夏季高原牧草脂肪酸与牦牛乳脂脂肪酸特征及相关性研究

Summer Forage Grass Fatty Acids and Yak Milk Fatty Acids and Its Correlation in Qinghai-Tibet Plateau

通过测定青海省海北藏族自治州和甘肃省甘南藏族自治州的新鲜牦牛乳脂脂肪酸与当地牧草脂肪酸情况,探索和揭示牧草和牦牛乳脂脂肪酸组成特征及其相关性。采取两地区夏季牧场新鲜牧草和牦牛乳酥油,利用GC-MS进行脂肪酸分析。结果表明:海北牧草中共检测出28种脂肪酸,甘南牧草中检出33种脂肪酸,两地区牧草中PUFA含量差异大(72.12%±0.95%和8.39%±0.04%);海北酥油中共检测出脂肪酸37种,甘南酥油中共检测出脂肪酸34种;两地区酥油种类呈现相似种类模式;海北地区牧草中LCFA与酥油中LCFA的含量呈现正的强相关(R=0.86),牧草和酥油中的OCFA呈现负的强相关(R=-0.97);SBCFA也呈现强的负相关(R=-0.99);甘南地区牧草中的UFA和酥油中的UFA呈现极强的负相关性(R=-0.96),而与SFA呈现极强的正相关性(R=0.97)。说明,两地区牧草脂肪酸种类及含量差异显著,两地区酥油表现出类似的种类模式,乳脂肪酸的种类和含量与牦牛食草的情况,以及反刍动物瘤胃的代谢机制有关。牧草脂肪酸与乳脂肪酸之间的相关性揭示高原牧草对牦牛乳脂肪酸高品质的优越贡献。

The fatty acids in fresh yak milk fat and local pasture in Haibei Tibetan Autonomous Prefecture of Qinghai province and Gannan Tibetan Autonomous Prefecture of Gansu province were determined to explore and reveal the composition characteristics and correlation of the fatty acids in pasture and yak milk.Fresh herbage and yak butter were used to analyze fatty acids by gas chromatography.The results showed that:(1)a total of 28 fatty acids in the herbage of Haibei and Gannan were detected.PUFA content in the herbage of Haibei and Gannan was significantly different(72.12%±0.95%vs 8.39%±0.04%).(2)37 kinds of fatty acids were detected in Haibei ghee,34 kinds of fatty acids were detected in Gannan ghee.The types of shorgening in the two regions presented similar patterns.(3)LCFA in herbage in Haibei region had strong correlation with LCFA content in shortening(R=0.86),while OCFA in herbage and shortening had strongly negative correlation(R=-0.97).SBCFA also presented a strong negative correlation(R=-0.99).UFA in herbage in Gannan had strongly negative correlation with UFA in shortening(R=-0.96),and strongly positive correlation with SFA(R=0.97).In conclusion,there are significant differences in the types and contents of fatty acids in herbage between the two regions.The types and contents of fatty acids in milk are related to yak grazing and ruminant metabolism.The correlation between forage fatty acids and milk fatty acids reveal the superior contribution of plateau forage to the high quality of yak milk fatty acids.