Polar lipids and proteins in milk fat globule membranes as players in spontaneous lipolysis in cow's milk.

A study of the lipidome and proteome was performed on milk fat globule membranes (MFGM) originating from milk samples from high (HL) and low (LL) lipolysis groups of cows. Combined univariate and multivariate statistical analyses proposed a set of variables highly associated to contrasted samples with regard to milk lipolysis. Milk from HL group were related to 4 phosphatidylinositols, 8 phosphatidylcholines, 1 sphingomyelin and 27 proteins, among them the phosphatidylcholine/phosphatidylethanolamine ratio and ORM1 may contribute to the membrane remodeling of the MFGM. The abundance of CP, CHI3L1, NECTIN2, A2M were strongly positively correlated with HL. Conversely, 3 phosphatidylinositols, 1 phosphatidylcholine and 2 phosphatidylethanolamines were assigned to the LL group. The HL group in cows is associated with a specific MFGM phospholipids and proteins profile, suggesting an impact on membrane fluidity and lipid rafts composition intervening in LPL anchoring and activation, as well as on pro-inflammatory lipids and proteins.