| Choline is an important nutrient necessary for ruminant organisms,and it is involved in various metabolic processes in the body.Choline plays an important role in regulating the physiological performance of dairy cows,such as improving the quality of dairy products,promoting lipid synthesis,preventing fatty liver,regulating the negative balance of energy and so on,but at present,the research of choline on the meat performance of ruminant is less and the results are inconsistent.It is of great significance to explore the appropriate amount of choline in Ruminant Diet for its growth performance,feed utilization and metabolic performance.In this study,Rumen Protected Choline(RPC)was used as a nutrient regulatory factor to study the regulatory effect of choline on the growth performance,digestion performance,fat metabolism and antioxidant capacity of Hu Sheep during fattening stage by means of growth test,digestion and metabolism test and in vitro culture test of cow liver cells.The paper is divided into four chapters.Test 1.Effect of RPC on growth performance,feed intake and feed weight ratio of Hu SheepThe experiment was carried out with 40 Hu Sheep male lambs of similar age and weight of about 15 kg(with normal immune program),which were randomly divided into 4 groups(10 in each group,no significant difference in body weight between groups(P>0.05).Namely,group A(control group),group B(0.1%RPC addition group),group C(0.2%RPC addition group)and group D(0.4%RPC addition group).The experimental period was 60 days(20 days as one stage).The results were as follows:During 0-20 days,RPC had no significant effect on the daily intake and feed weight ratio of Hu Sheep(P>0.05).The daily gain of 0.1%RPC group was significantly higher(P<0.05).In the 20-40 day period,adding RPC could increase the daily intake,daily gain and reduce the feed to weight ratio of Hu Sheep,and the effect of 0.1%RPC was significantly different(P<0.05).During 40-60 days,RPC had no significant effect on the feed weight ratio and daily gain of Hu Sheep(P>0.05),but the daily intake of Hu Sheep increased significantly(P<0.05).During the whole period of 0-60 days,RPC increased the daily intake of Hu Sheep,and there was significant difference in 0.1%RPC group(P<0.05);Adding RPC significantly increased the daily gain of Hu Sheep(P<0.05),while adding RPC decreased the feed weight ratio of Hu Sheep(P>0.05);RPC had no significant effect on the body length,body height and tube circumference of Hu Sheep(P>0.05),but significantly increased the chest circumference(P<0.05).RPC is mainly used to stimulate the intake of feed,improve the utilization rate of feed,increase the chest size of mutton Sheep,and improve the growth performance of mutton Sheep as a whole.Test 2.Effect of RPC on digestion and metabolism of Hu SheepAfter the feeding experiment,the digestion and metabolism experiment was carried out immediately.The experiment design and basic diet were the same as experiment 1,which period was 5 days.The excrement(10%hydrochloric acid nitrogen fixation)of each Sheep was collected regularly every day to determine the effect of different RPC levels on the apparent digestibility of the diet of Hu Sheep.The dry matter(DM),organic matter(OM),crude protein(CP),neutral detergent fiber(NDF),acid detergent fiber(ADF),calcium and phosphorus in fecal samples and diets were tested in the laboratory,and the apparent digestibility was measured by exogenous indicator method:The effect of adding RPC on OM apparent digestibility of Hu Sheep was not significant(P>0.05);0.1%and 0.2%RPC groups had no significant effect on DM and CP apparent digestibility,and the 0.4%RPC group had significant improvement on DM and CP apparent digestibility(P<0.05);With the increase of RPC level,the apparent digestibility of NDF and ADF increased slightly,but the difference of NDF was not significant(P>0.05),ADF difference was significant(P<0.05);With the increase of RPC level,the apparent digestibility of Hu Sheep to calcium increased,and the effect of 0.4%RPC was significantly higher than that of the control group and other experimental groups(P<0.05);The apparent digestibility of phosphorus in the experimental group was significantly higher than that in the control group.RPC can improve the utilization rate of diet as a whole by promoting the digestion and absorption of DM,OM,CP,NDF,ADF,calcium and phosphorus,but the utilization effect of nutrients is related to the level of RPC.Test 3 Effect of choline on metabolism and resist oxidation of hepatocytes in dairy cows.In this study,the primary cells of cow liver(derived from the primary cell line of cow liver provided by Professor Shen Xiangzhen of Nanjing Agricultural University)were treated with 5 treatments respectively:Group A:PBS group;Group B:adding 0.128 mM choline chloride;Group C:adding 0.256 mM choline chloride;Group D:adding 1.024 mM choline chloride and group E:adding 4.096 mM choline chloride.After cell culture,RNA was extracted,reversed and quantitatively detected.The results were as follows:The expression of FASN gene in the liver cells of cows treated with 0.128 mm,0.256 mm and 1.024 mm.choline was significantly decreased(P<0.05),but the difference was not significant in the 4.096 mm group;The expression of ACC a in the liver cells of cows treated with different concentrations of choline decreased,while the expression of PPAR y increased,but did not reach a significant level.The expression level of LPL in the liver cells of the cows treated with choline increased significantly(P<0.05),but there was no significant difference between the different concentrations of choline.There was no significant difference in the expression of SOD 1 in the liver cells of the cows after choline treatment;Only when the added choline reached 4.096 mM,the expression of SOD2 in the liver cells of the cows increased significantly(P<0.05);after choline treatment of 0.256 mM,1.024 mM and 4.096 mM,the expression of SOD3 in the liver cells of the cows was significantly higher than that of the control group(P<0.05);Although the expression of GPX1 gene in the liver cells of the cows after choline treatment,but it did not reach a significant level;The expression of GPX in the liver cells of dairy cows increased significantly after treatment with different concentrations of choline;There was no significant difference in the expression of cat in the liver cells after choline treatment.In conclusion,adding choline to the liver cells of dairy cows can inhibit the synthesis of fatty acids,promote the metabolism of fatty acids,and inhibit the expression of inflammatory genes by improving the antioxidant function of cells... |
PDF Full Text Request