the major ambient factor to alter the organ mass.It is suggested that during seasonal acclimatization photoperiod signal and thermal condition might have a cooperative effect on the adjustment for metabolic compensation in the southern catfish.