Study On Alfalfa Saponins On Cholesterol Metabolism Of Laying Hens

This paper was conducted to investigate effect of adding different levels alfalfa saponins on growth performance, egg quality, cholesterol content, serum biochemical indexes,antioxidant function and bile acid of laying hens. To measure expression of mRNA which is related to cholesterol metabolism. The results as follows:Exp.1:Alfalfa saponins was applicated in the diet of laying hens.150hailanhe laying hens which was190-days-old were randomly divided into5treatment groups with5replicates and6per replicates. The experiment lasted77days. The control group was fed with the basal diets, The treatment groups were fed with60mg/kg、120mg/kg、240mg/k、480mg/kg alfalfa saponins respectively adding to the basal diets. The results showed that:(1) Feed consumption of treatment groups Ⅰ～Ⅳ were lower than that of control group in different periods; Laying rate of treatment group1and treatment group Ⅱ were higher than that of control group in different periods, Laying rate of the other two groups had no disciplinary change. Feed/egg ratio of treatment groups Ⅰ～Ⅳ were lower than that of control group.(2) Treatment groups Ⅰ～Ⅳ had no disciplinary effect on egg quality of laying hens.(3) Cholesterol content of the yolk could be decreased by alfalfa saponins, Cholesterol content of per100grams of egg could be very significantly decreased by alfalfa saponins on15d、30d and45d (P<0.01). Treatment groups Ⅰ～Ⅳ had no disciplinary effect on cholesterol content which was in liver and muscle, Cholesterol content in liver>thorax muscle>leg muscle.(4) HDL-C could be increased and VLDL-C could be decreased by alfalfa saponins, LH and E2which were existed in serum could be increased by alfalfa saponins.(5) Antioxidant function of liver,thorax muscle and leg muscle of laying hens could be increased by alfalfa saponins.(6) Bile acide of treatment groups Ⅰ～Ⅲ was hihger than that of control group in laying hens’waste. Bile acide of control group was more than that of other groups in liver.Exp.2:Effect of adding different levels alfalfa saponins on mRNA expression of OVR in the ovary and on mRNA expression of HMGR、APO-Ⅱ、CYP7A1in liver. Experimental design of Exp.2is the same with Exp.1.The results showed that:(1) mRNA expression of OVR in the ovary of control group was very significantly lower than that of treatment groups Ⅰ～Ⅳ(P<0.01).(2) mRNA expression of CYP7A1and apoVLDL-Ⅱ in the liver was very significantly increased by alfalfa saponins(P<0.01).(3) mRNA expression of HMGR in the liver of treatment groups Ⅰ～Ⅲ was very significantly higher than that of control group(P<0.01), mRNA expression of HMGR in the liver of treatment groupⅣ was lower than that of control group, which had no significant diffenerces(P>0.05).