Effects of Feeding Frequency and Feeding Level on Growth Performance and Physiological Indices of Juvenile Largemouth Bass Micropterus salmoides in Cyclic Water System

Abstract

目的：在室内循环水养殖系统中开展不同投喂频率和投喂量对大口黑鲈幼鱼(Micropterus salmoides)生长性能和生理指标影响的研究。方法：设置2个投喂水平(2%和4%的鱼体重量/日)和2个投喂频率(2次和3次/日)，共4个投喂处理组，每组设3个重复对照，在12个500 L容积的室内循环水养殖缸中开展养殖试验8周。结果：结果发现，增重率和特定生长率均以T1组最高，显著高于T2和T4组(P 0.05)。饲料系数的最高值和最低值分别出现在T4组和T1组(P 0.05)。T4组的肌肉水分含量相比于T1和T3组显著上升，但粗蛋白和粗脂肪含量则显著下降(P Objective: The present trial was conducted to study the effects of feeding frequency and feeding level treatment on growth and physiological indices of juvenile largemouth bass Micropterus salmoides (initial body weight 21.70 ± 0.56 g) in indoor cyclic water system. Method: Totally of 12 tanks were contained (500 L) with 2 feeding levels (2 and 4% body weight/day) and 2 feeding frequencies (2 and 3 times/day) were designed, altogether including 4 treatments with triplicate tanks respectively. 15 fish were selected randomly in each tank and the feeding trial lasted 8 weeks. Result: The results showed that the weight gain and specific growth rate of fish were higher in T1 gruop than those of fish in T2 and T4 groups (P < 0.05), and the data in T3 group were also higher than that of in T4 group (P < 0.05). The highest and lowest feed coefficient ratio was existed in T4 and T1 group, respectively (P < 0.05). The dorsal muscle moisture content in T4 group was significantly higher than those of fish in T1 and T3 groups, while the protein and lipid levels in T4 group showed decreasing trend (P < 0.05). The relatively higher activity of lipase in stomach were found in fish in T1 and T3 groups , and the highest activity of amylase was in T1 group (P < 0.05). The highest activity of trypsin in foregut was also observed in T1 group (P < 0.05). The T4 group showed the highest serum glutamic oxalacetic transaminase levels, and the data in T2 group was higher than those of in T1 and T3 groups (P < 0.05). The activities of superoxide dismutase and catalase in serum were relatively higher in T1 and T3 groups, on the contrary, the malondialdehyde levels were lower in these two treatments than those of fish in T2 and T4 groups (P < 0.05). Conclusion: The data generated from the current study suggested that feeding level at 4% BW per day with feeding frequency 2 times per day was optimal feeding strategy for juvenile M. salmoides.