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为研究在饲料中添加不同水平的溶菌酶制品对吉富罗非鱼(GIFT,Oreochromis niloticus)生长性能、免疫-抗氧化功能和血清抗菌性能的影响,选用平均体重为(11.35±0.08)g的吉富罗非鱼960尾,随机分为6组(每组4个重复,每个重复40尾),分别投喂基础饲料(对照组)和5种添加水平分别为18、36、54、72和90 mg/kg溶菌酶制品的试验饲料,养殖周期为60d。结果表明:(1)54 mg/kg溶菌酶添加组鱼的生长性能和饲料利用情况最优,增重率和蛋白质效率均显著高于对照组,饲料系数显著低于对照组(P<0.05);肝体比随溶菌酶添加水平的增加呈现下降趋势,90 mg/kg添加组显著低于对照组(P<0.05);脾脏指数在36和54mg/kg添加组显著低于对照组(P<0.05);全鱼粗蛋白和粗灰分含量在54 mg/kg添加组均呈现较高水平,显著高于对照组(P<0.05)。(2)溶菌酶添加水平对罗非鱼的免疫-抗氧化能力产生影响,54和72 mg/kg添加水平能显著提高鱼体血清和肝脏的超氧化物歧化酶、过氧化氢酶活性,降低丙二醛含量(P<0.05);肝脏溶菌酶活性在54和72 mg/kg添加组均显著高于对照组(P<0.05),而血清溶菌酶活性随溶菌酶添加水平的增加呈现下降趋势(L90组除外),显著低于对照组(P<0.05)。(3)血清抗菌试验显示,54和72 mg/kg溶菌酶添加组罗非鱼对大肠杆菌、金黄色葡萄球菌、嗜水气单胞菌和溶藻弧菌的抑制能力显著高于对照组(P<0.05),而对枯草芽孢杆菌的抵抗能力最低,比对照组分别低34.71%和42.21%(P<0.05)。结果表明,在本试验条件下,在吉富罗非鱼饲料中添加54 mg/kg溶菌酶制品可以改善其生长性能;当添加水平为54和72 mg/kg时,罗非鱼的免疫-抗氧化能力和血清抗菌性能均得到了显著提高。
In order to study the effect of different levels of lysozyme in feed on the growth performance, immune-anti-oxidation and antimicrobial activities of GIFT (Oreochromis niloticus), the average body weight of GIFT (11.35 ± 0.08) g Tilapia 960 were randomly divided into 6 groups (4 replicates in each group, 40 repeats each), and fed with basal diet (control group) and 5 added levels of 18, 36, 54, 72 and 90 mg / kg lysozyme product of the test feed, the breeding cycle of 60d. The results showed that: (1) The growth performance and feed utilization of 54 mg / kg lysozyme group were the best, the weight gain rate and protein efficiency were significantly higher than those of the control group, the feed coefficient was significantly lower than that of the control group (P <0.05) (P <0.05). The spleen index was significantly lower in the 36 and 54 mg / kg added groups than in the control group (P < 0.05). The crude protein and crude ash content in whole fish showed a higher level in the 54 mg / kg added group, which was significantly higher than that in the control group (P <0.05). (2) The level of lysozyme increased the immune-antioxidant capacity of tilapia. The levels of superoxide dismutase and catalase in serum and liver of fish decreased significantly at 54 and 72 mg / kg (P <0.05). Lysozyme activity of hepatic lysozyme at 54 and 72 mg / kg was significantly higher than that of the control group (P <0.05), while the activity of lysozyme in serum showed a decreasing trend with the increase of lysozyme (Except L90 group), which was significantly lower than that of the control group (P <0.05). (3) The results of serum antibacterial tests showed that the inhibitory effects of tilapia at 54 and 72 mg / kg lysozyme on Escherichia coli, Staphylococcus aureus, Aeromonas hydrophila and Vibrio alginolyticus were significantly higher than those in control group P <0.05), while the resistance to Bacillus subtilis was the lowest, 34.71% and 42.21% lower than the control group (P <0.05). The results showed that the addition of 54 mg / kg lysozyme to the feed improved the growth performance under the conditions of this experiment. When the supplementation levels were 54 and 72 mg / kg, the immune-antioxidant activity of tilapia Capabilities and serum antibacterial properties have been significantly improved.