饲料中添加赖氨酸及蛋氨酸对罗非鱼生长的影响

Effect of Lysine/Methionine on Tilapia(Oreochromis niloticus) Growth

以平均初始体质量5g的罗非鱼为试验对象，在赖氨酸（Lys）及蛋氨酸（Met）均呈缺乏状态的基础饲料中，分别补充结合态Lys（PBL），晶体Lys（UCL）和包膜Lys（CL）等3种形式的Lys，晶体Met（UCM）、包膜Met（CM）和羟基蛋氨酸钙（MHA—Ca）等3种形式的Met，共配制8组等氮等能饲料，每个组设3个重复，每个重复30尾，实验水温24～30℃，持续56d。结果表明，对照组增质量率317．99％，单独补充质量分数0．15％PBL、0．15％UCL、0．15％CL3种形式外源Lys的增质量率分别是326．93％，337．02％、329．42％，对罗非鱼的生长无显著影响，但同时补充质量分数0．15％CL及0．1％CM，罗非鱼增质量率为353．22％，显著提高了罗非鱼的生长水平；而同时补充质量分数0．15％UCL及0．1％UCM、0．15％PBL及0．1％UCM、0．15％PBL及0．1％MHA—Ca的增质量率分别为304．159／5、308．78％、337．19％，对罗非鱼的生长无显著影响。补充外源氨基酸对罗非鱼肝脏水分有降低趋势，对其它常规组成及肌肉氨基酸组成无明显影响。结果提示，包膜赖氨酸及包膜蛋氨酸在适宜的补充方式下，对罗非鱼的促生长效果要优于其它形式的赖氨酸及蛋氨酸，可有效平衡罗非鱼饲料配方的赖氨酸及蛋氨酸水平的不足。

An 8-week experiment was conducted to investigate the effects of lysine and methionine in different forms and comb lysine PBL, coated methioni MHA-Ca） on the growth, niloticus . with eight isonitro ination （coated lysine CL, uncoated lysine UCL, protein--bound ne CM, uncoated methionine UCM, methionine hydroxy analog-Ca body composition, and muscle amino acid content of Oreochromis genous and isoenergetic （30% crude protein, 16kJ/g gross energy） diet . At the end of the growth trial, the fish fed the PBL diet, UCL diet, CL diet and PBL/ MHA-ea diet intended to higher weight gain compared with that of the control （P〉0.05）, while the fish fed the CL/CM diet showed significantly higher growth rate than those fed the other diets （P〈0.05） except PBL/MHA diet, the weight gain was similar between the fish fed the UCL/UCM diet and PBL/UM diet, and it was lower compared to the other groups. The composition of whole body and muscle （dry matter, protein, lipid, ash） and protein content of liver do not affected by the dietary treatment （P〉0.05）, while water content of the liver was significantly lower in fish fed the test diets than the control diet （P〈0.05）. the overall AA pattern of the muscle protein was not significantly affected by the dietary treatment （P〉0.05）. Results of this study indicate that the combination of coated methionine and lysine was an effective form in balancing amino acid pattern of diet which is deficient in methionine and lysine for Oreochromis.niloticus.