饲料中脂肪水平对团头鲂幼鱼生长性能、血清生化指标及黏蛋白基因表达的影响

Dietary Lipid Level Affects Growth Performance,Serum Biochemical Indexes and Mucin Gene Expression of Juvenile Blunt Snout Bream(Megalobrama amblycephala)

本试验旨在研究饲料中不同脂肪水平对团头鲂幼鱼生长性能、血清生化指标及黏蛋白基因表达的影响。试验选取540尾初始体重为(10.0±0.5)g的团头鲂幼鱼,随机分为6组,每组3个重复,每个重复30尾鱼,分别投喂脂肪水平为2.29%、4.29%、6.29%、8.29%、10.29%和12.29%的等氮等能试验饲料。饲养8周后检测鱼体生长指标、血清生化指标和表皮、肠道中黏蛋白基因的表达。结果表明:1)6.29%和8.29%组的增重率(WGR)显著高于其他组(P<0.05),饲料系数(FCR)显著低于其他组(P<0.05)。2)12.29%组血清皮质醇含量及谷丙转氨酶(ALT)和谷草转氨酶(AST)活性最高,显著高于2.29%、4.29%、6.29%和8.29%组(P<0.05),但与10.29%组没有显著差异(P>0.05)。3)8.29%组鱼体肝脏中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和还原型谷胱甘肽(GSH)含量显著高于2.29%组(P<0.05);而谷胱甘肽还原酶(GR)活性在6.29%组最高,除8.29%组外,显著高于其他各组(P<0.05);丙二醛(MDA)含量在6.29%组最低,显著低于2.29%和12.29%组(P<0.05)。4)12.9%组肠道黏蛋白2(Muc2)基因表达量显著高于其他各组(P<0.05),8.29%组表皮黏蛋白5b(Muc5b)基因表达量与12.29%组没有显著性差异(P>0.05),但显著高于其他各组(P<0.05)。5)病原菌感染试验表明,2.29%和12.29%组死亡率较高,6.29%和8.29%组死亡率较低,且显著低于其他各组(P<0.05)。综上,在本试验条件下,饲料脂肪水平在6.29%~8.29%时,团头鲂幼鱼生长性能、抗病力和表皮黏蛋白Muc5b基因表达量最高。

This study was aimed to investigate the effects of dietary lipid level on growth performance, serum biochemical indexes and mucin gene expression of juvenile blunt snout bream （ Megalobrama amblycephala ）. A total of 540 juvenile blunt snout breams with an initial average body weight of （10.0±0.5） g were randomly divided into 6 groups with 3 replicates in each group and 30 fish in each replicate and fed isonitrogenous and isoenergetic diets containing 2.29%, 4.29%, 6.29%, 8.29%, 10.29% and 12.29% lipid, respectively. After 8-week feeding trail, the growth, serum biochemical indexes and mucin gene expression in skin and intestine were detected. The results showed as follows： 1） the weight gain rate （WGR） in 6.29% and 8.29% groups was significantly higher than that in other groups （ P 〈0.05）, while the feed conversion ratio （FCR） was significantly lower than that of other groups （ P 〈0.05）. 2） Cortisol content and alanine transaminase （ALT） and aspartate transaminase （AST） activities in serum in 12.29% group were the highest, and significantly higher than those in 2.29%, 4.29% , 6.29% and 8.29% groups （ P 〈0.05）, but not significant in 10.29% group （ P 〉0.05）. 3） The activities of superoxide dismutase （SOD）, catalase （CAT） and GSH content in liver in 8.29% group were significantly higher than those in 2.29% group （ P 〈0.05）; glutathione reductase （GR） activity in 6.29% was the highest, and significantly higher than that in other groups except for 8.29% group （ P 〈0.05）; malonaldehyde （MDA） content in 6.29% group was the lowest, and significantly lower than that in 2.29% and 12.29% groups （ P 〈 0.05 ）. 4） The intestinal mucin 2 （ Muc2 ） gene expression level in 12.29% group was significantly higher than that in other groups （ P 〈0.05）; there was no significant difference in the skin mucin 5b （ Muc5b ） gene expression level between 8.29% and 12.29% groups（ P 〉0.05）, but significantly higher than other groups （ P 〈 0.05 ）. 5） After challenged, the death ratio in 2.29% and 12.29% groups was the highest and that in 6.29% and 8.29% groups was the lowest, and was significantly lower than that in other groups （ P 〈0.05）. In conclusion, under this experiment conditions, when the dietary lipid levels are 6.29% to 8.29% , juvenile blunt snout bream have the best growth performance, disease-resistant ability, and skin Muc5b gene expression level.