Differential Proteomics Of Protein And Milk Fat Globular Membrane In Different Lactation Stages Of Horses

The purpose of this study was to study the expression of horse milk protein and milk fat globule membrane(MFGM)protein in different lactation stages,revealed the proteomic spectrum and potential biological functions of specific lactation stages,enriched and improved the database of horse milk proteomics,and provided theoretical basis for foal feeding and feed product development.Twelve healthy purebred mares with an average weight of 450-500 kg and about 5 years old were selected as experimental animals.Label-free quantitative proteomics combined with liquid chromatography-mass spectrometry was used for postpartum 1,10,30,60 and 150 d milk protein and MFGM protein differentially expressed protein were analyzed.Before the test,each 12 samples(1,10,30,60 and 150 d)were divided into 3 groups,and 4 milk samples from each group at the same time point were mixed,and the test process was subjected to 3 biological replicates.(1)A total of 51 differential proteins were quantified by studying horse milk proteins in different lactation periods.These 51 differential proteins were annotated by Gene Ontology(GO),and it was found that these differential proteins were mainly single biological processes,biological regulation,multicellular biological processes and stimulus responses in terms of biological processes.It involved extracellular regions,extracellular spaces,capsules and extracellular bodies in terms of cellular components.It included binding activities,endopeptidase regulatory activities and antioxidant activities in terms of molecular functions.Kyoto Encyclopedia of Genes and Genomes(Kyoto Encyclopedia of Genes and Genomes,KEGG)pathway analysis showed that most differential milk proteins were involved in the complement and coagulation cascade and the pathway of Staphylococcus aureus infection.(2)The MFGM protein of horse milk in different lactation periods was studied,and a total of 568 differential proteins were quantified.These 568 differential proteins were annotated with gene ontology and found that these differential proteins were mainly localization,protein metabolism process,transportation and stimulus response in biological processes.It involved membranes,extracellular regions,vesicles and inner membrane systems in terms of molecular functions.It included catalytic activity,binding activity,structural molecular activity and antioxidant activity in terms of cell components.KEGG pathway analysis showed that most of the differential MFGM proteins were involved in ribosomes,protein processing in the endoplasmic reticulum,fatty acid biosynthesis,phagosomes and tight junction pathways.This research provides a new idea for in-depth understanding of the function of horse milk protein,and provides a scientific basis for the production of functional infant formula milk powder close to breast milk.