饥饿过程鲇鱼幼鱼静止代谢、身体组成及与力竭性运动后过量耗氧的关系

THE RELATIONSHIP AMONG RESTING METABOLIC RATE,BODY COMPOSITION AND EXCESS POST-EXCESS OXYGEN CONSUMPTION DURING FASTING IN SILURUS ASOTUS

将33尾鲇鱼(Silurus asotus)幼鱼(32.14±1.40)g在(25±1)℃条件下驯化2周后分5组(0、1、2、4、8周)进行饥饿处理;分别测定了各处理组实验鱼的静止耗氧率、力竭性运动后的过量耗氧(EPOC)并对鱼体组成进行了分析。实验结果显示:各处理组实验鱼的静止耗氧率分别为(2.21±0.15)、(1.63±0.04)、(1.64±0.13)、(1.44±0.08)、(0.98±0.09)mgO2/kg·min,其中饥饿1、2、4周组之间无显著差异,却都显著低于0组、高于8周组的水平(P<0.05),呈现一个静止代谢"平台期";鱼体组成的变化表明,该"平台期"的主要供能物质为脂肪,其后则主要由蛋白质供能;各组实验鱼力竭性运动后耗氧率峰值(VO2 peak)立即(2min)出现,随后逐渐下降至稳定耗氧水平(VO2 steady),EPOC总量(Excess VO2)分别为(31.8±6.06)、(76.67±4.34)、(69.2±5.89)、(70.41±3.12)、(38.28±2.72)mgO2/kg,其中饥饿1、2、4周组均显著高于饥饿0和8周组的水平(P<0.05),出现无氧运动功能补偿的"效应期"。通过鲇鱼幼鱼静止代谢"平台期"与其功能补偿"效应期"在时间上完全吻合的现象,揭示鱼类的功能补偿效应与其静止代谢水平之间存在的密切关联。

The resting metabolic rate （VO2rest）, body composition and excess post-exercise oxygen consumption（EPOC）of 33 juvenile Silurus asotus （32.14±1.40）g were investigated after 0, 1, 2, 4 and 8 weeks’ starvation under （25±1）℃. VO2rest were （2.21 ± 0.15）, （1.63 ± 0.04）, （1.64 ± 0.13）, （1.44 ±0.08） and （0.98 ± 0.09） mgO2/kg/min after 0, 1, 2, 4 and 8 weeks’ starvation, respectively. There were no significant difference in VO2rest among 1, 2 and 4 week starvation groups, whereas, all the three groups were significantly lower than that of 0 week group but significantly higher than that of 8 week group （P〈0.05）. Combined the above results with which of body composition, it suggested that there existed a “stable period” in VO2rest during long term starvation, and the energy expenditure in this period was mainly provided by catabolism of lipid rather than protein, which might play a more important role in energy supply after “stable period”. The oxygen consumption was immediately increased to peak value at 2 min after exhaustive exercise and slowly de-creased to a stabilized level. The excess post-exercise oxygen consumptions were （31.8 ± 6.06）, （76.67 ± 4.34）, （69.2 ± 5.89）, （70.41 ± 3.12） and （38.28 ± 2.72） mgO2/kg after 0, 1, 2, 4 and 8 weeks’ starvation, respectively. The excess post-exercise oxygen consumptions of 1, 2 and 4 week starvation groups were significantly higher than both those of 0 and 8 week groups （P〈0.05）, which suggested there was a “exhibition period” in function compensation. The time course of “stable period” in VO2rest and “exhibition period” in function compensation were identical, which suggested that there existed close relationship between metabolic expenditure and physiological function compensation in Silurus asotus.