Candidate Biomarkers For Different Reproductive Status Of Cows After Artificial Insemination Were Selected Based On Metabolomics Techniques

The establishment of dairy cow pregnancy is an extremely complicated process.Identifying the pregnancy status of dairy cows as early as possible after artificial insemination have great significance for improving pasture fecundity and reducing breeding costs.This study is based on the UHPLC-QTOF-MS non-targeted metabonomics technology.The pregnant group,the non-pregnant group and the return-to-estrus group(12 heads per group)after artificial insemination were analyzed at different time points in the early mating stage(the day of artificial insemination(group A),5 days(group B),17 days(group C)and 28 days(group D))plasma metabolic profile and metabolite changes were studied.Principal component analysis(PCA)and orthogonal partial least squares-discriminant analysis(OPLS-DA)showed that the plasma metabolic profile of the pregnant group,the non-pregnant group and the return-to-estrus group significantly changed.(1)In pregnant group,the synthesis of glycine,serine and threonine and the metabolic pathways of glyoxylic acid and tricarboxylic acid in pregnant cows were changed on the day of insemination compared with the 28 days,the histidine metabolic pathway changed on the 5 days of insemination compared with the 28 days.Hexanoic acid,beta-homoproline,1-methylguanosine were expected to be candidate biomarkers for plasma metabolite changes of pregnant cows at the 5 days of insemination.Argininosuccinic acid was expected to be candidate biomarkers for plasma metabolite changes of pregnant cows at the 17 days of insemination.Pyrrole-2-carboxylic acid,1-palmitoylcamitine,met-tyr,phe-tyr,arg-thr and val-val were expected to be candidate biomarkers for plasma metabolite changes of pregnant cows at the 28 days of insemination.(2)In non-pregnant group,lumichrome and dl-vanillylmandelic acid were expected to be candidate biomarkers for plasma metabolite changes of non-pregnant cows at the 5 days of insemination.Trp-glu,lle-arg,glycodeoxycholic acid and 2-ethoxyethanol were expected to be candidate biomarkers for plasma metabolite changes of non-pregnant cows at the 17 days of insemination.(3)In return-to-estrus group,metabolic pathways of glycine,serine and threonine,histidine metabolism and glyoxylic acid and tricarboxylic acid metabolism were changed on the day of insemination compared with the 28 days.Quinate,val-asp,gly-arg,EDTA,5’-deoxyadenosine,3-methylhistidine and gamma.-L-Glu-.epsilon.-L-Lys were expected to be candidate biomarkers for plasma metabolite changes of return-to-estrus cows at the 28 days of insemination.(4)Arginine bianabolism was changed in pregnant,non-pregnant and return-to-estrus group on the 17 days of artificial insemination compared with the day of artificial insemination.Allocystathionine and argininosuccinic acid also changed.Ala-leu changed was observed in the pregnant,non-pregnant and return-to-estrus group on the 28 days of artificial insemination compared with the day of artificial insemination.In conclusion,metabolic pathways have changed in different reproductive states after artificial insemination of dairy cows.These metabolites were expected to be candidate biomarkers for different stages of different reproductive states after artificial insemination,which lay a foundation for the study of blood metabolites changes and embryo death under different reproductive status at early stage after mating.