| The objective of the current study was to investigate the effects of the compound buffers(sodium bicarbonate,magnesium hydride and sodium butyrate)on the fatty acid metabolism in the rumen and liver and the related gene and protein expression in the liver in mid-lactating goats fed a high concentrate diet.8(body weight 38±3 kg)mid-lactating goats installed ruminal cannula,portal and hepatic vein catheters were used as experimental animal.The total experimental period was 5 months,and the pretest lasted for 7 days.The experiment included 4 parts.Experiment 1:The aim of this study was to assess the effects of the compound buffers on thepH value and concentrations of VFAs inrumen fluid and the metabolism of VFAs inthe liver ofmid-lactating goats fed a high concentrate diet.Eight mid-lactating goats(BW,38 ± 3 kg)were randomly divided into two groups to feed a basal diet(high concentrate diet group,HG group)or the basal diet added with compound buffers(high concentrate diet+ compound buffers group,BG group).Each goat was installed the jugular vein catheters for the blood samples collection in the last4 days of the end of the test.The samples of rumen fluid and blood were collected and analyzed in the final 3 days.The results showed that the compound buffers significantly increased(P<0.05)the average pH value of rumen fluid,and significantly increased(P<0.05 or P<0.01)the rumen fluid pH value at 1,2,4,10 hour after feeding compared with the high concentrate diet.The compound buffers significantly increased the concentrations of acetate,butyrate and TVFA and the ratios of acetic to propionate(A/P)of rumen fluid,portal and hepatic vein plasma(P<0.05 or P<0.01),and A/P ratios in the jugular vein plasma compared with HG group.The hepatic-portal concentrations differences of acetate,butyrate and TVFA were lower(0.05<P<0.1)in adding compound buffers group than HG.Experiment 2:This research was to evaluate the effects of the compound buffers on the metabolism of LCFAs of rumen fluid and the liver in mid-lactating goats fed a high concentrate diet.Experimental animals,grouping,experiment design and sample collection were the same as experimental 1.The samples of rumen fluid and blood were collected and analyzed.The results showed that the compound buffers significantly increased the concentrations of undecanoic acid,lauric acid,linoleic acid,eicosenoic acid and eicosadienoic acid of rumen fluid(P<0.05),and the concentrations of octanoic acid,trans-linoleic acid,PUFA and UFA were trendedrising(0.05<P<0.1)in remen fluid.Compared with HG group,the compound buffers had a tendency to increase the concentrations of arachidonic acid and tetracosenic acid but a trendency to decrease the concentrations of decanoic acid in portal vein plasma(0.05<P<0.1).The compound buffers significantly increased(P<0.05)the concentrations of oleic acid,arachidonic acid and docosahexaenoic acid(DHA),and had a tendency to increase(0.05<P<0.1)the concentrations of palmitoleic acid in hepatic vein plasma.Moreover,the compound buffers markedly increased(P<0.05)the concentrations of lauric acidand trend to enhance(0.05<P<0.1)the concentrations of arachidonic acid in the jugular vein plasma.Experiment 3:This study was to discuss the effects of the compound buffers on milk composition,biochemical parameters and hormone contents of plasma in mid-lactating goats fed a high concentrate diet.Experimental animals,grouping,experiment design and blood sample collection were the same as test 1.The feeding and milking time of goats were at 8 AM and 6 PM a day.Goats were slaughtered and the samples of the liver were taken in the last day of the end experiment.The samples of milk,liver tissues and blood were collected and analyzed.The results showed that the compound buffers significantly increased milk yield,milk fat percentage,milk protein percentage and milk solid not-fat percentage(P<0.05 or P<0.01).The milk yield was significantly higher(P<0.01)in BG group than HG group at 1,2,5,7,10,11,12,13,14 and 15 weeks.The compound buffers significantly decreased(P<0.05)the concentration of NEFA in hepaticvein plasm compared with HG group.In addition,the compound buffers remarkably decreased(P<0.05)insulin and glucagon contents in portal vein plasma.Experiment 4:This research was to consider the effects of the compound buffers on the expression of the genes and proteins of the key fatty acid metabolism enzyme in the goats liver.Experimental animals,grouping,experiment design were the same as the test 1,and the collecting of liver tissues was the same as the test 3.The samples of liver tissues were collected and analyzed.The results showed that the compound buffers significantly increased(P<0.05)the mRNA relative expressions of FAS,AT/MT,LPL,SREBF1 and LXRa of liver tissues,and decreased(P<0.05)HMGCS mRNA relative expression,and also markedly enhanced(P<0.05)the protein relative expression of SREBF1 in liver tissues compared with HG. |
PDF Full Text Request