中文摘要：

摘要：以初始体质量为（5．49±0．01）g的大菱鲆幼鱼为实验对象，探讨饲料中过量添加晶体蛋氨酸或蛋氨酸羟基类似物对大菱鲆生长、饲料利用和抗氧化反应的影响。以白鱼粉和豆粕为主要蛋白源，饲料中同时添加0．25％DL-蛋氨酸和0．3％蛋氨酸羟基类似物钙盐（MHA）作为对照，在此基础上分别添加0．5％DL-蛋氨酸、1．25％DL-蛋氨酸、0．59％MHA、1．49％MHA、1。25％DL-蛋氨酸＋0．85％柠檬酸钙，配制出6种实验饲料，使饲料中蛋氨酸和蛋氨酸羟基类似物（HMTBA）含量分别是1．35％、1．83％、2．50%、1．45％、1．37％、2．51％和0．22％、0．22％、0．22％、0．63％、1．38％、0．29％。养殖试验在室内流水系统中进行，持续10周，每个处理设5个重复，每个重复放养大菱鲆幼鱼30尾。结果显示，过量添加DL-蛋氨酸和HMTBA对大菱鲆幼鱼生长无显著影响（P〉0．05）。过量添加DL-蛋氨酸和HMTBA对大菱鲆体组分、肥满度（CF）、脏体比（VSI）和肝体比（HSI）均无显著影响（P〉0．05），但柠檬酸钙添加组（处理6）体蛋白含量与基础饲料组相比显著降低（P〈0．05）。对大菱鲆肝脏过氧化氢酶（CAT）、超氧化物歧化酶（SOD）和肝脏硫代巴比妥酸反应产物量（TBARS）进行测定，各处理组间均无显著性差异（P〉0．05）。结果显示，在该实验条件下，过量添加晶体蛋氨酸（1．31-1．73倍）和HMTBA（1．32-1．75倍）对大菱鲆幼鱼的生长、饲料利用和抗氧化反应没有显著影响。

英文摘要：

A growth experiment was conducted to evaluate the influence of overdose dietary DL-methio- nine （Met） or 2-Hydroxy-4- （Methylthio）： butanoic acid （HMTBA） on turbot （iniqal body weight. （5.49 ±0. 01） g）. The control contained 1. 35% Met and 0. 22% HMTBA. Five different doses of Met or HMTBA were added to the basal diet, respectively. Finally, 6 experimental diets were formulated, and the analyzed levels of Met or HMTBA in diets are as follows. Met： 1.35%, 1.83%, 2. 50%, 1.45%, 1.37%, 2. 51%; HMTBA. 0. 22%, 0. 22%, 0. 22%, 0. 63%, 1.38% and 0. 29%. Each diet was fed to five replicate groups of turbot for 10 weeks. Results showed that no significant differences in growth re- sponses were found among dietary treatments （P〉0. 05）. No significant difference was observed in body composition, condition factor （CF）, visceral indexes （VSI）, and hepatosomatic indexes （HSI） （P〉0.05）, but the content of body protein of fish in treatment of diet 6 was significantly lower than those in the control and diet 2 （P〈0. 05）. No significant differences in hepatic catalase activity, supemxide dis- mutase activity, thiobar-bituric acid reactive substances value were found iri liver （P〉0.05）. In conclu- sion, overdose dietary DL-Met （1.31-1.73 times） or HMTBA （1.32-1.75 times） had no significant effects on growth, feed utilization and anti-oxidant responses in turbot under the current experimental conditions.