中文摘要：

本研究旨在研究蛋氨酸（MET）和蛋氨酸羟基类似物（HMTBA）对饲喂高脂饲粮小鼠自由基水平、料重比、营养物质消化率和肌肉生长的影响。选用60只昆明种雄性小鼠分成4组,分别是正常＋0.2%MET组、正常＋0.1%MET＋0.1%HMTBA组、高脂＋0.2%MET组、高脂＋0.2%HMTBA组。饲喂4周,测定自由基、腿肌率、基因相对表达量等指标。结果显示：与正常＋0.2%MET组相比,高脂＋0.2%MET组血液和组织的自由基水平显著提高（P〈0.05）,导致小鼠氧化应激,而高脂＋0.2%HMTBA组自由基水平下降,与正常＋0.2%MET组接近;高脂组中HMTBA的添加,显著提高了小鼠的粗蛋白质、粗脂肪消化率,降低了料重比（P〈0.05）;同时提高了肝脏、空肠组织胰岛素样生长因子-Ⅰ（IGFⅠ-）基因的相对表达量,显著提高了小鼠的腿肌率和肌肉组织Myogegin基因的相对表达量,降低了Myostatin基因的相对表达量（P〈0.05）。结果表明：适量的HMTBA能够有效清除体内的自由基,降低料重比,提高营养物质消化率,促进动物肌肉生长,提高与肌肉生长正相关基因的表达量。

英文摘要：

The aim of this research is to observe the effects of methionine（MET） and its hydroxy analogue 2-hydroxy-4-（methythio） butanoic acid（HMTBA） on the levels of free radicals,the ratio of feed to gain,nutrient digestibility,and muscle growth of mice fed high-fat diet.Sixty KM male mice were randomly divided into 4 dietary groups： control-fat diet with 0.2% MET,control-fat diet with 0.1% HMTBA and 0.1% MET,high-fat diet with 0.2% MET,and high-fat diet with 0.2% HMTBA,respectively.The free radicals,leg muscle proportion and relative expression of related genes were determined after 4 weeks.The results showed that compared with the control-fat diet with 0.2% MET group,high-fat diet with 0.2% MET increased the level of free radicals in whole blood and tissues significantly（P0.05） and resulted in oxidative stress,but the levels of free radicals of the mice fed high-fat diet with 0.2% HMTBA were decreased to the levels close to the control group.Because of the addition of HMTBA,the digestibility of protein and fat of the mice fed high-fat diet were increased significantly（P0.05）,and the ratio of feed to gain were decreased significantly（P0.05）;the relative expression yield of the gene of IGF-Ⅰ in liver and jejunum was increased;the leg muscle proportion of the mice and the relative expression yield of gene Myogegin in the muscle were increased,while the relative expression yield of gene Myostatin was decreased significantly（P0.05）.In conclusion,appropriate levels of dietary HMTBA can effectively eliminate free radicals in mice fed high-fat diet,reduce the ratio of feed to gain,improve nutrient digestibility,and promote muscle growth and expression yield of positively related genes.