Effect of the DGAT1 K232A genotype of dairy cows on the milk metabolome and proteome
Lu, J. ; Boeren, S. ; Hooijdonk, A.C.M. van; Vervoort, J.J.M. ; Hettinga, K.A. - \ 2015
Journal of Dairy Science 98 (2015)5. - ISSN 0022-0302 - p. 3460 - 3469.
h-1-nmr spectroscopy - sample preparation - identification - stomatin - membrane - proteins - gene - cattle - yield
Diglyceride O-acyltransferase 1 (DGAT1) is the enzyme that catalyzes the synthesis of triglycerides from diglycerides and acyl-coenzyme A. The DGAT1 K232A polymorphism was previously shown to have a significant influence on bovine milk production characteristics (milk yield, protein content, fat content, and fatty acid composition). The mechanism of this influence has, however, not been elucidated. In this study, metabolomics (1H-nuclear magnetic resonance) and proteomics (laser chromatography-tandem mass spectrometry) were applied to determine the serum and lipid metabolite composition and milk fat globule membrane proteome of milk samples from cows with the DGAT1 KK and AA genotypes. The milk samples from cows with the DGAT1 KK genotype contained more stomatin, sphingomyelin, choline, and carnitine, and less citrate, creatine or phosphocreatine, glycerol-phosphocholine, mannose-like sugar, acetyl sugar phosphate, uridine diphosphate (UDP)-related sugar, and orotic acid compared with milk samples from cows with the DGAT1 AA genotype. Based on these results, we propose that the differences between the DGAT1 genotypes may be related to stomatin-sphingomyelin lipid rafts as well as structural (cell membrane) differences in epithelial cells of the mammary gland. In conclusion, our study shows that, in addition to previously described changes in triglyceride composition, cows differing in DGAT1 polymorphism differ in their milk proteome and metabolome, which may help in further understanding the effect of the DGAT1 K232A polymorphism on milk production characteristics.
Changes in milk proteome and metabolome associated with dry period length, energy balance and lactation stage in post parturient dairy cows
Lu, J. ; Antunes Fernandes, E.C. ; Páez Cano, A.E. ; Vinitwatanakhun, J. ; Boeren, S. ; Hooijdonk, A.C.M. van; Knegsel, A.T.M. van; Vervoort, J. ; Hettinga, K.A. - \ 2013
Journal of Proteome Research 12 (2013)7. - ISSN 1535-3893 - p. 3288 - 3296.
mouse mammary-gland - epithelial-cells - fatty-acids - inflammatory response - beta-hydroxybutyrate - ketone-bodies - liver - apoptosis - stomatin - health
The early lactation period of dairy cows, which produce high quantities of milk, is normally characterized by an insufficient energy intake to cover milk production and maintenance requirements. Mobilization of body reserves occurs to compensate this negative energy balance (NEB), and probably as a consequence there is a higher susceptibility to diseases and metabolic disorders. There are several diagnostic methods to detect NEB, usually involving ketosis related parameters. Due to the easy availability of milk this is a preferred matrix, but simple and robust predictors of NEB level are missing. To better understand the physiological mechanism of NEB, milk of cows subjected to different dry period lengths, in different energy balance status and lactation stage, were analyzed by untargeted metabolomics and proteomics techniques. Milk of cows in severe NEB showed higher concentrations of acute phase response proteins, unsaturated fatty acids, and galactose-1-phosphate. Improved energy balance (EB) resulted in higher concentration of cholesterol, cholesterol synthesis related proteins, and stomatin. The presence of stomatin and galactose-1-phosphate in milk was strongly dependent on the EB of the cows. These novel and interesting findings warrant more in-depth research to assess their applicability as robust indicators of NEB in milk and to clarify the role of stomatin and galactose-1-phophate in milk of dairy cows in NEB.