不同泌乳期牦牛乳中奇数与支链脂肪酸的分布

采集全乳期（6、7、8月）和半乳期（3月）的牦牛乳，牧场海拔范围为2 835～3 719 m。采用气相色谱-质谱分析方法，对不同泌乳期牦牛乳中奇数与支链脂肪酸的分布进行分析。结果显示，海拔高度2 835～3 719 m的不同地区（果洛州、海南州、海西州乌兰县、海北州祁连县）牦牛乳中奇数与支链脂肪酸没有显著差异，在半乳期时，牦牛乳中的奇数脂肪酸含量差异显著（P＜0.05），支链脂肪酸含量差异极显著（P＜0.001）。研究表明，半乳期时（3月）牦牛乳中的奇数与支链脂肪酸含量最高，在全乳期和半乳期，牦牛乳中奇数与支链脂肪酸的含量明显高于普通牛乳。

Distribution of Odd and Branched Chain Fatty Acids (OBCFA) of Yak Milk from Different Lactations

Yak milk samples from the full lactation (June, July, and August) and half lactation periods (March) at altitudes
ranging from 2 835 to 3 719 meters were collected and analyzed by gas chromatography-mass spectrometry (GC-MS) for
the distribution of odd and branched fatty acids (OBCFAs) at different lactations. The results showed that no significant
differences in OBCFAs of yak milk samples were found between different regions (Guoluo, Hainan, Wunan, and Qilian).
For the half lactation period, significant difference in odd chain fatty acids (OCFAs) (P < 0.05) and extremely significant
differences in branched chain fatty acids (BCFAs) (P < 0.001) were found among different regions. The concentrations of
both OCFAs and OBCFAs were the highest in the half lactation period (March) of yak milk, and significantly higher than
those of cow milk at both lactations.