饲料脂肪水平对草鱼幼鱼生长和肝胰脏组织形态的影响

Effects of dietary lipid level on growth and hepatopancreas morphology of juvenile grass carp Ctenopharyngodon idella

为研究草鱼实用配方中脂肪的适宜含量,试验以草鱼实用配方配制基础饲料,在基础饲料中分别添加0%、1%、2%、3%、4%和5%的豆油,制成6种试验饲料。试验选取初始体质量(104.0±7.7)g的草鱼720尾,随机分为6组,每组6个重复,每个重复20尾鱼,养殖周期60 d。结果表明:(1)在饲料脂肪水平为5.72%~7.65%时,草鱼的增重率、特定生长率及蛋白质效率均显著高于未添加脂肪组(P<0.05),饲料系数呈现与之相反的趋势。(2)在饲料脂肪含量为6.48%时,草鱼增加单位体质量所消耗的饲料蛋白质质量显著低于其他各组(P<0.05)。(3)草鱼肝胰脏组织切片显微观察显示,6组草鱼肝胰脏细胞均排列整齐、大小均一、细胞膜分界明显,总体较健康,但有随饲料脂肪水平提高,细胞质中白色部分增多现象。本试验条件下,综合比较生长和饲料利用率,草鱼幼鱼饲料脂肪最适含量为6.3%~6.5%。

The purpose of this experiment was to study the appropriate content of lipid in the practical formula of grass carp.In this experiment,six experimental diets were formulated by adding 0%,1%,2%,3%,4%and 5%soybean oil into the basal diets,respectively.A total of 720 grass carps with an initial body weight of(104.0±7.7)g were allocated into 6 groups with 6 replicates of 20 grass carps each.The feeding lasted 8 weeks.The results showed that:(1)When dietary lipid level was 5.72%~7.65%,the weight gain rate,specific growth rate and protein efficiency rate of grass carps were significantly higher than the group without dietary lipid(P<0.05),and the feed conversion ratio showed an opposite trend.(2)When the dietary lipid content was 6.48%,the dietary protein weight consumed by grass carp to increase unit body weight was significantly lower than that consumed by other groups(P<0.05).(3)Microscopic observation of grass carp's hepatopancreas tissue sections showed that the six groups'hepatopancreas cells were orderly,uniform in size,and demarcated in the cell membrane.The hepatopancreas cells of the six groups were generally healthy,but the white part in the cytoplasm increased with the increase of dietary lipid level.The optimal dietary lipid content of juvenile grass carps was 6.3%~6.5%by comprehensive comparison of growth and feed utilization ratio.