Changes Of Rumen Fluid Metabolome,Blood Biochemical Indexes And Inflammatory Factors In Postpartum Dairy Cows

The perinatal period refers to 3 weeks before delivery to 3 weeks after delivery.In this period,especially in the later stage,because of the rapid decline in dry matter intake and the rapid increase in milk production,the dairy cows is easily caught negative energy balance so that metabolism and inflammatory diseases is often occur.According to statistics,about 75%of diseases(including infectious diseases and metabolic diseases)occur in dairy cows after birth.The current researches show that changes in the rumen microbiota is closely related to negative energy balance,postpartum metabolic and inflammatory diseases.Therefore,this experiment studied the changes in rumen metabolites,blood biochemical indicators and inflammatory factors of dairy cows at different stages of postpartum to reveal the nosogenesis of negative energy balance and the related diseases with it in postpartum cows from the perspective of the digestion of rumen microorganism to feed.The results are as follows:1.The results of UPLC-MS/MS rumen fluid metabolomics:9 metabolic pathways were significantly changed due to 73 metabolites were up-regulated and 48 metabolites down-regulated at 7 days postpartum;16 metabolic pathways were obvious altered due to 141 metabolites were up-regulated and 36 metabolites down-regulated at 14 days postpartum;7 metabolic pathways were strikingly varied due to 115 metabolites were up-regulated and 32 down-regulated at 21 days postpartum,These altered pathways were mainly involved in carbohydrate metabolism,amino acid biosynthesis and metabolism,nitrogen-containing compound metabolism,lipid metabolism,rumen microbial secondary metabolite biosynthesis and vitamin B6 metabolism.Of which the activities of tyrosine metabolism,tryptophan metabolism,amino acid biosynthesis,pyrimidine metabolism and purine metabolism significantly increased at each stage.2.The results of blood biochemical indexes at Od,7d,14d and 2 1d postpartum:The blood concentrations of AST,GGT,ApoB and HDL-C at 7d,14d and 21d postpartum were all significantly higher than those at Od postpartum(P<0.05),while the blood concentrations of ALP TG and GLu were significantly lower than those at 0 d postpartum(P<0.05);The blood concentrations of GLB and LDL-C at 7d postpartum were significantly higher than those at other stages(P<0.05);The blood concentrations of BHBA and TCH at 14d postpartum were significantly higher than those at other stages(P<0.05),but the blood concentrations of NEFA and ApoAl were significantly lower than those at other stages(P<0.05);TP concentration in blood after 21 days was significantly higher than that at other stages(P<0.05),but VLDL blood concentration was significantly lower than that at 7d postpartum(P<0.05);The blood concentrations of ALT and ALB were no significant difference among all stages(P>0.05).3.The results of blood inflammatory factors at Od,7d,14d and 2 1d postpartum:The blood concentrations of TNF-α,TGF-β,IgG,IL-2,IL-4,IL-8,IL-10,IL-10 at Od postpartum were significantly higer than those at 7d,14d and 21 d postpartum(P<0.05),among the factors,IL-17 and IL-18 blood concentrations exhibited a significant decreasing trend with the increase in postpartum days(P<0.05),and IL-13 blood concentration was significantly higher at 14d postpartum than that at 7d and 21d postpartum(P<0.05);IL-23 blood concentration increased significantly with the gradually increase in postpartum days(P<0.05);IL-1 concentration was postpartum 14d was significantly higher than other time periods(P<0.05),while IL-6 postpartum 21d was significantly lower than other time periods(P<0.05).Conclusion:During the perinatal period of 21 days postpartum,the carbohydrate metabolism,amino acid biosynthesis and metabolism,nitrogen-containing compound metabolism,lipid metabolism,rumen microbial secondary metabolite biosynthesis,and vitamin B6 metabolism were significantly changed,among which amino acid biosynthesis,some amino acid metabolism,and nitrogen-containing compound metabolism were significantly increased in all postpartum stages.Except for the ALT and ALB blood concentrations,the other biochemical indicators were changed with varying degrees,suggesting that the fat metabolism and liver function changed significantly in postpartum dairy cows;Most of the inflammatory factors at Od postpartum were higher than that at 7d,14d,and 21d postpartum,suggesting that the dairy cows experienced various degree of inflammatory responses within 7 days postpartum.