Milk fat content and DGAT1 genotype determine lipid composition of the milk fat globule membrane

• Published in: PloS one 2013-07, Vol.8 (7), p.e68707-e68707
• Main Authors: Argov-Argaman, Nurit, Mida, Kfir, Cohen, Bat-Chen, Visker, Marleen, Hettinga, Kasper
• Format: Article
• Language: English
• Subjects: acids; Acyltransferase; Agriculture; Animal husbandry; Animal lactation; Animal sciences; Animals; Biological activity; Biological effects; Biology; Biomarkers - metabolism; Breeding; Breeding - methods; Cattle; Dairy cattle; Dairy products; Dairying - methods; Diacylglycerol O-Acyltransferase - genetics; Diet; Diglycerides; E coli; Endoplasmic reticulum; Enzymes; Escherichia coli; Fatty acid composition; Fatty acids; Female; Food; Genomics; Genotype & phenotype; Globules; Glycolipids - chemistry; Glycoproteins - chemistry; Goats; lactation; Lipid composition; Lipids; mammary-gland; Membrane Lipids - analysis; Metabolism; Milk; Milk - chemistry; Milk fat globule membranes; Oils & fats; parameters; Phosphatase; Phosphatidylethanolamine; Phosphatidylinositol; Phosphatidylserine; Phospholipids; Phospholipids - metabolism; Polymorphism; Polymorphism, Genetic; raw-milk; Rodents; Secretion; Selective breeding; size; Sphingomyelin; Triglycerides - metabolism
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0068707

During secretion of milk fat globules, triacylglycerol (TAG) droplets are enveloped by a phospholipid (PL) trilayer. Globule size has been found to be related to polar lipid composition and fat content, and milk fat content and fatty acid composition have been associated with the diacylglycerol acyltransferase 1 (DGAT1) K232A polymorphism; however, the association between the DGAT1 polymorphism and fat globule size and polar lipid composition has not been studied. The ratio between polar and neutral lipids as well as the composition of the polar lipids in milk has industrial as well as nutritional and health implications. Understanding phenotypic and genotypic factors influencing these parameters could contribute to improving milk lipid composition for dairy products. The focus of the present study was to determine the effect of both fat content and DGAT1 polymorphism on PL/TAG ratio, as a marker for milk fat globule size, and detailed PL composition. Milk samples were selected from 200 cows such that there were equal numbers of samples for the different fat contents as well as per DGAT1 genotype. Samples were analyzed for neutral and polar lipid concentration and composition. PL/TAG ratio was significantly associated with both fat content and DGAT1 genotype. Phosphatidylinositol and phosphatidylserine concentrations were associated with fat content*DGAT1 genotype with a stronger association for the AA than the KK genotype. Sphingomyelin concentration tended to interact with fat content*DGAT1 genotype. Phosphatidylethanolamine (PE) concentration showed a biphasic response to fat content, suggesting that multiple biological processes influence its concentration. These results provide a new direction for controlling polar lipid concentration and composition in milk through selective breeding of cows.