酶解羊毛粉替代鱼粉并添加胆汁酸对大口黑鲈幼鱼生长性能及脂质代谢的影响

Effects of Enzymatic Wool Meal Replacing Fish Meal and Adding Bile Acid on Growth Performance and Lipid Metabolism of Juvenile Largemouth Bass(Micropterus salmoides)

本试验旨在研究酶解羊毛粉(EWM)替代鱼粉并添加胆汁酸(BA)对大口黑鲈幼鱼生长性能及脂质代谢的影响。试验选择180尾大小均匀、初始体重为(10.00±0.02)g的大口黑鲈幼鱼,随机分为3组,每组3个重复,每个重复20尾鱼。对照组(CON组)饲喂以鱼粉和豆粕为蛋白质源的基础饲料,酶解羊毛粉组(EWM组)饲喂在基础饲料中用酶解羊毛粉替代25%鱼粉的试验饲料,酶解羊毛粉+胆汁酸组(EWM+BA组)饲喂在基础饲料中用酶解羊毛粉替代25%鱼粉并添加0.6 g/kg胆汁酸的试验饲料。试验期56 d。结果表明:1)EWM+BA组的末重(FBW)、增重率(WGR)、特定增长率(SGR)均显著高于CON组和EWM组(P<0.05)。2)EWM组的血清甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)含量和肝脏中总胆固醇(TC)、总胆汁酸(TBA)含量均显著高于CON组(P<0.05)。EWM+BA组的肝脏TG、TC、TBA含量和血清TBA含量均显著低于EWM组(P<0.05)。3)EWM组的肝脏乙酰辅酶A羧化酶1(ACC1)、脂肪酸结合蛋白(FABP)、硬脂酰辅酶A去饱和酶(SCD)、甘油三酯脂肪酶(ATGL)的mRNA相对表达水平显著高于CON组(P<0.05)。EWM+BA组的肝脏脂肪酸合成酶(FAS)、ACC1、SCD、固醇调节元件结合蛋白1(SREBP1)、过氧化物酶体增殖激活受体α(PPARα)、脂蛋白脂酶(LPL)和瘦素(LEP)的mRNA相对表达水平显著高于CON组和EWM组(P<0.05)。4)EWM组和EWM+BA组的肝脏法尼醇X受体(FXR)、类视黄醇X受体(RXR)的mRNA相对表达水平显著低于CON组(P<0.05)。EWM组的肝脏小异二聚体伴侣(SHP)的mRNA相对表达水平显著高于CON组和EWM+BA组(P<0.05)。EWM+BA组的肝脏胆固醇7α-羟化酶(CYP7A1)和成纤维细胞生长因子19(FGF19)的mRNA相对表达水平显著高于CON组和EWM组(P<0.05)。由此可见,酶解羊毛粉替代部分鱼粉并添加外源胆汁酸可缓解酶解羊毛粉对大口黑鲈的生长性能、脂质代谢和胆固醇代谢产生的不利影响。

The aim of this experiment was to investigate the effects of enzymatic wool meal(EWM)replacing fish meal and adding bile acid(BA)on growth performance and lipid metabolism of juvenile largemouth bass(Micropterus salmoides).A total of 180 uniform size largemouth bass with initial body weight of(10.00±0.02)g were randomly divided into 3 groups with 3 replicates per group and 20 fish per replicate.The control group(CON group)was fed a basal diet containing fish meal and soybean meal as protein sources,the enzymatic wool meal group(EWM group)was fed the experimental diet which using enzymatic hydrolyzed wool meal instead of 25%fish meal in basal diet,and the enzymatic wool meal+bile acid group(EWM+BA group)was fed the experimental diet which using enzymatic hydrolyzed wool meal instead of 25%fish meal and adding bile acid in basal diet.The experiment lasted for 56 days.The results showed as follows:1)the final body weight(FBW),weight gain rate(WGR)and specific growth rate(SGR)of EWM+BA group were significantly higher than those of CON group and EWM group(P<0.05).2)The contents of triglycerides(TG),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)in serum and contents of total cholesterol(TC)and total bile acid(TBA)in liver of EWM group were significantly higher than those of CON group(P<0.05).The contents of TG,TC and TBA in liver and serum TBA content of EWM+BA group were significantly lower than those of EWM group(P<0.05).3)The mRNA relative expression levels of acetyl CoA carboxylase 1(ACC1),fatty acid-binding protein(FABP),stearoyl-CoA desaturase(SCD)and adipose triglyceride lipase(ATGL)in liver of EWM group were significantly higher than those of CON group(P<0.05).The mRNA relative expression levels of fatty acid synthase(FAS),ACC1,SCD,sterol regulatory element binding protein 1(SREBP1),peroxisome proliferator-activated receptor-alpha(PPARα),lipoprotein lipase(LPL)and leptin(LEP)in liver of EWM+BA group were significantly higher than those of CON group and EWM group(P<0.05).4)The mRNA relative expression levels of farnesol X receptor(FXR)and retinoid X receptor(RXR)in liver of EWM group and EWM+BA group were significantly lower than those of CON group(P<0.05).The liver small heterodimer partners(SHP)mRNA relative expression level of EWM group was significantly higher than that of CON group and EWM+BA group(P<0.05).The mRNA relative expression levels of cholesterol 7 alpha-hydroxylase(CYP7A1)and fibroblast growth factor 19(FGF19)in liver of EWM+BA group were significantly lower than those of CON group and EWM group(P<0.05).In conclusion,the enzymatic wool meal replacing some fish meal and adding exogenous bile acid can mitigate the adverse effects of enzymatic wool meal on growth performance,lipid metabolism and cholesterol metabolism in largemouth bass.