本研究旨在研究乳源活性肽对罗非鱼生长性能和血清生化指标的影响。试验分为两部分，细胞离体培养试验（试验1）和饲养试验（试验2）。试验1：选用中性蛋白酶、木瓜蛋白酶、胰蛋白酶的不同组合（1号（中性蛋白酶和木瓜蛋白酶组合）、2号（胰蛋白酶和中性蛋白酶组合）、3号（胰蛋白酶））对干酪素进行水解得到3种产物，将这些产物对罗非鱼离体肝细胞进行细胞培养以确定最佳酶源。试验2：选取健康、体重相近（24.93±0.22） g的罗非鱼360尾，随机分为6组，每组3个重复，每个重复20尾，Ⅰ组（对照组）饲喂基础日粮，Ⅱ、Ⅲ、Ⅳ、Ⅴ和Ⅵ组（试验组）分别饲喂含有0.1％、0.2％、0.4％、0.8％和1.6％活性肽产品（最佳酶源水解产物）的试验日粮，试验期为8周。结果显示：（1）2号产品对罗非鱼离体肝细胞的增殖结果显著高于对照组和1、3号产品（P＜0.05）；（2）Ⅳ组罗非鱼的终末体重、增重率、特定生长率、饲料系数和蛋白质效率均显著高于对照和其他试验组（P＜0.05）；各组全鱼和背肌营养成分差异不显著（P>0.05）；试验组罗非鱼的血清补体活性和血清溶菌酶、高密度脂蛋白含量显著高于对照组（P＜0.05），且Ⅳ组显著高于Ⅱ、Ⅲ、Ⅴ和Ⅵ组（P＜005）；Ⅵ组血清总胆固醇含量显著高于对照组（P＜0.05），但与Ⅱ、Ⅲ、Ⅳ和Ⅴ组差异不显著（P>0.05）。由结果可知，在本试验条件下，2号产品水解干酪素所得活性肽以0.4%的添加量最为理想。

This experiment was conducted to investigate the effects of milk origin bioactive peptides on growth performance and serum biochemical parameters of tilapia ( Oreochromis aureus×O.niloticus). The study contained two experiments, experiment 1 was cell cultured  in vitro  experiment, and experiment 2 was feeding experiment. Experiment 1: In order to estimate the best enzyme source, three casein hydrolysate samples were prepared by different enzyme combinations (production 1: neutral protease and pawpaw protease combination, production 2: trypsin and neutral protease combination, production 3: trypsin), and used in liver cells cultured  in vitro experiment. Experiment 2: three hundred and sixty tilapia with an average body weight of (24.93±0.22) g were randomly allocated into 6 groups (groupⅠ was control group, group Ⅱ,Ⅲ,Ⅳ,Ⅴ and Ⅵ were test group) with 3 replicates in each group and each replicate contained 20 fish. Group Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ and Ⅵwere fed diet with 0, 0.1％, 0.2％, 0.4％, 0.8％ and 1.6％ milk origin bioactive peptides (hydrolysate of the best enzyme source), respectively. The experiment lasted for 8 weeks. The results showed that: (1) the effect of liver cells cultured  in vitro  of production 2 was significantly higher than that of control and production 1, 3 (P＜0.05); (2) the final weight, weigh gain ratio, specific growth ratio, feed conversion ratio, protein efficiency ratio of tilapia in group Ⅳ were significantly higher than that in control and the other test groups (P＜0.05); there were no significant differences in nutrient components of whole fish body and back muscle among six groups (P>0.05); the concentrations of compliment, lysozyme and high density lipoprotein in serum of tilapia test group were significantly higher than that in control group (P＜0.05), and that in group Ⅳ were significantly higher than that in group Ⅱ, Ⅲ, Ⅴand Ⅵ (P＜0.05); the concentrations of cholesterol in serum of tilapia in group Ⅵ was significantly higher than that in control group (P＜0.05), but no significant differences were found among the test groups. In conclusion, our study indicated that the most suitable dose of milk origin bioactive peptides in diet of tilapia was 0.4%.