| The aim of this study was to support the theoretical basis and experimental foundation ofadding rumen-protected choline on periparturient dairy cows to improve productionperformance and the health status of diary cows, reduce its negative energy balance, prolongits useful life, expound the effection of different hormones on liver fat metabolism at themolecular level, and provide references for regulation of hepatic lipid metabolism of dairycows.Test one: Sixty Holstein cows with similar parity, age, milk yield and the expectedproduction date was used single factor trial design, were randomly assigned to three groups: I,II, III group each group twenty. I, II, III group of dairy cows in the prenatal15days to15dayspostpartum were fed basal diets, basal diets+20g Rumen-protected choline, basal diets+30gRumen-protected choline,respectively. The results showed as follows:1） Periparturient dairycows diet supplemented with20g Rumen-protected choline can significantly increase milkyield （P＜0.05）, milk fat, milk protein, lactose and total solids had the increasing trend （P＞0.05）. Supplemented with30g Rumen-protected choline can significantly increase milkyield, milk fat, milk protein, total solid（sP＜0.05）, lactose had an increasing trend（P＞0.05）;2） Periparturient dairy cows diet supplemented with20g Rumen-protected choline cansignificantly increase the levels of blood glucose （Glu） and reduce density lipoprotein（LDL）（P＜0.05）, significantly reduce the levels of non-esterified fatty acid （NEFA）,β-hydroxybutyrate acid （BHBA） and total cholesterol （CHO）（P＜0.05）, triglyceride（TG）and total amino acids （T-AA） had the increasing trend （P＞0.05）. Supplementedwith30g Rumen-protected choline can significantly increase the levels of LDL （P＜0.01）,significantly increase the levels of Glu, TG and T-AA（P＜0.05）, significantly reduce thelevels of NEFA, BHBA and CHO （P＜0.01）;3） Periparturient dairy cows dietsupplemented with20g Rumen-protected choline can significantly increase the levels ofinsulin （INS）（P＜0.05）, significantly reduce the levels of glucagon（GC） and leptin（LEP）（P＜0.05）. Supplemented with30g Rumen-protected choline can significantlyincrease the levels of INS（P＜0.01）, significantly reduce the levels of GC and LEP（P＜0.01）. These showed that, diet supplemented Rumen-protected choline can alleviate negative energybalance, regulate fat and energy metabolism, improve production performance of dairy cowsin transition period, the supplementation with a daily dose of30g Rumen-protected cholineper dairy cow is suggested.Test two: Selected a healthy newborn calves, took caudate process of liver immediatelyafter bleeding to death at asepsis, digested liver tissue by cyclic perfusion method to separatehepatocytes, seeded in6-well culture plate. Chose well growth hepatocyte, respectively added1,10,100,1000nmol/L of insulin,1,10,100,1000nmol/L of glucagon,2.5,5.0,10,50ng/mLof Leptin, Set blank control, three replicates for each concentration. Then used Real-time PCRMethod to analysis expression levels of the gene. The results showed as follows: LDLRmRNA expression levels of all test group of insulin were significantly higher than controlgroup（P＜0.01）, but there was no diference between1,10nmol/L added group（P＞0.05）;LDLR mRNA expression level of1000nmol/L glucagon added group were significantlylower than the control group（P＜0.01）,10,100nmol/L added group were lower than thecontrol group（P＜0.05）, and there was on difference between the other groups（P＞0.05）;There were no significant difference between all groups added leptin. This showed that,insulin can promote the LDLR mRNA expression levels, with increasing concentrations ofinsulin, the LDLR mRNA expression levels was strengthened; glucagon can inhibit the LDLRmRNA expression levels, with increasing concentrations of glucagon, inhibition wasstrengthened; leptin had no influence on LDLR mRNA expression levels. |
PDF Full Text Request