延迟投喂对褐菖仔鱼存活和生长的影响

为研究褐菖仔鱼在饥饿条件下的存活与生长, 对其仔鱼初次摄食率和饥饿不可逆点以及延迟投喂下仔鱼的存活及生长特征进行研究. 结果表明: 16~18℃下, 仔鱼产出当日开口摄食, 4日龄仔鱼初次摄食率最高, 达(93.33±9.43)％, 饥饿不可逆点为7.2日龄; 投喂组仔鱼卵黄囊消耗较饥饿组快, 前者卵黄囊于5日龄基本耗尽, 后者维持到8日龄; 延迟投喂1~5d各组, 其10日龄仔鱼存活率在70%以上, 显著高于延迟投喂6~9d各组(P＜0.05); 初产仔鱼平均全长为(4.15±0.10) mm, 饥饿3d内, 全长平均日增长量为8.3×10-2 mm?d-1, 第4天后出现负增长; 延迟投喂0~3d各组的20日龄仔鱼全长及特殊增长率均无显著差异(P＞0.05), 但延迟4d后各投喂组, 各指标均出现显著下降(P＜0.05). 因此认为, 褐菖仔鱼最佳投喂时间为4日龄, 对其以后的生长、存活最有利.

. �C;Effects of Delayed Feeding on Survival and Growth of �B;Sebastiscus marmoratus larva

To study the survival and growth of Sebastiscus marmoratus larvae under conditions of starvation, the initial feeding rate of larval, the starvation of point of no return (PNR) and survival and growth characteristics of larvae with delayed feeding are observed. The results show that the larvae of Sebastiscus marmoratus begin taking food in the day of birth under water temperature of 16~18℃, the initial food-taking rate of larvae reaches the highest of (93.33±9.43)% at age of 4-day, and the point of no return is found to be 7.2-day after birth. The consumption of yolk sac is faster in feeding group than in hungry group, and the former yolk sac is exhausted basically at 5-day age, while the latter is extended to 8-day age. The average length of primiparous larvae is (4.15±0.10) mm. The total length of the average daily growth of larvae is 8.3×10-2 mm?d-1 in hunger 3 d and shows negative growth after 4 d. The total length, the average daily growth and specific growth rate of larvae in each group of 20 day-old show no significant difference (P>0.05) under delayed feeding for 0-3 d, but above indices of larvae in each group of 20 day-old are significantly decreased (P<0.05) under delayed feeding with 4 d after. The comprehensive analysis indicate that the optimal feeding time of Sebastiscus marmoratus larvae should be 4 days after birth