Abstract: To investigate the differences in amino acid and fatty acid composition of lamb meat under different grazing intensity and supplementary feeding level,seventy-two 3-month-old male Hulunbuir lambs were selected from the Inner Mongolia,and a two-factor (grazing intensity and supplementary feeding level) randomized block design was used. The grazing intensity included moderate grazing (MG) and heavy grazing (HG);supplementary feeding level included no supplementation (NS),1% body weight supplementation (S1) and 2% body weight supplementation (S2),a total of 6 treatments. The results showed that the intramuscular fat (IMF) content of MG lambs was significantly higher than HG;the IMF and protein contents of S2 lambs were significantly higher than NS. The total amino acid contents of HG and S2 lambs were significantly higher than those of MG and NS. Compared to NS,S2 lamb decreased by 17.14% and 20.59% in docosanoic acid and tricosanoic acid contents,respectively,and increased by 30.91% and 21.97% in t10,c12-conjugated linoleic acid and total unsaturated fatty acid contents,respectively,with an n6/n3 ratio of less than five. In summary,the feeding regimes of moderate grazing combined with supplementary feeding is conducive to the production of lamb meat with high-quality protein and fatty acid composition,as well as to the sustainable development of grassland.

Key words: Grazing intensity, Supplementary level, Lamb meat, Amino acid, Fatty acid

摘要： 试验旨在研究不同放牧强度和补饲水平下羊肉氨基酸和脂肪酸组成的差异。在内蒙古呼伦贝尔草原选取3月龄呼伦贝尔羊72只，采用双因素(放牧强度和补饲水平)随机区组试验设计，放牧强度包括适度放牧(MG)和重度放牧(HG)；补饲水平包括不补饲(NS)、1%体重补饲量(S1)和2%体重补饲量(S2)，共6个处理。结果表明：MG羔羊肌内脂肪(IMF)含量显著高于HG；S2羔羊IMF，蛋白质含量显著高于NS。HG和S2羊肉总氨基酸含量显著高于MG和NS；相较于NS，S2羊肉中山萮酸和二十三碳酸含量分别降低了17.14%和20.59%，t10,c12共轭亚油酸和总不饱和脂肪酸含量分别增加了30.91%和21.97%，n6/n3比值小于5。综上，适度放牧结合补饲的饲养策略，有利于生产具有优质蛋白质和脂肪酸组成的羊肉，并有利于草原的可持续发展。

关键词: 放牧强度, 补饲水平, 羊肉, 氨基酸, 脂肪酸