Variations in fatty acid composition of Laoshan goat milk from partum to 135 days postpartum

The objective of this study was to characterize the variations in fatty acid (FA) profile during 7 days of colostrum production and 5 months of mature milk production in Laoshan goats. The individual FA profiles of each sample were investigated by gas chromatography-mass spectrometry. Significant differences in FAs were found between colostrum and mature milk. The contents of saturated fatty acids (SFA), unsaturated fatty acids (UFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA), and sum of C6, C8, and C10 (S_C6+C8+C10 ) were all significantly affected by lactation period. Furthermore, there was no significant difference in the ratio of UFA/SFA or C18:2 (cis9, cis12-octadecadienoic acid)/C18:3 (all cis-9,12,15-octadecatrienoic acid) during the lactation period. The highest concentrations of S_C6+C8+C10 , UFA, MUFA, and PUFA appeared in colostrum, but the highest SFA content was in mature milk. The highest proportions of S_C6+C8+C10 and SFA were 11.32% and 79.55% on 5th day and 135th day respectively. By contrast, the lowest proportion of UFA was 20.45% on the 135th day. C14:0 (10.93%-12.87%), C16:0 (27.54%-36.65%), C18:0 (10.47%-14.59%), and C18:1 (18.80%-30.61%) were the most predominant FAs in goat milk with significant differences during the 135 days lactation period except C18:0. In conclusion, the results of this study suggest that the lactation time has a pronounced effect on the FA compositions of goat milk.