Lipids in bovine milk have several biological activities, with implications for human health and the physical functionality of foods. However, alterations in the lipid profile of bovine milk during lactation are not well-studied. This study aimed to identify differences in lipids between bovine colostrum and mature milk, using a lipidomics approach. Using an advanced mass spectrometry-based quantitative lipidomics approach, 335 lipids assigned to 13 subclasses were characterized in bovine colostrum (BC) and mature milk (BM). In total, 63 significantly differential lipids (SDLs) were identified. Among the 63 SDLs, the levels of 21 lipids were significantly lower in BM than in BC, including 5 glycerophosphatidylethanolamines (PEs), 1 glycerophosphatidylglycerol (PG), and 15 triacylglycerols (TGs). The levels of the remaining 42 lipids increased in BM, including 1 cardiolipin (CL), 9 diacylglycerols (DGs), 9 dihexosylceramides (Hex2Cers), 3 hexosylceramides (HexCers), 3 glycerophosphatidic acids (PAs), 2 glycerophosphatidylcholines (PCs), 12 PEs, and 3 TGs. Furthermore, the correlations and related metabolic pathways of these 63 SDLs were analyzed to explore the mechanisms that alter bovine milk lipids during lactation. The seven most relevant pathways identified herein, ranked in accordance with their degree of influence on lactation, were glycerophospholipid metabolism, sphingolipid metabolism, glycerolipid metabolism, glycosylphosphatidylinositol-anchor biosynthesis, linoleic acid metabolism, alpha-linolenic acid metabolism, and arachidonic acid metabolism. Our results provide essential insights into mechanisms underlying alterations in bovine milk lipids during different lactation periods, along with practical information of specific nutrition and quality assessments for the dairy industry.

牛乳中的脂质具有多种生物活性，对人体健康和食品的物理功能具有影响。然而，尚未充分研究泌乳期间牛乳脂质分布的变化。这项研究旨在通过脂质组学方法确定牛初乳和成熟牛奶之间的脂质差异。使用基于质谱的先进定量脂质组学方法，在牛初乳（BC）和成熟牛奶（BM）中表征了分配给13个亚类的335种脂质。总共鉴定出63种差异显着的脂质（SDL）。在这63个SDL中，BM中21种脂质的水平显着低于BC，包括5种甘油磷脂酰乙醇胺（PEs），1种甘油磷脂酰甘油（PG）和15种三酰甘油（TGs）。BM中剩余的42种脂质的水平增加，包括1种心磷脂（CL），9种二酰基甘油（DGs），9种二己糖基神经酰胺（Hex2Cers），3种己糖基神经酰胺（HexCers），3种甘油磷脂酸（PAs），2种甘油磷脂酰胆碱（PCs）， PE和3个TG。此外，分析了这63个SDL的相关性和相关的代谢途径，以探索在泌乳过程中改变牛乳脂质的机制。根据它们对泌乳的影响程度，本文确定的七个最相关的途径是甘油磷脂代谢，鞘脂代谢，甘油脂代谢，糖基磷脂酰肌醇固定生物合成，亚油酸代谢，α-亚麻酸代谢和花生四烯酸代谢。