| In the production process,to dairy cattle fed high concentrate diets fed to meet the energy requirements of lactating animal model has become a popular trend.But the dairy intake of high concentrate diets can lead to volatile fatty acid deposition in the rumen and increased the release of abnormal metabolites of lipopolysaccharide in the rumen fluid.Furthermore,LPS can transfer into the blood and enter the liver through the portal vein,thus affecting the gene expression and redistribution of nutrients in the liver.However,the specific pathways and mechanisms are still unclear.In this study,Guanzhong dairy goat was used as an animal model to simulate feeding patterns in actual production.Through the method of feeding in the diets added a high proportion of fine,the purpose was to reveal the effects of long term feeding of high concentrate diets on blood biochemical indexes and liver glucose and lipid metabolism in Guanzhong dairy goats,and provide a theoretical basis for scientific breeding of lactating dairy goat.The research contents and results are as follows:In this study,14 heads of similar weight,good health,early lactation in 2 ~ 3 pregnancies of Guanzhong dairy goats were selected and reared in Shaanxi Yang Ling Northwest Agriculture and Forestry University ranch.14 head of dairy goats randomly divided into two groups: the control group was 6 and fed diets with concentrate-to-forage ratios of 35:65,and the experimental group was 8 and fed diets with concentrate-to-forage ratios of 65:35.The experiment lasted for 19 weeks.During the test period,all the animals were allowed to drink water freely and daily activities two times.1.Taking the jugular venous blood to determine the blood biochemical parameters,the results show that the concentration of glutamic-pyruvic transaminase was up-regulated significantly(P < 0.05)and triglyceride has a tendency to decrease(P = 0.099)in blood of dairy goats fed high-concentrate diets in experiment group.However,in the long-term feeding of high concentrate diet,the majority of biochemical indicators in the blood did not change significantly(P > 0.05).2.By the classical HE staining,the results showed that high concentrate diets can cause dairy goat hepatocytes highly swelling,larger size,cytoplasm dissolved.And the hepatic cells showed swelling degeneration or vacuolar degeneration.3.By Real-time PCR to detect liver lipid metabolism related genes expression,the results showed that the expression of the lipid metabolism and anabolism related gene of dairy goat for long-term feeding of high concentrate diets were not changed significantly(P > 0.05).Although,under the condition of the long term feeding of high concentrate diet,the expression of the lipid metabolism related genes LPL,SCD,FADS2 mRNA increased,but did not reach a significant level.4.By Real-time PCR to detect hepatic gluconeogenesis related genes expression,the results showed that the expression of hepatic gluconeogenesis key genes PEPCK-c and Fbp1 mRNA decreased significantly(P < 0.05),indicating that high concentrate diets inhibited liver gluconeogenesis.5.Western blot showed that the expression of Fbp1 protein decreased significantly(P < 0.05);however,the enzyme activity of Fbp1 increased significantly(P < 0.05).6.Liver transcription related gene expression was detected by Real-time PCR,and the results showed that the experimental group of goat liver X receptor(Liver X-activated,receptor,LXR)and retinol X receptor gamma(Retinoid X receptor,RXRγ)gene expression of mRNA was significantly decreased(P < 0.05).The results of this study show that long-term feeding of high-concentrate diets can lead to increased blood glutamic-pyruvic transaminase,suggesting that this may be related to liver cell damage,but the expression of genes related to lipid metabolism were not significantly changed.The inhibition of hepatic gluconeogenesis may be caused by hepatocyte damage,thereby inhibiting the expression of transcription related genes in the liver. |
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