Authors : Xian Guo, Min Chu, Jie Pei, Xuezhi Ding, Pengjia Bao, Chunnian Liang and Ping Yan
Abstract: Yak in the Qinghai-Tibetan Plateau depends mainly on grazing and milk is one of its main products. In this study, the compositions of yak milk such as nutrient ingredients, amino acids and fatty acids were measured. The results showed that ingredients of yak milk, rate of colostrum milk protein and rate of milk fat were significantly higher (5.43 and 5.70 vs 4.84 and 4.57%, respectively) than that in the normal milk. Sixteen types of amino acids were detected in the yak milk with relatively higher content of glutamic acid, isoleucine, tyrosine and arginine and relatively lower content of lysine, glycine, methionine and phenylalanine. Total amino acid content (5.485%) in the yak colostrum was significantly higher than that in the normal milk (3.065%). Twenty-eight types of fatty acids, 19 types of saturated fatty acids and 9 types of unsaturated fatty were detected in the yak colostrum and mature milks. Myristic acid, 15-methyl palmitic acid, cis-octadecanoic acid, nonadecanoic acid, oleic acid and cis-11-oleic acid were the main fatty acids in the colostrum; While oleic acid, 15-methyl palmitic acid, stearic acid, 15-methyl hexadecanoic acid, nonadecanoic acid, heneicosanoic acid and behenic acid were the main fatty acids in the mature milk. Contents of oleic acid and stearic acid were significantly higher in the mature milk than in the colostrum. Results of this study could not only provide the basic data and reference material for understanding the nutritional value of yak milk but also help to promote the development and utilization of yak milk.
Xian Guo, Min Chu, Jie Pei, Xuezhi Ding, Pengjia Bao, Chunnian Liang and Ping Yan, 2015. Chemical Compositions and Nutrients Profiling of Yak Milk in Chinese Qinghai-Tibetan Plateau. Journal of Animal and Veterinary Advances, 14: 315-319.