不同开口饵料对半刺厚唇鱼仔鱼摄食、生长与成活的影响

Effects of Different Weaning Diets on Feeding, Growth and Survival of Larval Acrossocheilius hemispinus

在水温23~25℃下,将刚开口摄食的5日龄半刺厚唇鱼Acrossocheilius hemispinus仔鱼饲养在60cm×50cm×50cm玻璃缸中,密度为300尾/缸,投喂淡水轮虫(10ind./mL)、水蚯蚓浆(过150μm筛网)、蛋黄(250μm纱布揉洗)、鱼苗开口料和虾奶粉,以筛选半刺厚唇鱼仔鱼的适宜开口饵料。22d的饲养结果表明:摄食不同饵料的半刺厚唇鱼仔鱼的初次摄食率、生长速率和成活率差异显著(P<0.05),其中淡水轮虫组初次摄食率最高(98.89%),生长速率最快(日增全长0.43mm),存活率97.33%;水蚯蚓浆组初次摄食率亦达到95.56%,平均日增全长为0.36mm,存活率为85.44%;蛋黄组虽然初次摄食率(90.00%)较高,但其生长速率(日增全长0.13mm)和成活率(57.00%)均较低,显著低于淡水轮虫组和水蚯蚓浆组(P<0.05);而开口饲料组和虾奶粉组的初次摄食率和成活率均显著低于其他3组(P<0.05)。总之,淡水轮虫是半刺厚唇鱼仔鱼的最适开口饵料;水蚯蚓浆为适宜开口饵料,缺乏淡水轮虫时可用其替代作为半刺厚唇鱼仔鱼的开口饵料。

Five-day-old Acrossocheilius hemispinus larvae were red in a glass tank of 60 cm×50 cm×50 cm at a density of 300 larvae per tank and fed freshwater rotifers(10 ind./mL),earthworm pulp(over 150μm screen),yolk(250μm gauze rubbing and washing),fry starter and shrimp milk powder at water temperature of 23~25℃for 22 days to screen suitable weaning food for the larvae.The larvae fed different weaning diets had significantly different initial feeding rate,growth rate and survival rate(P<0.05).There were the maximal initial feeding rate(98.89%),best growth rate(daily average increase in total length of 0.43 mm)and the highest survival rate of 97.33%in the larvae in freshwater rotifers group,and initial feeding rate of 95.56%,daily average increase in total length of 0.36 mm and survival rate of 85.44%in the water earthworm(pulp)group.There were poor growth rate(daily average increase in total length of only 0.13 mm)and lower survival rate(57.00%)in the egg yolk group,significantly lower than those in freshwater rotifers and aquatic earthworms(P<0.05),although there was higher initial feeding rate(90.00%)in the egg yolk group.The significantly lower initial feeding rate and survival rate were observed in the shrimp milk powder group than those in the other three groups(P<0.05).In conclusion,freshwater rotifers are the most suitable weaning food for A.hemispinus larvae.Water earthworm(pulp)is a suitable substitute of weaning diet for A.hemispinus larvae in the absence of freshwater rotifers.