Comparative analysis of the fatty acid profiles and milk fat globule membrane proteome in human and small ruminant colostrum and mature milk using data-independent acquisition for targeted infant nutrition improvement

Small ruminant milk may offer a viable alternative to cow milk, whereas human milk, the gold standard for infant nutrition, exhibits dynamic composition. This study analyzed the milk fat globules (MFG) particle size, fatty acid (FA) composition, and milk fat globule membrane (MFGM) proteome in human, goat, and sheep colostrum and mature milk. The smallest and largest average MFG particle sizes were identified in goat colostrum and sheep mature milk, respectively. Unsaturated FA were most prevalent in human colostrum (HC; 70.04%), whereas small ruminant milks were characterized by a higher proportion of saturated FA (57.07%-77.77%). The differential expression of FA is speculated to be associated with the variation in FA metabolic proteins on MFGM. A total of 1,658 MFGM proteins were identified. Compared with small ruminant milks, glycolysis-related proteins, such as phosphoglycerate mutase and pyruvate kinase, and antigen-presenting proteins, such as toll-like receptors and HLA molecules, were most abundant in HC, with higher levels of antioxidant-related proteins observed in human mature milk (HM). By emphasizing the differences in MFG between HC, HM, and small ruminant milk from the perspectives of particle size, FA, and proteomics, this study provides data supporting the personalized improvement of infant formula.