Comparative Proteomic Analysis of Milk Fat Globule Membrane Proteins between Donkey Colostrum and Mature Milk

To elucidate the differential milk fat globule membrane (MFGM) proteins between donkey colostrum (DC) and mature milk (DM), a comparative analysis was performed using proteomics. A total of 216 and 215 MFGM proteins were characterized in DC and DM, respectively. Among them, 15 differentially expressed and 25 specifically expressed MFGM proteins were identified. Bioinformatics analysis showed that the significantly differentially expressed MFGM proteins were mainly involved in cellular components including extracellular exosome, extracellular vesicle, and extracellular organelle compartments, and participated in biological processes such as external stimuli, cell proliferation, and blood vessel morphogenesis, and molecular functions such as metal ion binding, cation binding, and calcium ion binding. Additionally, these significantly differentially expressed MFGM proteins were mainly involved in metabolic pathways such as the complement and coagulation cascades and intestinal immune network for IgA production. Furthermore, some key protein factors with high connectivity, as determined by protein network interaction analysis, were identified as differently expressed MFGM proteins. This study provides a better understanding of the biological properties of donkey MFGM proteins and paves the way for future research of MFGM protein nutrition and for the development of formula milk powder.