Study On The Optimum Ratio Of Ca And P In Supplemental Phytase Diets Of Growing Pigs

Three experiments was conducted to determine the optimum supplementof phytase to the lower -P corn-soybean-fish meal base diets , the optimum ratio of Ca and P in lower-P and supplemental phytase diets of growing pigs.Experiment 1: One hundred and twenty growing pigs (initial BW= 20-30kg, barrow: gilt =1:1) were assigned to five treatments, 3 replicates in each treatment, 8 pigs for each replicate. Five treatments were as followed:treatment 1 (control group), treatment 2( lower phosphorus group LP), treatment 3(LP+500U/kg phytase), treatment 4(LP+650U/kg phytase) treatment 5 (LP+750 U /kg phytase). The results showed that low the phouphorus in diets could decrease the growth preformencee of growing pigs.while supplying phytase to the lower-P diets could improve the growth profermence significantly (P<0.05).especially when phytase was suppled with 650U /kg,ADG, AFI were increased by 9.8% and 12.2% respectively than treatment1 (control group),but in F/G, CPG all the LP+phytase groups were lower than the control groupExperiment 2: Ninty growing pigs (initial BW = 20 -30kg, barrow: gilt =1:1)) were assigned to five treatments, 3 replicates in each treatment,, 6 pigs for each replicate. Five treatments were as followed: treatment 1 (control group Ca: P=0.97:0.6), treatment 2(LP+650 U /kg Ca:P=0.97:0.50), treatment 3(LP+650U /kg phytase Ca: P=0.89:0.50), treatment 4(LP+650 U /kg phytase Ca: P=0.70:0.50), treatment 5 (LP+650 U /kg phytase Ca:P=0.50:0.50),plasma was taken from each group.The results showed that LP+650U /kg phytase not always improve the growth preformence of growing pigs,but it was improved as the ratio of Ca and P declined .when then ratio of Ca and P was 0.50:.50 the ADG, AFI were increased significantly (P<0.05),however all the LP+650 U /kg phytase groups had a lower F/G> CPG than the control group.The change of biochemical parameters of plasma showed that as the declination of the ratios of Ca and P, serum Ca,P,BUN,AKP were improved but when the ratio was 0.5:0.50 ,serum Ca declilned significantly while serum BUN,AKP increasedExperiment 3: Fifteen pigs (average BW 50kg) were selected from experiment2 ,one pig from each group's each replicate , the diets were as experiment 2. The results showed that the declination of the ratio of Ca and P could improved the digestibility of protein,Ca, P ,energy ,DM,EE. While the concentration of nutrient in manure declined reponsely,which reflected the change of nutrient digestibility...