饲料中蛋白质含量及养殖密度对红鳍东方鲀幼鱼生长性能、氮排泄及相关生化指标的影响

Effects of dietary protein content and stocking density on growth performance, nitrogen excretion, and relevant biochemical parameters of juvenile Takifugu rubripes

中文关键词: 红鳍东方鲀  饲料蛋白  养殖密度  生长性能  氮排泄  生理生化指标

英文关键词: Tiger puffer  Dietary protein content  Stocking density  Growth performance  Nitrogen excretion  Biochemical indices

中文摘要:

      本实验以平均初始体重为15.60 g的红鳍东方鲀(Takifugu rubripes)幼鱼为研究对象，研究饲料中蛋白含量及养殖密度对红鳍东方鲀幼鱼生长性能、氮排泄及相关生理生化指标的影响。设计两因素三水平(2×3)实验，配制3种不同蛋白梯度(38.87%、45.55%和51.00%，干重)的等脂实验饲料，设置3个密度梯度为1.53 kg/m3 (0.196 m3体积的实验桶，每桶20尾鱼)、2.30 kg/m3(每桶30尾鱼)和3.06 kg/m3(每桶40尾鱼)。每组饲料设3个重复，养殖实验为期56 d，在室内流水系统内进行。结果显示，增重率在高、中蛋白组显著高于低蛋白组(P<0.05)，但当饲料蛋白含量一定时，养殖密度对增重率没有显著性影响。饲料蛋白含量和养殖密度对鱼体常规成分没有显著性影响。当饲料蛋白一定时，高密度组的血清总蛋白和胆固醇含量显著高于中密度组(P<0.05)。血清总蛋白含量在低蛋白组显著高于中蛋白组(P<0.05)。血清碱性磷酸酶含量在低蛋白组显著高于高蛋白组(P<0.05)。饲料蛋白含量和养殖密度对红鳍东方鲀幼鱼的生长、氨氮排泄没有显著性交互作用。静水投喂3 h后，氨氮排泄率在高密度组显著高于低密度组(P<0.05)。研究表明，45.55%饲料蛋白质含量已经能够满足红鳍东方鲀幼鱼正常生长的需求。饲料蛋白含量和养殖密度对红鳍东方鲀幼鱼的生长性能和氨氮排泄没有显著性交互作用。

英文摘要:

      The effects of protein content and stocking density on growth performance, nitrogen excretion, and related physiological and biochemical indexes of juvenile fish were studied using juvenile tiger puffers (Takifugu rubripes) with an average initial body weight of 15.60 g. A two-factor, three-level (2×3) design was used, with three different protein levels (38.87%, 45.55%, and 51.00% dry matter) and stocking densities of 1.53 kg/m3 (20 fish in a tank of 0.196 m3 volume), 2.30 kg/m3 (30 fish per tank), and 3.06 kg/m3 (40 fish per tank). The feeding trial was conducted in an indoor flow-through system. Each diet was fed to triplicate tanks for 8 weeks. The results showed that, at a certain stocking density, low dietary protein resulted in lower weight gain compared with the medium and high dietary protein levels (P<0.05). Neither dietary protein content nor stocking density significantly affected body proximate composition of experimental fish. At a certain dietary protein level, high stocking density increased total protein and total cholesterol contents in serum compared with medium stocking density (P<0.05). The total protein in serum was higher in the low-protein group than in the medium-protein group (P<0.05). The activity of alkaline phosphatase in serum was significantly higher in the low-protein group than in the high-protein group (P<0.05). No significant interaction was observed between the effects of dietary protein content and stocking density on growth performance and nitrogen excretion. Ammonia nitrogen excretion in the high-stocking-density group was higher than that in the low-stocking-density group at 3 hours after still-water feeding (P<0.05). Results of this study suggest that 45.55% dietary protein was sufficient to maintain normal growth in tiger puffers. Dietary protein content and stocking density had no significant interaction in the effects on growth performance and ammonia nitrogen excretion.