南方鲇的饥饿代谢研究

STARVATION METABOLISM IN THE SOUTHERN CATFISH ( SILURUS MERIDIONALIS )

于 1 996年 1月 9日— 6月 1 2日 ,在西南师范大学鱼类能量学实验室 ,对南方鲇幼鱼( 61 7— 92 3g)进行了 2 7 5℃条件下的饥饿耐受性实验 ,并采用连续流水式呼吸仪测定了实验鱼在此期间的静止代谢率。结果表明 ,饥饿至 1 56d时 ,50 %的实验鱼死亡。饥饿鱼代谢水平的变化可分为 4个阶段 :( 1 )饥饿 1— 2 0d ,代谢率随饥饿时间延长而呈直线下降 ;( 2 )饥饿2 1— 81d ,处于相对稳定状态 ;( 3)饥饿 81— 91d ,代谢率再度明显下降 ;( 4 )饥饿 91— 1 56d ,代谢率在一个更低水平又处于相对稳定状态 ,直至半数死亡。作者认为南方鲇在饥饿过程中代谢率出现的高低两个相对稳定期是南方鲇适应食物缺乏环境的能量生态学对策 ,并把高稳定期称为“饥饿适应代谢” ,低稳定期称为“存活代谢”。在 2 7.5℃条件下 ,南方鲇的这两个特征值分别为 66.6mgO2 / (kg·h)和 52 .9mgO2 / (kg·h)。

A starvation experiment was conducted on young southern catfish ( Silurus meridionalis Chen) with initial weights of 61 7—92 3g at 27 5℃, at the Laboratory of Fish Energetics of the University,from January 9 to June 12,1996. The metabolic rate of the fast tested fish was measured with a continuous flow respirometer. Half of the tested fish starved to death when the fast experiment lasted for 156 days,and the metabolic rate decreased from 137 2 to 47 9mgO 2/(kg·h). The level of metabolism in the duration of starvation could be divided into four phases:(1) from the 1st day to the 20th day, the metabolic rate decreased dramatically;(2) from the 21st day to the 81st day,the metabolic rate kept relatively stable;(3) from the 81st day to the 91st day,the metabolic rate decreased obviously; and (4) from the 91st day to the 156th day,the metabolic rate became relatively stable at a lower level. The mean value difference between the two stable phases was statistically significant. The results suggest that alternation of metabolic level in the fast tested fish from higher phase,“Starvation-adapting metabolism”,to the lower one,“Survival metabolism”,was the energetic-ecological strategy to adapt starvation. At 27 5℃,the metabolic level at the two phases in southern catfish were 66 6 and 52 9mgO 2/(kg·h),respectively.