Abstract:

In order to study the contents and composition of fatty acids in meat of Tibetan sheep at different altitudes under natural grazing conditions， 6 ewes （3 years old） of Tibetan sheep at different elevations were selected， including high （4 500 m）， middle （3 500 m） and low （2 500 m） altitudes. The composition and contents of fatty acids in longissimus dorsi， foreleg muscle and hindleg muscle were determined. The results showed that there were significant differences in fatty acid composition and content among Tibetan sheeps at different altitudes. Among them， the content of myristic acid （C14∶0） was the lowest in 3 muscle tissues of Tibetan sheeps at low altitude. And the content of oleic acid （C18∶1n9c） was the highest in 3 muscle tissues of Tibetan sheep at low altitude， which was significantly higher than that at middle and high altitudes. The ratios of polyunsaturated fatty acids （PUFA） to saturated fatty acids （SFA） （P/S） in different muscle tissues were from 0.168 to 0.504， and the P/S value of the longissimus dorsi muscle of Tibetan sheep at high altitude was significantly higher than that of middle and low altitudes. To sum up， except the longissimus dorsi of Tibetan sheep at high altitude area， the composition of fatty acids in different muscle tissues of Tibetan sheep at low altitude area had more advantages， which had good edible value and potential to produce high-grade mutton.

Key words: altitude, Tibetan sheep, meat quality, fatty acids

摘要：

为明确自然放牧条件下不同海拔藏绵羊肉质脂肪酸含量及组成特征，选择高（4 500 m）、中（3 500 m）、低（2 500 m）海拔藏绵羊各6只（3岁母羊），测定其背最长肌、前腿肌和后腿肌中的脂肪酸组成及含量。结果表明，不同海拔藏绵羊脂肪酸组成及含量存在显著差异，其中，肉豆蔻酸（C14∶0）在低海拔藏绵羊不同肌肉组织中含量最低；油酸（C18∶1n9c）在低海拔藏绵羊不同肌肉组织中含量最高，并显著高于中、高海拔。不同肌肉组织中的多不饱和脂肪酸（polyunsaturated fatty acid， PUFA）与饱和脂肪酸（saturated fatty acid， SFA）的比值（P/S）在 0.168~0.504之间，其中高海拔藏绵羊背最长肌的P/S值显著高于中、低海拔。由此表明，藏绵羊不同肌肉组织中脂肪酸的组成除高海拔区背最长肌外，低海拔更具优势，即生长在低海拔的藏绵羊具有更好的食用价值及生产高档羊肉的潜力。

关键词: 海拔, 藏绵羊, 肉品质, 脂肪酸