Proteome of milk fat globule membrane and mammary gland tissue in goat fed different lipid supplementation

This study was conducted to assess the effect of lipid supplementation on the proteomic profile of milk fat globule membrane (MFGM) and mammary gland tissue (MGT) in lactating goats. Thirty-eight crossbred goats received a total mixed ration (TMR) based on chopped elephant grass and concentrate during 35 days post-partum. They were divided into three diet groups two weeks after kidding, namely, Control group (CG; n = 12), fed baseline TMR; Flaxseed group (FG; n = 13), fed ground flaxseed added to the TMR for 21 days (12 % total dry matter); and microalgae Chlorella group (MCG; n = 13), fed microalgae Chlorella added to the TMR for 21 days (0.05 % live weight). Blood plasma concentrations of total protein, albumin, and glutathione peroxidase were determined. Weekly milk samples were used to estimate milk yield and protein and fat levels. MGT samples were biopsied on the 35th day of the experiment. The protein profile of MFGM and MGT was assessed using 1D SDS-PAGE and mass spectrometry. The MCG group showed lower dry matter intake and higher milk fat than the other diets. The milk protein level was not affected by the diet group. The 22 protein bands identified in MFGM showed no difference between diets. The multivariate model selected eight protein bands (VIP > 1) to segregate the diet groups. Nine out of 44 protein bands identified in MGT showed lower expression in the FG group, which had a lipid level of the diet of 8 %. The multivariate model involved 11 band proteins (VIP > 1) in the diet group segregation. Thus, the increased lipid level in the diet or milk of lactating goats had no marked effects on the MFGM proteome. High lipid diet interfered with the expression of proteins in the mammary glands, which points to the greater sensitivity of this organ to the effort of lipotoxicity.

Automated summary

The study found that increasing lipid levels in the diet or milk of lactating goats had no significant effect on the MFGM proteome, while a high-fat diet interfered with protein expression in the mammary glands, indicating the organ's greater sensitivity to lipotoxicity.