Differential Metabolome Between Colostrum And Normal Milk In Dairy Cows And Effects Of Supplementary Yeast Selenium–Based On Metabonomics

Selenium is an indispensable trace element in the body,which has anti-inflammatory,anti-oxidant and immune-enhancing effects.The addition of selenium in the perinatal diet of dairy cows can alleviate the stress response during childbirth,reduce the incidence of diseases such as herd mastitis and metritis,and be able to effectively reduce the number of somatic cells in milk.However,the effects of other components in milk,especially small molecular metabolites,are poorly studied.Therefore,in order to reveal the effect of yeast selenium supplementation in pre-perinatal period on the components of colostrum and lactation metabolites in dairy cows,the following experiments were carried out in this study: Therefore,in order to reveal the changes in the composition of colostrum and normal milk metabolites in dairy cows,and the effect of perinatal feeding of yeast selenium on the metabolic changes of dairy cow milk with prolonged lactation,the following experiment was conducted: 24 body conditions were selected.The healthy perinatal cows with similar scores,parity,age and expected date of birth were randomly divided into the control group(group C)and the experimental group(group T),with 12 heads in each group.Group C was fed a basal diet.In group T,0.15 g/kg dry matter of yeast selenium was added to the basal diet from the 21 st day before the expected date of delivery until the day of delivery.The colostrum and the normal milk were collected within1 hour after delivery of each cow and 21 days after delivery,and the whey was centrifuged according to the No.of the cattle and the group.The samples were divided into C-0d and T-0d(colostrum),C-21 d and T-21d(normal milk)by milk type and bovine grouping.Non-targeted LC-MS metabolic profiling was performed on each group of cow milk using positive and negative modes.For the test results,multivariate statistical analysis and univariate statistical analysis were respectively used for the data of C-0d group and C-21 d group,C-0d group and T-0d group,T-0d group and T-21 d group,C-21 d group and T-21 d group were analyzed to screen differential metabolites in milk between groups,and revealed by bioinformatics analysis the biological pathways involved in differential metabolites.The results of this test are as follows:1.Differences in milk colostrum and normal milk metabolism profiles.There were 97 metabolites in the C-21 d group compared with the C-0d group(P<0.05).The contents of free amino acids and dipeptides were significantly lower(P<0.05);the content of lipids such as linoleic acid,arachidonic acid,phytosphingosine were significantly decreased(P<0.05);the content of lactose content was significantly increased(P<0.05),the content of 6'-sialyllactose were significantly decreased(P<0.05);the contents of nucleotides and their derivatives such as adenosine,uridine and guanosine diphosphate were significantly decreased(P<0.05);the content of citric acid and oxoglutarate were significantly increased(P<0.05).The changes in these metabolites suggest that when the milk of cows is transferred from colostrum to normal milk,the content of essential amino acids,proinflammatory mediators,cell proliferation and differentiation materials supplied to calves gradually decreases,and the energy supply gradually increases.The change is to support the energy sources needed for the early survival and growth of newborn calves.2.The effect of yeast selenium on the colostrum and normal milk metabolism of dairy cows.There were 101 metabolites have happened significant changes between the T-21 d group and the T-0d group(P<0.05).The changes of these metabolites were similar to those of the blank group.Afterwards the effect of adding selenium on the colostrum or normal milk metabolism profile was found.There were 28 significant differential metabolites between the T-0d group colostrum and the C-0d group colostrum(P< 0.05),there were 26 significant differential metabolites between the T-21 d group milk and the C-21 d group milk(P<0.05).After feeding yeast selenium,the content of leucine and phenylalanine in colostrum of dairy cows was significantly increased(P<0.05);the content of sphingosine and thromboxane B2 was significantly decreased(P<0.05);the content of lactose was significantly increased(P<0.05);the contents of deoxyuridine,cyclic guanosine monophosphate and xanthine were significantly decreased(P<0.05);chenodeoxycholic acid and deoxycholate glycine conjugate were significantly increased(P<0.05).Changes in these metabolites suggest that selenium changes the composition of colostrum metabolites in dairy cows.The content of leucine and phenylalanine,energy source lactose and anti-inflammatory metabolites increased,while the content of peptides,pro-inflammatory metabolites and cell proliferation raw materials decreased.After selenium yeast feeding,the content of peptides in cow milk was significantly reduced(P<0.05);the contents ofsphingosine and leukotriene A4 were significantly decreased(P<0.05);The contents of deoxyuridine,guanosine cyclophosphate,xanthine nucleotide were significantly decreased(P<0.05);and the contents of acetoacetic acid and adenosine monophosphate were significantly increased(P<0.05);The content of anserine deoxycholic acid was significantly increased(P<0.05).The changes of these metabolites suggested that selenium changed the composition of milk metabolites in dairy cows,which was mainly manifested as decreased amino acid metabolites,proinflammatory metabolites and cell proliferation raw materials,and increased energy substances.3.The common effect of yeast selenium on the metabolic profile of plasma and colostrum on the day of delivery of the cow.17 significant differential metabolites were identified between the C-0d and T-0d groups(P<0.05).There were only 4 common differential metabolites between 28 differential metabolites in the colostrum of the C-0d groups VS.the T-0d group and 17 differential metabolites in the plasma of the C-0d groups VS.the T-0d group.The content of leucine and phenylalanine in the plasma of T-0d group was lower than that of C-0d group,but the content of milk in T-0d group was higher than that of C-0d group.It is suggested that selenium may promote the absorption of these two amino acids by the mammary gland from plasma and release to colostrum.Conclusion:(1)Dairy colostrum provides amino acids,lipids,sugars and nucleotides for newborn calves,while regular milk provides a large amount of energy substances to participate in the tricarboxylic acid cycle and the pentose phosphate pathway for calves.(2)Feeding selenium in the pre-perinatal period of dairy cows adjusts the milk metabolism profile,increases energy and anti-inflammatory media supply for calves,and reduces the peptides and supply of proinflammatory media.(3)Feeding selenium in the pre-perinatal period of dairy cows may affect the absorption of leucine and phenylalanine from plasma by the mammary gland and release to colostrum.