Evaluation Of The Health-care Effect Of Myricetin Mixed Granules On Energy Metabolism Disorders In Periparturient Dairy Cow

Ketosis and fatty liver,which are mainly energy metabolism disorders,are a common type of high-incidence group disease in dairy cows on large-scale pastures,causing serious economic losses to the dairy industry.The research and development of efficient prevention and control products for such diseases has become a research hotspots in the field.The purpose of this experiment is to develop a health care granule with myricetin as a functional ingredient,and to elucidate the mechanism of myricetin regulating high fatty acid-mediated lipid damage in calf hepatocytes by evaluating its prevention and control effect on energy metabolism disorders in dairy cows,and to provide new products and technical support for disease prevention and control.In this experiment,palm oil,corn oil,myricetin,phytosterol,soybean isoflavones and other materials were mixed in proportion to prepare a postpartum health care granule.In a large-scale pasture in Heilongjiang Province,18 healthy dairy cows were randomly selected in the perinatal period,9 in the control group and 9 in the experimental group（40g/day/head）,were continuously fed for 7 days on the day of parturition,and all the experimental cows were collected blood,urine and postpartum milk to detect relevant metabolic indicators in blood,urine and milk.In order to explore the effect of myricetin,the main functional component of the prepared postpartum health care granules,on the lipid metabolism of hepatocytes,in this experiment,primary calf hepatocytes were isolated in vitro,and 1.2 m M fatty acid was added to build a primary calf hepatocyte hepatic lipid deposition model.Different concentrations of myricetin were added respectively,and the levels of triglycerides,lipid droplets,and oxidation and antioxidant indexes in hepatocytes were detected,Western Blotting and q RT-PCR were used to detect lipid metabolism,endoplasmic reticulum stress levels and inflammatory factors,in order to explore the regulatory effect of myricetin,the main component of myricetin mixed granules on the lipid metabolism in hepatocytes.The results of the in vivo study showed that the incidence of ketosis in the experimental group was 33%lower than that of the control group,the risk of fatty liver was reduced by 22%,and the economic losses were reduced by 80.6 and 120.9 yuan/head respectively.Compared with the control group,there was no significant difference in the prenatal blood biochemical indexes of dairy cows in the experimental group;the levels of AST,AST/ALT,TBIL,GGT,LDH,GLO,NEFA and BHBA in the experimental group were significantly or extremely significantly lower than those in the control group at 3rd,7th,14th,and 21st days postpartum（P<0.05）,while A/G and GLU levels were significantly increased（P<0.05）.In the milk indicators,the daily milk yield of the experimental group was lower than that of the control group on the 0-9 d postpartum,but increased on the 10-21 d postpartum;the milk fat of the cows in the experimental group was significantly lower than that of the control group on the 21st postpartum（P<0.05）;lactose at 21st postpartum was significantly higher than that in the control group.In the results of urine fractionation,the levels of KET,WBC and VC in the experimental group decreased significantly after delivery,while the p H of urine increased significantly at 14th days after delivery（P<0.05）.In addition,the blood MDA of the experimental group was significantly lower than that of the control group after delivery（P<0.05）;while SOD and GSH were increased to different degrees after delivery（P<0.05）.The above shows that the postpartum health granules prepared in this experiment can significantly alleviate liver damage,improve antioxidant capacity and lactation performance,and ultimately reduce the incidence of energy metabolism diseases in dairy cows and reduce the economic loss of pastures.The results of in vitro experiments showed that the addition of 1.2 m M FAs up-regulated the expression of FASN,ACC1,SREBF1 and DGAT1 in hepatocyte lipid synthesis genes,and significantly increased the content of TAG and lipid droplets（P<0.05）;endoplasmic The expressions of network stress-related proteins GRP78,PERK and inflammatory pathways NF-κB and TNF-α,as well as oxidative stress indicators MDA and H₂O₂were significantly increased（P<0.05）.After adding myricetin,the main component of postpartum health care granules（25,50,100μM）,compared with the group adding 1.2 m M FAs,adding 50 or 100μM myricetin significantly reduced the content of TAG and lipid droplets（P<0.01）.At the same time,the expressions of lipid synthesis-related genes SREBF1 and FASN were decreased;the oxidative stress indexes of MDA and H₂O₂,the expressions of endoplasmic reticulum stress-related proteins PERK,GRP78,and inflammatory pathways NF-κB and TNF-αwere down-regulated（P<0.05）;in addition,the results showed that the addition of 50μM or 100μM of myricetin was consistent with the addition of antioxidants NAC to high fatty acid-induced lipid damage in hepatocytes,this suggests that myricetin may alleviate the oxidative damage and endoplasmic reticulum stress pathway of hepatocytes induced by high concentrations of fatty acids through antioxidant effects,down-regulate the expression of inflammatory pathway NF-κB,and then reduce the production and accumulation of adipose in hepatocytes.In conclusion,the myricetin mixed granules prepared in this experiment can significantly alleviate liver injury and reduce the occurrence of energy metabolism disorders in perinatal dairy cows to a certain extent.Its functional component,myricetin,downregulates the expression of endoplasmic reticulum stress and inflammatory pathways through antioxidant effects,and relieves the accumulation of hepatic lipids.It provides a theoretical basis for postpartum health care measures in large-scale pastures,and has potential health care functions for fatty liver and related metabolic disorders.