中文摘要：

本试验旨在研究断奶时间及日龄变化对湖羊羔羊肌肉中脂肪酸组成的影响。试验选取体重[（3.51±0.57）kg]接近、健康状况良好的54只初生湖羊公羔,饲养至28日龄后屠宰6只。将剩余的48只按照同质性原则分为28日龄断奶组[（8.21±0.97）kg]和56日龄断奶组[（8.06±0.53）kg],每组24只。2组在42、56、70、84日龄分别屠宰6只,屠宰后测定羔羊背最长肌脂肪酸组成和瘤胃中氢化菌含量。结果表明：1）56日龄断奶组肌肉中大部分脂肪酸的含量高于28日龄断奶组;随着日龄的增长,羔羊肌肉中脂肪酸的含量逐渐升高,种类变得越来越多。2）70日龄时,28日龄断奶组的瘤胃中溶纤维丁酸弧菌含量显著高于56日龄断奶组（P〈0.05）;56日龄断奶组瘤胃中溶纤维丁酸弧菌的含量在42日龄时显著高于70和84日龄（P〈0.05）。由此可见,与28日龄断奶相比,羔羊在56日龄断奶更利于肌肉中脂肪酸的沉积。

英文摘要：

This experiment was conducted to study the effects of weaner time and days of age on muscle fatty acid composition of Hu lambs. Fifty four healthy new born male Hu lambs with similar body weight [（ 3. 51 ±0.57） kg] were selected and reared to 28 days of age,six of them were slaughtered,and the rest 48 lambs were randomly divided into 28 and 56 days of age weaner groups with 24 lambs per group. Six lambs from each group were slaughtered at 42,56,70,84 and 56 day of age,respectively. The fatty acid composition of longissimus and hydrogenated bacteria content in rumen were determined. The results show ed as follow s： 1）most muscle fatty acid contents in 56 days of age weaner group were higher than those in 28 days of age weaner group; with the increase of days of age,muscle fatty acid contents gradually increased and the species become more and more abundant. 2） At 70 days of age,Butyrivibrio fibrisolvens content in rumen in 28 days of age weaner group was significantly higher than that in 56 days of age weaner group（ P〈0.05）; in 56 days of age weaner group,the content at 42 days of age was significantly higher than that at 70 and 84 days of age（ P0.05）. Thus,compared with weaning at 28 days of age,weaning at 56 days of age is more helpful for fatty acid deposition in muscle of lambs.