Effects Of Isopropyl Methionine Hydroxy Analogue On Blood Indexes And Metabonomics Of Cows During Perinatal Period

The perinatal period is the most important stage in the entire lactation cycle of dairy cows,and it is also easy to cause disorder in physiological function and metabolism.Studies have shown that adding methionine(Met)can improve the oxidative stress state of livestock and poultry,and improve their immunity.Methionine hydroxy analogue isopropyl ester(2-hydroxy-4-(methylthio)butanoic acid isopropyl ester,HMBi)is a rumen bypass methionine that can be effectively absorbed by ruminants.In this experiment,HMBi was added to diets of dairy cows during the pre-perinatal period to study its effects on blood biochemical indicators,immune indicators,antioxidant indicators and blood metabolomics of dairy cows,and to explore its mechanism of action.It will provide a theoretical basis for the application of hmbi in dairy cows during perinatal period.1.The effect of adding isopropyl methionine hydroxy analogue on the blood indexes and immune function of dairy cows during pre-perinatal period.Compared with the control group,the total plasma protein(TP)of the dairy cows in the experimental group increased significantly(P<0.05),and the concentration of alanine aminotransferase(ALT)and aspartate aminotransferase(AST)decreased significantly at 7 days postpartum in the experimental group:7 days before delivery and 7 days after delivery Plasma urea nitrogen(BUN)andβ-hydroxybutyric acid(BHBA)concentrations tend to decrease(P>0.05);the test group plasma immunoglobulin-G(IgG),tumor necrosis factor-α(TNF-α),white blood cells The concentration of interleukin-2(IL-2)did not change significantly(P>0.05);the total antioxidant capacity(T-AOC)and glutathione peroxidase(GSH-PX)of the test group were 7 days before and 7 days after delivery.)And the concentration of superoxide dismutase(SOD)have an increasing trend,and the concentration of malondialdehyde(MDA)has a decreasing trend(P>0.05).It shows that adding 30 g/d HMBi to the pre-perinatal diet can improve the protein metabolism of dairy cows in the perinatal period,improve the state of inflammation and oxidative stress,and enhance their antioxidant capacity.2.The effect of adding isopropyl methionine hydroxy analogue on the plasma metabolites of dairy cows during the pre-perinatal periodThe experimental group and the control group were screened out a total of 7 significantly different metabolites(3 up-regulated and 4 down-regulated).In the positive ion mode,the plasma content of the experimental group was significantly increased,including cis 4-hydroxy-D-proline and L-histidine,the substances significantly reduced are phenylacetic acid and piperonic acid(P<0.05).In the negative ion mode,creatine was significantly increased in the test group’s plasma,and aminocaproic acid and L-fucose were significantly decreased(P<0.05).Enrichment analysis of different metabolites through participating metabolic pathways revealed that arginine and proline metabolism,lysine degradation,histidine metabolism,amino sugar and nucleotide sugar metabolism,fructose and mannose metabolism pathways The related metabolites have changed significantly.It shows that the addition of 30 g/d HMBi in the perinatal period may relieve the negative balance of energy and protein in the perinatal period by adjusting the level of amino acid and sugar metabolism in dairy cows,and improve the immune and antioxidant functions of dairy cows.In summary,adding 30 g/d HMBi to the pre-perinatal diet can improve the inflammation and oxidative stress state of the perinatal dairy cows,and enhance their antioxidant capacity.The mechanism may be related to the addition of HMBi to regulate amino acid and sugar metabolism in the body.