中文摘要：

选取了初生、1～6月龄湖羊公羔和12月龄的周岁公羊各5只,采用real-time PCR检测湖羊不同部位肌肉黑素皮质激素受体4基因（MC4R）mRNA表达水平,分析MC4R mRNA表达的发育性变化及其与肌肉肌内脂肪含量的关系。结果发现：湖羊不同肌肉部位MC4R基因表达的发育性变化模式均为先上升后下降。其中3月龄背最长肌、后腿股二头肌和前腿肱二头肌的MC4R mRNA表达水平达到最大,与其余各月龄相比差异显著,而2月龄腰大肌的MC4R mRNA表达水平达到最大,5月龄MC4R mRNA表达水平在湖羊不同部位肌肉间表现有明显差异,但无明显规律,其后各月龄间均无显著差异。结论：湖羊背最长肌、腰大肌和后腿股二头肌MC4R mRNA表达水平与肌内脂肪（IMF）含量呈负相关关系。

英文摘要：

In the study,five male Hu sheep of newborn,1-6 month age and 12 month age were selected,and detected were the melanocortin 4 receptor gene（MC4R）mRNA expression by real-time PCR in longissimus dorsi muscle,psoas major muscle,biceps femoris muscle and biceps brachii muscle,and analyzed was the relationship between the developmental changes of the MC4R mRNA expression and intramuscular fat（IMF）content in muscles.The results showed that the MC4R gene expression patterns of Hu Sheep different muscle parts increased and then decreased.Among them,MC4R gene of longissimus dorsi muscle,biceps femoris muscle and biceps brachii muscle had the highest level at the 3rd month,with a significant difference compared with other months,while psoas major muscle MC4R gene expression had the highest level at the second month.There were significant differences of MC4R mRNA expression level of 5-month-old among different muscle but no significant laws.MC4R mRNA expression levels in longissimus dorsi muscle,psoas major muscle and biceps femoris muscle of Hu sheep was negatively correlated to intramuscular fat content.