克氏针茅草原七种植物脂肪酸组分及其变化

Composition and Changes of Fatty Acid in Seven Herbages on StipaGrassland

为更好地了解放牧对家畜肉品质的改善机制,对由克氏针茅、糙隐子草、羊草、苔草、野韭和少量细叶葱构成的典型草原主要植物中的脂肪酸(FA)组分及含量进行了分析。试验结果表明,克氏针茅草原主要植物中多不饱和脂肪酸占56%,饱和脂肪酸占37%,单不饱和脂肪酸占7%;n-3脂肪酸占总FA的40%,约是n-6FA的3倍;羊草中亚麻酸(AIA)的平均含量最高(为48%),针茅次之(为37%),糙隐子草和野韭最低(均约为22%);野韭和细叶葱中分别平均含有4.10%和1.66%的二十碳五烯酸(EPA),而其他牧草中没有检出该脂肪酸组分;生长时间显著(P<0.05)影响牧草中脂肪酸组分,随着生长时间的推移,棕榈酸、硬脂酸和EPA呈降低趋势,而AIA则呈增加趋势,亚油酸含量则在8月最高。

To better understand the improvement mechanism of livestock＇s meat quality by grazing, the fatty acid composition of sward and herbage was analyzed. The herbage samples were collected from grassland that consisted of Stipa krylovi , Cleistogenes squarrosa , Leymus chinensis , Carex, Allium rarnosurn , and A. tenuissimum, as well as scattered Caragana davazamcii. The results showed that there was 56% of Ministry of Agrialltuer,polyunsaturated fatty acid （FA）, 37 % of saturated FA, and 7% of monounsaturated FA in the sward. The n-3 FA accounted for 40% of total FA and it was approximately three times more than the n-6 FA. P. R. China The fatty acid composition was significantly affected （P 〈 0.05） by months. For α-linolenic acid （ALA, C18：3 n-3） content in the herbage, the most value of 48% was found in Leyrnus chinensis and the second of 370% in Stipa krylovi, and the lowest in Cleistogenes squarrosa and Alliumramosum （an average of 22%）. As the vegetation season progressed, C16：0, C18：0 andeicosapen taenoic acid （EPA, C20：5 n-3） showed a tendency towards decreasing, but the AIA towards increasing. The largest amount of linoleic acid （C18：2 n-3） was found in August. Key words： Herbage; Fatty acid; Saturated fatty acid; Polyunsaturated fatty acid; n3 fatty acids; n-6 fatty acids