Astral-data-independent acquisition depicts the dynamic landscape of milk fat globule membrane proteins in yak colostrum, transitional milk, and mature milk

The MFGM proteins are crucial for neonatal growth, immune regulation, and metabolic balance throughout mammalian life cycle. However, the composition and dynamic changes of MFGM proteins in yak colostrum (MC), transitional milk (MT), and mature milk (MM) remain poorly understood. This study applied Astral-data-independent acquisition proteomics to profile yak MFGM proteins, identifying 5,590 proteins. Specifically, 2,310 MFGM proteins were significantly differentially expressed between MC and MM, 2,351 between MC and MT, and 846 between MT and MM. In MC, proteins involved in immune modulation, antioxidants, and cell protection were highly expressed. As lactation progressed, lipid metabolism proteins increased, particularly in MT, which demonstrated activation of metabolic pathways related to triglyceride synthesis and fatty acid desaturation. Our findings reveal that MFGM proteins support passive immunity in MC, activate metabolism in MT, and ensure sustained nutrient delivery in MM. These insights are valuable for developing yak milk-based dairy products.