锦鲫的摄食代谢与运动代谢及其相互影响

为了探讨锦鲫(Carassius auratus)幼鱼摄食后特殊动力作用(SDA)的变化特征及运动代谢与摄食代谢之间的相互影响,实验首先灌喂锦鲫4%体重的饲料和等体积的纤维素(湿重),测定灌喂前后的耗氧率;另设灌喂饲料、灌喂纤维素、空腹组(对照组)3个组,测定3组的临界游泳速度(Ucrit)和运动耗氧率(MO2);然后在70%、0%临界游泳速度下,分别测定饱足摄食组和空腹组的耗氧率。结果显示:1灌喂饲料后代谢率快速上升,达到峰值后又迅速下降,代谢时间较短,没有一个相对稳定的平台期,灌喂纤维素后代谢率没有显著性变化(P0.05)。提示锦鲫幼鱼的特殊动力作用功率曲线为一个典型的"三角型"模型,且在特殊动力作用总耗能中,生化特殊动力作用占特殊动力作用总耗能的绝大部分,而机械特殊动力作用只占特殊动力作用的极少部分。2锦鲫幼鱼在摄食后临界游泳速度显著下降(P0.05),代谢率显著升高(P0.05)。摄食后的运动过程中,代谢率从摄食开始到代谢率回落至空腹组代谢的标准误范围内的首个数据所对应的时间长度均为6.5 h,且摄食代谢无显著性差异。提示,对锦鲫幼鱼来说,摄食代谢降低了其运动能力,而运动代谢并没有影响摄食代谢。

The Interaction between Feeding and Locomotive Metabolism in Goldfish (Carassius auratus)

The aims of the present study were to investigate the characteristic of the specific dynamic action (SDA) and the interaction between feeding and locomotive metabolism in goldfish (Carassius auratus). Firstly, goldfish was force-fed with 4% body mass of either compound feed or cellulose and the pre-feeding and postprandial oxygen consumption rate (Vo2) were measured to identify the characteristic of SDA. Then, the critical swimming speed (Ucrit) and swimming metabolic rate (MO2) at different swimming speed of fasting and fed fish were measured to identify the effect of digestion on locomotive metabolism. Lastly, the postprandial metabolisms of fasting or digesting fish swum under either 70% or 0% Ucrit were measured, aiming to identify the effect of swimming on feeding metabolism. The effect of locomotive on feeding metabolism and the effect of force-feeding with compound feed or cellulose on SDA were determined by paired t-test, whereas the effect of experiment treatments on active metabolic rate was determined by t-test. Effects of experimental treatment, swimming speed and (or) sample time on Ucrit or MO2 were determined by a analysis of variance (ANOVA) which followed by Duncan multiple-comparison posthoc test if it was necessary. The results showed that the SDA increase shortly after force-feeding of compound feed which lasted about 7 h while force-feeding of cellulose elicited no significant change in MO2 (Fig 1), suggesting mechanical SDA contributes little to SDA magnitude while biochemical SDA is the main components of SDA in gold fish. Ucrit decreased significantly while swimming MO2 increased significantly at any given swimming speed in fed fish compared with those of fasting fish. However, neither duration nor increment of SDA showed any significant difference between resting and swimming fish (70% Ucrit). The duration calculated as the time from feeding to when the metabolic rate returned to within the standard error of the resting metabolic rate of a given fish were both 6.5 h, and the feeding metabolism at any given sample time showed no significant difference (Fig 4). The present study demonstrates clearly that in goldfish, digestion shows profound negative effect on locomotive metabolism while locomotion shows little effect on feeding metabolism.