投喂不同饵料对长薄鳅生长的影响

在水温18.6～21.6℃条件下,将初始体质量为(3.91±0.22) g的长薄鳅幼鱼随机分为5组,每组3个重复,每个重复10尾鱼,饲养在圆形玻纤缸(直径1 m、高0.8 m)中,分别投喂刀额新对虾、鳙鱼、配合饲料(粗蛋白≥46.0%)、虾+饲料、鱼+饲料5种饵料,以筛选适宜于长薄鳅幼鱼的适宜饵料投喂模式。75 d的饲养结果表明,不同投喂模式对长薄鳅的存活率无显著性影响(P>0.05),而对长薄鳅的生长影响显著(P<0.05)。试验结果表明,虾组、鱼组、饲料组、鱼+饲料组的长薄鳅最终体质量无显著性差异(P>0.05),但虾+饲料组最终体质量和体质量特定生长率显著高于其他4组(P<0.05),依次为虾+饲料组>饲料组>虾组>鱼组、鱼+饲料组。5个试验组鱼的体长特定生长率无显著性差异(P>0.05),依次为虾+饲料组>虾组>饲料组、鱼+饲料组>鱼组。试验结束时,各试验组鱼的生长离散均有所升高,生长离散变化依次为鱼组>鱼+饲料组>饲料组>虾组>虾+饲料组。各试验组长薄鳅的的摄食率差异显著(P<0.05),摄食率依次为鱼组>虾组>鱼+饲料组>虾+饲料组>饲料组;虾组和鱼组的饵料系数无显著性差异(P>0.05),但显著高于其他3组(P<0.05),其他3组间无显著性差异(P>0.05)。不同投喂模式下长薄鳅幼鱼的生长系数b值均小于3,呈负异速生长,但虾+饲料组的长薄鳅幼鱼生长系数b值最大。试验过程中各组鱼的肥满度均下降。研究结果显示,在本试验的不同饵料投喂模式中,投喂虾+饲料更利于长薄鳅的摄食和生长。

Effect of Different Diets on Growth Performance of Elongate Loach Leptobotia elongata

Juvenile elongate loach Leptobotia elongata with body weight of (3.91±0.22) g were reared in a circular glass fiber cylinder with diameter of 1 m and height of 0.8 m and fed 5 diets including shrimp Metapenaeus ensis ,bighead carp Aristichthys nobilis ,formulated feed (crude protein ≥ 46.0%),shrimp + formulated feed,and fish + formulated feed at a water temperature from 18.6 ℃ to 21.6 ℃ for 75 d with 3 replicates in order to evaluate the effects of different diets on growth performance of elongate loach juveniles. The results showed that there was no significant effect of diet types on the survival rate ( P > 0.05 ),with significant effect of diet types on the growth of the juveniles. There was significantly higher final body weight in the juveniles fed the diet of shrimp + formulated feed than that in the juveniles fed the other 4 diets ( P <0.05),as the descending order of final body weight being described as the juveniles fed the diet of shrimp + formulated feed>juveniles fed the formulated feed>juveniles fed the shrimp>juveniles fed the fish,and juveniles fed the diet of the fish+ formulated feed,though without significant difference in the final body weight in the other 4 groups. The juveniles fed the shrimp + formulated feed diet had significantly higher specific growth rate in body weight than the animals fed the other 4 diets did ( P <0.05),with the order as shrimp + feed group > feed group > shrimp group > fish group and fish + feed group,without significant differences in body length growth rate among the 5 groups ( P >0.05). The elevated growth discrepancies were observed among the groups at the end of the experiment,with the order as fish group> fish + feed group> feed group> shrimp group> shrimp + feed group. There was a significant difference in food intake among the experimental groups ( P <0.05),with the order as fish group> shrimp group> fish + feed group> shrimp + feed group> feed group. There was no significant difference in food conversion efficient between the juveniles fed the shrimp and the juveniles fed the fish ( P > 0.05),significantly higher than that in other three groups ( P <0.05). The juveniles among the experimental groups all had allometric growth factor b values of less than 3,showing negative allometric growth,with the maximal b value in the juveniles fed the diet of the shrimp + feed,and low condition factors during the test. The findings suggest that the combination of shrimp and formulated feed is more conducive to the feeding and growth of elongate loach in the different feeding modes.