Effects Of Protein,Lysine,Methionine And Threonine Concentrations In Diet On Productive Performance And Serum Biochemical Parameters Of Finishing Pigs

This study consists of two experiments.The effects of dietary protein and lysine levels on the productive performance and serum biochemical parameters of finishing pigs were studied in the experiment 1.The optimum supplementation of methionine and threonine in finishing pigs diet was investigated in the experiment 2.In experiment 1,90 healthy,weighting about 62 kg,three-way crossbred(Duroc × Landrace× Yorkshire)finishing pigs were selected,then according to the similar body weight and the same gender were randomly divided into three groups:the experimental group 1(the control group),the experimental group 2 and 3,each group 30 pigs.The control group pigs were fed to the current diet of the pig farm;the experimental group 2 pigs were fed to the group diet 2;the experimental group 3 pigs were fed to the group diet 3.The feeding experimental results were as follows:(1)ADG of the experimental group 2,3 increased respectively by37.09%(P<0.01)and 39.45%(P< 0.01)compared with the control group pigs.FCR of the experimental group 2 and 3increased respectively by 20.21%(P<0.01)and 18.91%(P<0.01)compared with the control group.The feed cost of per kilogram weight gain of the experimental group 2 and 3(7.51 yuan/kg,8.01 yuan/kg)increased respectively by 2.04% and 8.83% compared with the control group(7.36yuan/kg).(2)Glucose in the experimental group 2 and 3 pig serum increased respectively by 14.66%(P < 0.05)and 17.80%(P < 0.05)compared with the control group.TP in the experimental group 2 and 3 pig serum increased respectively by 7.94%(P<0.05)and 9.75%(P<0.05)compared with the control group.TG in the experimental group 2 and 3 pig serum was higher than the control group(P<0.05).TC in the experimental group 2 and 3 pig serum was lower than the control group(P <0.05).GPT activities of the experimental group 2 and 3 pig serum were lower than the control group(P<0.05).GOT and T-SOD activities of the experimental group 3 pig serum were lower than the control group and the experimental group 2(P <0.05).MDA in the experimental group 2 and 3 pig serum decreased respectively by 21.27%(P<0.05)and 22.17%(P<0.05)compared with the control group.In experiment 2,150 healthy,three-way crossbred(Duroc × Landrace × Yorkshire)finishing pigs were selected,then according to the similar body weight and the same gender were randomly divided into five groups:the experimental group 1(the control group),the experimental group 2,3,4 and 5,each group 30 pigs.The control group pigs were fed to the basal diet(the current diet of the pig farm);the experimental group 2 and 3 pigs were fed to the basal diet supplemented0.075% and 0.15% methionine;the experimental group 4 and 5 pigs were fed to the basal diet supplemented 0.1% and 0.2% threonine.The feeding experimental results were as follows:(1)ADG of the experimental group 3 increased by11.76%(P < 0.05)compared with the control group pigs,ADG of the experimental group 2 increased by 7.06%(P<0.05)compared with the control group pigs,ADG of the experimental group 4,5 increased respectively by3.53%(P>0.05)and 4.71%(P>0.05)compared with the control group pigs.The feed cost of per kilogram weight gain of the experimental group 3(8.45 yuan/kg)was the least,the feed cost of per kilogram weight gain of the experimental group 4,2 and 5 were respectively 8.46,8.76 and 8.88 yuan/kg,the feed cost of per kilogram weight gain of the control group(9.09 yuan/kg)was the most.(2)TP in the experimental group 2 and 3 pig serum was higher than the control group(P<0.05).TG in the experimental group 3,4 and 5 pig serum was lower than the experimental group 1 and 2(P<0.01).IgG in the experimental group 2 and 3 pig serum was higher than the control group(P<0.05).GOT activities in the experimental group 3 pig serum were lower than the control group and the experimental group 2(P<0.05).Based to the results of the two experiments,the conclusion was made:(1)the optimum concentration of protein and lysine in finishing pig diet was respectively 15.25% and 0.90%.(2)the optimum supplementation of methionine in finishing pig diet was 0.15%(in total 0.33%).(3)the supplementation of threonine(0.1% or 0.2%)in finishing pig diet could promote the growth of pigs and reduce the feed costs.