生物絮团对团头鲂(Megalobrama amblycephala)生长、消化酶和免疫相关酶活性的影响

Effects of Bioflocs on Growth Performance, Digestive Enzyme and Immunity Enzyme Activities in Juvenile Blunt Snout Bream (Megalobrama amblycephala)

中文关键词: 生物絮团  团头鲂  碳氮比(C/N)  消化酶  免疫酶

英文关键词: Biofloc  Megalobrama amblycephala  C:N ratio  Digestive enzyme  Immunity enzyme

中文摘要:

      为了研究零换水条件下团头鲂(Megalobrama amblycephala)养殖水体生物絮团形成所需的适合的碳氮比(C/N)，以及不同C/N形成的生物絮团对团头鲂生长、消化酶活性和非特异性免疫力的影响，本实验设计4个不同C/N实验组，包括投喂基础饲料(C/N=8∶1)的对照组，在基础饲料上添加葡萄糖的处理组，其中将处理组的C/N分别调整为12∶1 (C/N12)、16∶1 (C/N16)和20∶1 (C/N20)。结果显示，C/N16和C/N20处理组中团头鲂的增重率和特定生长率显著高于对照组(P<0.05)，而饲料系数显著低于对照组(P<0.05)；C/N16和C/N20处理组中团头鲂肠道的蛋白酶活性和淀粉酶活性显著高于对照组(P<0.05)；而各实验组中团头鲂肠道的脂肪酶活性没有显著性差异；C/N16和C/N20处理组中团头鲂肝脏超氧化物歧化酶、碱性磷酸酶和溶菌酶活性显著高于对照组(P<0.05)。研究表明，生物絮团技术应用于团头鲂养殖适宜的C/N应不低于16，该条件下形成的生物絮团能有效提高团头鲂生长、消化酶和免疫相关酶活性。

英文摘要:

      Bioflocs are heterogeneous mixtures of microorganisms and organic particles that regulate the accumulation of ammonia and nitrite and serve as a supplemental food source for fish. A 56-day feeding experiment was conducted to investigate the effects of bioflocs on the growth performance, the activity of digestive enzymes, and non-specific immunity of (37.75±0.62) g juvenile Megalobrama amblycephala in zero-water exchange culture tanks. Glucose at different concentrations were used as the carbon source in the water. A series of C/N ratios including 8 (CN8), 12 (CN12), 16 (CN16) and 20 (CN20) were presented in biofloc-based tanks under zero-water exchange condition. Three biofloc treatments and one control treatment were applied to a triplicate. It was found that at the end of the experiment the survival rates of all the groups were >90% without significant differences between groups. The growth performance indicators such as the final weight, the weight gain and the specific growth rate were significantly higher (P<0.05) in the CN16 and CN20 groups than in the control group. Moreover, the biofloc treatments significantly enhanced activities of protease and amylase in the intestine of fish (P<0.05), but these treatments did not alter the body composition. We also observed marked differences in the activities of superoxide dismutase, alkaline phosphatase and lysozyme of the fish liver between the biofloc treatment groups and the control group. These results suggested that bioflocs in the CN16 and CN20 groups could improve the growth performance and feed utilization of cultured juvenile M. amblycephala, probably through the enhanced intestinal digestive enzyme activity and the subsequent feed digestion and utilization.