Plasma Metabolomics Analysis Of Subclinical Vitamin E Deficiency In Dairy Cows During Early Lactation

Cows durig the transition are mostly in a state of negative energy balance due to production stress and lactation stress.Cows lack a variety of nutrients and the declined immunity leads to a variety of diseases.At this stage,it is very critical to meet the nutritional needs of dairy cows.Vitamin E is an important broken chain antioxidant,which can eliminate lipid peroxidation products by inhibiting the peroxidation reaction of polyunsaturated fatty acids in cell membranes and lipoproteins,thus protect the structural integrity of cell membranes.It also can enhance the immunity and improve the reproductive performance of dairy cows.However,because vitamin E is a fat-soluble vitamin and lacks rapid early detection methods,it is difficult to detect vitamin E deficiency in time This makes dairy cows prone to immunosuppression and oxidative stress and the resulting diseases during the perinatal period and early lactation,which has now become a major problem that harms the health of dairy cows.Therefore,this study applied the combined techniques of LC / MS and NMR in metabolomics to detect plasma samples of vitamin E subclinical deficiency cows and healthy cows,explore the metabolic spectrum and characteristic biomarkers of vitamin E subclinical deficiency,which will provide a theoretical foundation for the early monitoring and prevention of vitamin E subclinical deficiency in dairy cows.The experiment was carried out in an intensive cattle farm in heilongjiang province.High-yielding cows with similar background information such as age,litter and body condition were randomly selected as experimental animal.According to the plasma vitamin E content from the day of delivery to 30 days after delivery,the cows were divided into the subclinical vitamin E deficiency group(vitamin E:2~3 g/m L)and the normal group(vitamin E > 4 g/m L)with 40 heads per group.Then according to the detection of blood biochemical indicators and disease information,14 cows with the smallest differences in energy metabolism,liver function,vitamins,oxidative stress and other indicators were selected for each group for the LC/MS and NMR analaysis,combined with multivariate statistical analysis and bioinformatics analysis to screen out the differential metabolites of vitamin E subclinical deficiency,and study relationship and role of differential metabolites and subclinical deficiency of vitamin E in dairy cows.IVThe results showed that:(1)NEFA,AST,MDA,LDL,CEHE in plasma of dairy cows with vitamin E subclinical deficiency increased significantly(p<0.05),ALB,T-AOC,HDL decreased significantly(p<0.05),indicating that dairy cows with vitamin E subclinical deficiency have typycally hemopathological features such as negative energy balance,type 2 ketosis,oxidative stress and liver injury.(2)30 plasma differential metabolites of dairy cows with vitamin E subclinical deficiency were obtained by 1H-NMR technology,all of which were elevated.They were lactic acid,glutamic acid,glycine,citric acid,pyruvic acid,phosphorylcholine,LDL,acetone,3-hydroxybutyric acid,?-glucose,and ?-glucose,which mainly involved in alanine,aspartic acid and glutamic acid metabolism,glycolysis or gluconeogenesis,citrate cycle(TCA cycle),pentose phosphate pathway,glutathione metabolism,glycine,serine and threonine metabolism and other metabolism.(3)By using LC/MS technology,17 plasma differential metabolites were obtained in dairy cows with vitamin E deficiency,among them 3 reduced metabolites were formylanthranilic acid,tetradecanoic acid and phenylpyruvate,the 14 increased metabolites were Xylulose,xylitol,and glucuronic acid that involve in sugar metabolism;and phosphat-idylethanolamine,phosphatidylcholine,1-acyl-sn-glycerol-3-phosphocholine,sphingo-myelin,4-D-Hydroxysphinganine,L-palmitoylcarnitine,(15Z)-tetraenoic acid,(9Z)-octadecenoic acid and tetradecanoic acid and hydroxyproline,D-serine that involve in lipid metabolism;and hydroxyproline,d-serine,formylanthranilic acid,and phenylpyruvic acid that involve in amino acid metabolism.Their main metabolic pathways are glycerophospholipid metabolism,sphingolipid metabolism,linoleic acid metabolism,interconversion of pentose and glucuronate,starch and sucrose metabolism,glycine,serine and threonine metabolism,phenylalanine,tyrosine and tryptophan biosynthesis,arachidonic acid metabolism,fatty acid metabolism,phenylalanine metabolism,etc.(4)The analysis of metabolites and metabolic pathways of the two groups showed that the lack of VE in dairy cows was related to negative energy balance,type 2 ketosis,oxidative stress and liver injury.Conclusion:in this study an combination of LC/MS and NMR is used to obtain 47 differential metabolites in plasma of cows with VE sublinical deficiency,and panoramically illuminate metabolic changes such as sugars,lipids and amino acids in periparturient cows with VE subclinical deficiency.It lays a foundation for further research on the etiology and new prevention and treatment strategies of VE subclinical deficiency in transition period of dairy cows.