Fatty acid profiles in Chinese Maiwa yak milk across the lactation cycle

Abstract

An experiment was conducted to determine fatty acid (FA) profiles in Chinese Maiwa yak milk across the lactation cycle. Sixty-one healthy, similar weight, 4-7 years old, 3-6 parity Maiwa yaks with unrelated background were selected randomly from Hongyuan County, Sichuan province, in southwest of China (with the altitude over 3500 m). The yaks graze on natural pasture all year around without irrigation, fertilizer, or other changes to the pasture. The samples for each animal were collected separately at 1, 2, 3, 4, 5, 6, 7, 15, 30, 60, 120 and 180 days postpartum for fatty acid composition analysis. The most abundant FA species in yak milk were C16:0, C18:1c9, C18:0 and C14:0, all of which varied significantly with the lactation periods. C10:0, C12:0, C14:0 and C16:0 was positively correlated with each other, and negatively correlated with C18:0. C18:2t9c11 was negatively correlated with saturated FA (SFA). C18:1t11, iso-C15:0, C22:0 and C16:1c7 were located in the central positions of the correlation network. C18:1t11 showed close correlation with C18 unsaturated fatty acid (UFA) (C18:1t13 and C18:3n3), C16:0, C19:0, and anteiso-C17:0. Besides with each other, iso-C15:0 and C22:0 were associated with C15:0, anteiso-C15:0, C19:0, C20:0, and C20:0, anteiso-C15:0, iso-C14:0, 9,10-hexyl-C17:0, respectively. C16:1c7 was closely associated with C13:0, C17 FA (C17:0 and 9, 10-hexyl-C17:0), C16:1c9, C20:5n3 and C20:4n6. In conclusion, these data will be informative for the study on the regulatory mechanism of milk FA formation in yaks.