外源脂肪酶对花鲈生长性能、体组成、血清生化指标、消化酶活性及营养物质表观消化率的影响

本试验旨在研究低蛋白质高脂肪饲料中添加外源脂肪酶对花鲈生长性能、体组成、血清生化指标、消化酶活性及营养物质表观消化率的影响。试验选取初始体重为(6.26±0.02)g的花鲈600尾,随机分成6组,每组4个重复,每个重复25尾。正对照组(G+组)饲喂高蛋白质低脂肪(41.76%粗蛋白质和8.34%粗脂肪)的正常饲料,对照组(G0组)饲喂低蛋白质高脂肪(37.64%粗蛋白质和11.15%粗脂肪)饲料,试验组(G100、G200、G400和G800组)分别饲喂在低蛋白质高脂肪饲料中添加100、200、400和800 mg/kg脂肪酶的试验饲料。试验期为8周。结果表明:1)与G+组相比,G0组花鲈的终末体重、增重率、摄食量和肝体比均升高(P0.05),脏体比和脂体比显著升高(P0.05),血清总抗氧化能力显著下降(P0.05),干物质、粗蛋白质、粗脂肪和总能的表观消化率下降(P0.05),脂肪酸C16∶1-n9和C18∶3-n3的表观消化率显著升高(P0.05)。2)与G0组相比,试验组的终末体重和增重率降低;其中G800组终末体重、增重率显著降低(P0.05),饲料系数显著增加(P0.05),存活率显著下降(P0.05),脏体比和脂体比降低(P0.05),中肠脂肪酶和肝脏蛋白酶活性降低(P0.05),血清胆固醇、高密度脂蛋白胆固醇、甘油三酯含量下降(P0.05);G200组血清谷丙转氨酶活性和丙二醛含量显著下降(P0.05)。由此可见,饲料脂肪可以节约部分蛋白质,低蛋白质高脂肪饲料对花鲈生长性能、体组成和消化酶活性等没有显著影响,但显著提高脏体比和脂体比。在低蛋白质高脂肪饲料中添加脂肪酶,花鲈生长性能有所降低,对消化酶活性及血清生化指标无显著影响,粗脂肪和部分脂肪酸表观消化率下降,但脏体比和脂体比一定程度上降低,机体抗氧化能力增强。

Effects of Exogenous Lipase on Growth Performance,Body Composition,Serum Biochemical Indices,Digestive Enzyme Activities and Nutrient Apparent Digestibilities of Lateolabrax japonicas

This study was conducted to investigate the effect of exogenous lipase supplementation in low-pro-tein and high-fat diets on growth performance, body composition, serum biochemical indices, digestive en-zyme activities and nutrient apparent digestibility of Lateolabrax japonicus.A total of 600 Lateolabrax japoni-cas with the average body weight of (6.26±0.02) g were randomly allocated into 6 groups with 4 replicates per group and 25 fish per replicate.Fish in the positive control group ( G+group) were fed a normal diet with high-protein and low-lipid (41.76% crude protein and 8.34% ether extract), fish in the control group ( G0 group) were fed a low-protein and high-fat diet (37.64% crude protein and 11.15% ether extract), and others in the experimental groups ( G100, G200, G400 and G800 groups) were fed the low-protein and high-fat diet supplemented with 100, 200, 400 and 800 mg/kg exogenous lipase, respectively.The experiment lasted for 8 weeks.The results showed as follows: 1) compared with the G+group, the final body weight, weight gain rate, feed intake and hepatopanceas index of G0 group were increased ( P>0.05), the viscerosomatic index and intraperitioneal fat index of G0 group were significantly increased (P<0.05), the serum total antioxidant capacity of G0 group was significantly decreased ( P<0.05) , the apparent digestibilities of dry matter, crude protein, ether extract and gross energy of G0 group were significantly decreased ( P<0.05) , the apparent di-gestibilities of C16:1-n9 and C18:3-n3 fatty acids of G0 group were significantly increased ( P<0.05 ) .2 ) Compared with the G0 group, the final body weight and weight gain rate of experimental groups were de-creased (P>0.05); the final body weight and weight gain rate of G800 group were significantly decreased (P<0.05), the feed conversion rate of G800 group was significantly increased (P<0.05), the viscerosomatic index and intraperitioneal fat index of G800 group were decreased ( P>0.05) , the activities of lipase in mid-in-testine and protease in liver of G800 group were decreased ( P>0.05) , the contents of cholesterol, high density lipoprotein cholesterol and triglyceride in serum of G800 group were decreased ( P>0.05);the glutamic pyru-vic transaminase activity and malondialdehyde content in serum of G200 group were significantly decreased ( P<0.05) .In conclusion, dietary lipid can partially spare protein, the low-protein and high-lipid diet signifi-cantly increased viscerosomatic index and intraperitioneal fat index, but has no significant effect on growth per-formance, body composition and digestive enzyme activity of Lateolabrax japonicas.Meanwhile, exogenous lipase supplementation in low-protein and high-fat diets made growth performance of Lateolabrax japonicas de-clined, had no obvious effects on digestive enzyme activity and serum biochemical indices, the digestibilities of ether extract and partial fatty acids are decreased, but the viscerosomatic index and intraperitioneal fat index are decreased to a certain extent, and improve the antioxidant capacity.