Effect of Nutritional Intervention on the Milk Fat Globule Membrane Proteome of Colostrum From Lactating Yaks

PURPOSE: This study aimed to investigate the effects of nutritional intervention on the milk fat globule membrane (MFGM) proteome of colostrum from lactating yaks to provide a theoretical basis for understanding potential links to yak colostrum quality and calf health. MATERIALS: Twenty healthy pregnant yaks were randomly assigned to a control group (grazing) and a nutritional intervention group (grazing + supplemental feeding with 1.0 kg concentrate and 3.0 kg oat hay). The trial lasted for 21 days prepartum and 7 days postpartum. Colostrum samples collected from days 1-7 postpartum were analyzed. Data-independent acquisition (DIA) proteomics technology was used to analyze differences in MFGM protein expression, and bioinformatics analysis (GO, KEGG) was also performed to interpret the functions of differentially expressed proteins (DEPs). RESULTS: A total of 1972 MFGM proteins were identified, and 661 DEPs were screened. Among them, 85 DEPs were significantly upregulated in the TR group (α-S1-casein, α-S2-casein, κ-casein, and glutathione peroxidase (GPX3)), and 576 were downregulated (xanthine oxidase (XDH) and perilipin (PLIN2)) GO enrichment analysis revealed that DEPs were associated with immune effector processes, complement activation, and antioxidant responses. KEGG pathway analysis indicated that DEPs were enriched in pathways such as tight junction, endocytosis, complement, and coagulation cascades. CONCLUSIONS: The nutritional intervention was associated with increased abundance of caseins and certain immune-related proteins and with reduced abundance of lipid metabolism-related proteins. These changes suggest an altered composition of MFGM proteins, with patterns that may be relevant to immunomodulatory (complement activation) and antioxidant (GPX3 upregulation) functions in colostrum. However, direct evidence for effects on calf health outcomes was not obtained, and these interpretations require further validation.