投饲频率和饵料种类对中华绒螯蟹幼蟹生长及能量收支的影响

在水温18～22℃下,研究了不同投饲频率(1次/d、2次/d和3次/d)和饵料种类(鲜杂鱼和配合饲料)对中华绒螯蟹Eriocheir sinensis幼蟹(4.96 g±0.08 g)生长及能量收支的影响,试验共进行48 d。结果表明:随着投饲频率的增加,中华绒螯蟹幼蟹的增重率、特定生长率逐渐增加(P>0.05);配合饲料组幼蟹的成活率、蜕壳率均高于鲜杂鱼组;投饲频率相同时,配合饲料组幼蟹的摄食率均显著高于鲜杂鱼组(P<0.05);各组饲料转化效率随着投饲频率的增加逐渐降低;随着投饲频率的增加,各组幼蟹的体成分无显著性差异(P>0.05),饵料种类和投饲频率对幼蟹体成分无交互作用(P>0.05);随着投饲频率的增加,鲜杂鱼组幼蟹的生长能占摄食能的比例逐渐降低,代谢能所占比例逐渐增加,而配合饲料组幼蟹则与其呈相反态势;各组幼蟹的排粪能占摄食能的比例随投饲频率的增加而下降,配合饲料组排粪能所占比例显著高于鲜杂鱼组(P<0.05)。在本试验条件下,中华绒螯蟹幼蟹的适宜投饲频率为2次/d。

Effects of feeding frequency and food type on growth and energy budget of juvenile Chinese mitten crab Eriocheir sinensis

A 48-day feeding experiment was carried out to investigate the effects of feeding frequency（ once a day, twice a day, and three times a day） and food types （formulated diets and fresh trash fish） on growth and energy budget of juvenile Chinese mitten crab Eriocheir sinensis with initial body weight of（4.96±0.08 ） g at water tempera- ture of 18-22 ℃. The results showed that the body weight gain and specific growth rate of the crab were loud to be increased gradually with the increasing feeding frequency, without significant differences （ P 〉 0.05 ）. There were significantly higher survival and molting rates in the juveniles fed the formulated diets than those in the animals fed the fresh trash fish. Within the same feeding frequency,however, the crab fed the formulated diets had significantly higher food intake than the crab fed the fresh trash fish （P〈0. 05）, and the food conversion efficiencies were de- creased gradually in the different groups with increasing feeding frequency. The body composition of the crab was shown no significant differences in different groups with increasing feeding frequency（ P〉0.05 ）, and there was no interaction between the diet types and feeding frequency on body composition of the crab（P〉0.05）. The crab fed the fresh trash fish showed gradual decrease in energy allocated to growth, and high metabolic energy with the in- creasing feeding frequency. However,the crab fed the formulated diets showed an opposite case. The partitions of fecal energy in growth energy were decreased gradually with the increasing feeding frequency in different groups. There was significantly higher fecal energy in the crab fed the formulated diets than that in the crab fed the fresh trash fish（P〈0.05）. In the experiment,the optimal feeding frequency was found at feeding frequency of twice a day.