包膜蛋氨酸对凡纳滨对虾幼虾生长性能、饲料利用和代谢的影响

Effects of Coated Methionine on Growth Performance,Feed Utilization and Metabolism of Litopenaeus vannamei

为探究包膜蛋氨酸对凡纳滨对虾(Litopenaeus vannamei)幼虾生长性能、饲料利用和代谢的影响,在蛋氨酸含量占干物质0.54%的基础饲料(G1)中添加包膜蛋氨酸,配制5组等氮等能的饲料,饲料中蛋氨酸含量分别为干物质的0.54%(G1)、0.72%(G2)、0.93%(G3)、1.07%(G4)和1.33%(G5)。选取初始体质量为(0.75±0.01)g的凡纳滨对虾,在室内养殖系统中进行为期42 d的养殖实验,实验结束后分析包膜蛋氨酸对对虾生长性能、饲料利用、消化酶活力及抗氧化力的影响。研究显示,G3组对虾的末均质量和增重率显著高于G1和G5组(P<0.05),且G3组的特定生长率显著高于G1组(P<0.05)。G3组的粗脂肪含量显著高于G1和G5组(P<0.05)。G3组的饲料系数显著低于G1组(P<0.05),G3组的蛋白质效率和脂肪沉积率显著高于G1和G5组(P<0.05),G3、G4和G5组的饲料蛋白质和干物质表观消化率显著高于G1和G2组(P<0.05)。G3组的胰蛋白酶活性显著高于G5组(P<0.05),G3组的脂肪酶活性显著高于G1和G5组(P<0.05)。此外,适宜的包膜蛋氨酸添加显著提高了凡纳滨对虾的肝胰脏和血淋巴的抗氧化能力。研究结果表明,在本研究的条件下,以特定生长率为指标,通过二次曲线回归拟合分析显示,凡纳滨对虾对包膜蛋氨酸的最适需求量为饲料干物质的0.96%(占饲料粗蛋白的2.23%)。

In order to investigate the effects of coated methionine on the growth performance,feed utilization and metabolism of juvenile Litopenaeus vannamei,5 isonitrogenous and isoenergetic diets were formulated by adding coated methionine into the basal diet(G1)with methionine content of 0.54%dry matter.Methionine content was 0.54%(G1),0.72%(G2),0.93%(G3),1.07%(G4)and 1.33%(G5)of dry matter,respectively.Juvenile L.vannamei with an initial body weight of(0.75±0.01)g were selected and cultured in an indoor culture system for 42 days.After the feeding trial,the growth performance,feed utilization,activities of digestive enzymes and antioxidant capacity were determined.The results showed that the final average weight and weight gain rate of juvenile shrimp in G3 group were significantly higher than those in G1 and G5 groups(P<0.05).The specific growth rate in G3 group was significantly higher than that in G1 group(P<0.05).The crude fat content in G3 group was significantly higher than that in G1 and G5 groups(P<0.05).In addition,the feed conversion ratio in G3 group was significantly lower than that in G1 group(P<0.05).The protein efficiency and fat deposition rate in G3 group were significantly higher than those in G1 and G5 groups(P<0.05),and the protein deposition rate in G2,G3 and G4 groups was significantly higher than that in G1 and G5 groups(P<0.05).The apparent digestibility of protein and dry matter in G3,G4 and G5 groups was significantly higher than that in G1 and G2 groups(P<0.05).The trypsin activity in G3 group was significantly higher than that in G5 group(P<0.05),and lipase activity in G3 group was significantly higher than that in G1 and G5 groups(P<0.05).In addition,the appropriate supplemental level of coated methionine significantly increased the hepatopancreas and hemolymph antioxidant capacity.The results showed that the methionine requirement of juvenile L.vannamei was 0.96%of dietary dry matter(dietary methionine content accounted for 2.23%of dietary crude protein).