Studies on fish feeding rhythms and their application

1.鱼可以通过操作性条件反射学习按需摄食。我们采用按需饲养法饲养红鱼、金鱼和马苏鲑鱼。同时记录动物的摄食和活动节律。结果表明：(1)无论是个体还是群体，这些物种都很容易学会按需取食。只有用这种方法，我们才能把它们保存得更久。(2)按需投喂的生长速度明显好于常规限制投喂方式，尤其是金鱼。(3)在恒定条件下，它们的摄食活动和活动活动均存在昼夜节律，表明这些物种存在生物钟。多个振荡器参与鱼类的运动、摄食和生理功能的昼夜节律系统。然而，振荡器和函数之间的相关性仍然存在争议。通过对守时激素褪黑素的研究，探讨了生物钟的位置。结果表明：(1)金鱼的眼睛有生物钟。(2)马苏鲑鱼和欧洲花斑石斑鱼松果体器官和欧洲花斑石斑鱼眼睛的生物钟均未发现阳性数据。(3)与其他鱼种相比，欧洲石斑鱼在明暗循环条件下眼部褪黑激素的变化呈现反转模式。(4)金鱼脑内褪黑激素受体与G-蛋白偶联。松果体褪黑激素下调了这些受体的日常节律。

1. Fish can learn demand feeding by operant conditioning. We kept red sea bream, goldfish and masu salmon by demand feeding method. Feeding and locomoter activity rhythms were simultaneously recorded. As the results, (1) these species easily learned demand feeding both individually or in groups. We could keep them longer only by this method. (2) Demand feeding showed better growth rate than the regular way of restricted feeding, especially in goldfish. (3) Circadian rhythms of both feeding and locomotor activities were confirmed under constant conditions, suggesting the existence of biological clock in these species.2. Multiple oscillators are assumed to be involved in the fish circadian system of locomotor, feeding and physiological functions. Correlation between oscillators and functions, however, are still controversial. Location of biological clock was investigated from the study of melatonin, the time-keeping hormone. As the results, (1) we found that goldfish eye has the biological clock. (2) There were no positive data on biological clock in the pineal organ of masu salmon and European sea bass, and the eye of European sea bass. (3) Melatonin profile in the eye of European sea bass under light-dark cycle displayd reversal pattern compared to the other fish species. (4) Melatonin receptors in the brain of goldfish coupled with G-proten. Daily rhythms of these receptors were down regulated by the pineal melatonin.