黄霉素对尼罗罗非鱼生长、微生态和免疫特性的影响

Effects of flavomycin on growth performance,microbial ecology and immunity of Nile tilapia

为了对黄霉素在水产养殖中的应用提供依据,将180尾平均质量3.90 g左右的健康尼罗罗非鱼随机分为2组,每组3个重复,每重复30尾,一组饲喂基础日粮(对照组),另一组在基础日粮中添加4 mg/kg黄霉素,以研究黄霉素对尼罗罗非鱼生长、微生态和免疫特性的影响。结果表明,与对照组相比,饲料中添加黄霉素使尼罗罗非鱼日增质量和特定生长率分别提高了11.11%(P<0.05)和5.38%(P<0.05),蛋白质效率和存活率均有提高的趋势,饲料系数有降低的趋势,但差异均不显著(P>0.05);黄霉素使尼罗罗非鱼肠道细菌数量显著降低(P<0.05),对皮肤和鳃细菌数量以及皮肤、鳃和肠道的菌群组成均无显著影响(P>0.05);黄霉素显著提高了白细胞吞噬百分率(P<0.05),对白细胞吞噬指数、血清和体表粘液的溶菌酶活性、红细胞C3b受体花环百分率和T淋巴细胞活性E花环百分率均无显著影响(P>0.05)。说明黄霉素提高了尼罗罗非鱼的生长性能和机体免疫力。

A total of 180 Nile tilapia at an average initial body weight of 3.9 g were randomly allocated to 2 treatments ,each of which had three replicates of 30 fish/tank and was used to investigate the effects of flavomycin on growth performance,intestinal microflora and immunity by providing applicable evidences of flavomycin in aquaculture. The fish received the same basal diet and flavomycin was added to the basal diet at 4 mg/kg. Compared with the control, supplementation with flavomycin significantly increased average daily weight gain and specific growth rate by 11.11% （P〈0.05） and 5.38% （P〈0.05） ,respectively. Supplementation with flavomycin had a tendency to improve feed conversion ratio,protein efficiency ratio and survivor ratio （P〉0.05）. Addition of flavomycin significantly reduced the total intestinal aerobic bacterial counts. However,the total aerobic bacterial counts of the skin and gill as well as the composition of microflora from the skin,gill and intestine were not affected by flavomycin. Addition of flavomycin improved the phagocytic activity of leukocytes of Nile tilapia （P〈0.05） and had no significant effect on phagocytic index of leukocytes,lysozyme activity,percentage of erythrocyte C3b receptor and erythocyte active rosette of T lymphocyte of Nile tilapia. Supplementation with flavomycin promoted growth performances and immunity in Nile tilapia.