Effects Of Adding Phytase To Diets Containing Different Levels Of Phytate On The Growth Performence And Nutrients Utilization In Both Broilers And Ducks

The paper was conducted to study adding different dose phytase to diets containing different levels of phytate on the growth performence and nutrients utilization in both AA broilers and cherry valley ducks, and aimed to provide theory basis for phytase application.Experiment 1 A total of 504 ducks were selected to study the effects of phytase supplementation in duck diets with different levels of phytate on the growth, nutrients availability and serum biochemical indexes. The study was assigned randomly to seven experimental treatments, which included one dietary treatment with high non-phytate phosphorus(NPP, starter 4.0g/kg;grower 3.4g/kg)as a positive control and other six low-NPP(starter 2.4g/kg, grower 1.8g/kg)dietary treatments. The later was assigned to a 2×3 factorial arrangement. Effects of two factors, phytate phosphorus(PP, 0.20 g/kg in starter, 0.35g/kg in grower)and phytase(500, 1000, 1500 FTU/kg)were determined. Each treatment had 6 replicates with 12 ducks per pen. The results indicated that:(1)The ADG, ADFI(P<0.01)as well as the grower feed conversion(F/G)(P<0.05)was highly improved by phytate and phytase. The diets with high-NPP was superior to the lower treatments(P<0.05), and a significant interactions between phytate and phytase level was both observed(P<0.05). ADG and ADFI in low phytate diets were highly improved by increasing phytase addition, Adding 1000 FTU/kg phytase in high-NPP diets was greater than 500FTU/kg groups, but showed no significance differences with 1500FTU/kg groups. Increasing phytase dose could decline F/G in grower period .(2)Increasing phytase dose could highly improve availability of Ca, P, N in starer period, AME in grower period as well as ileal apparent digestibility of nutrients at 40d(P<0.05). Calcium availability in high phytate diets was significantly higher than the lower treatments(P<0.05), the availability of phosphorus in high phytate diets was lower than in low phytate diets, but it got the opposite in grower period. In starter period, nitrogen availability and AME in low phytate diets with 500FTU/kg phytase addition were lower than the positive group, but other groups could reached or exceeded, nitrogen availability had no signigicant difference between treatments in grower period. The availability of phosphorus, nitrogen, IDE in high phytate diets were significant higher than in low phytate diets at 40d(P<0.05), but the availability of calcium was lower(P<0.05), the availability of calcium and nitrogen reached consistent when phytase dose got to 1500FTU/kg, and availability of phosphorus in in low phytate diets with 1000FTU/kg phytase addition, 1500 phytase dose in high phytate diets could reached to the positive group, IDE in each treatment was higher than the positive group.(3)Increasing phytase dose could decline the ALP activity(P<0.05). Serum P content in 21-d was highly improvded by adding phytase, but there was no significant difference in serum Ca content between treatments.Conclusion:The date suggested adding phytase in low-NPP diets can significantly improved growth rate and feed intake, availability of calcium and phosphorus ,nitrogent availability in starter period , AME in grower period as well as the nutrients digestibility at 40d in ducks.The digestibility of calcium and the availability of phosphorus in starter period with high phytate diets was higher than the lower treatments, but dose-effect has differences between each nutrients availability. Increasing phytase ?dose could decline ALP activity, phytate and phytase had no significant influence on serum Ca content.Experiment 2 504 1-d old mail AA broilers and cherry valley ducks was selected to study the influence of phytase, on growth performance and nutrients utilization in stater diets containing different concentrations of phytate.The study was conducted as a 2×3 factorial arrangement of treatments with 2 concentrations of phytate(PP,2.4g/kg;3.4g/kg)and phytase(500, 1000, 1500 FTU/kg), and it also include one positive group with 4.0g/kg NPP in diets, each treatment has 6 replicates, The results indicated that:(1)Adding more than 500FTU/kg dose phytase in diets, the growth performance of broiler with low phytate diets were superior to the higher treatments(P<0.05). ADFI and growth rate were highly improved by adding phytase dose(P<0.05)in duck diets, the diets with high phytate was superior to the lower treatments. The interaction between phytate and phytase on growth was not abserved in both broilers and ducks.(2)Adding phytase in diets, the availability of Ca in both broilers and ducks, N availability in broilers with high phytate diets was significantly superior to the lower treatments, but P availability was the opposite. Adding more than 500FTU/kg dose phytase had no significant influence on broiler growth, but adding 1500FTU/kg dose phytse in duck diets coude achieved the optimum Ca availability, and 1000FTU/kg dose was proper for N availability and AME, the interaction between phytate and phytase could highly effectd AME in ducks.Conclusion:(1)In the experiment condition, the optimum phytase dose was 500FTU/kg with low phytate diets(PP 2.4g/kg)for broilers, and 1500FTU/kg with high phytate diets(PP 3.4g/kg)for ducks while taking growth performance as observation index.(2)Adding phytase to the diets, availability of calcium with high phytate diets was superior to the lower treatments in both broilers and ducks, but phosphorus availability was higher in low phytate diets. Adding more than 500FTU/kg phytase dose had no improvement for the nutrients utilization in broilers, but the opotimun phytase dose in ducks was 1000FTU/kg and 1500FTU/kg when taking availability of calcium, N and phosphorus seperately as the observation index in stater period.