Effects Of Diet With Different Levels Of Phytase On Growth Performance And Nutrient Utilization Of Broilers

The study was carried out to determine the effects of diet with supplemental levels of phytase on production performance, bone mineralization, health condition, and digestion and metabolization of nutrients in Avian broilers. Also the suitable dose of supplementing phytase in the diet was discussed. The result was showed by the following two trials.Trial one Effects of diet with different phytase levels on production performance and health condition in broilers120 0-day-old Avian female chickens were randomly divided into four groups, 3 replicates per group, and Single factor design was used in this trial to make a comparison between effects of four supplemental levels of phytase (400FTU/kg, 500 FTU/kg, 600 FTU/kg, 750 FTU/kg respectively) in the deit on the basis of a corn-soybean-fishmeal diet (including 0.28% available phosphorus and 0.80% calcium),. The results indicated that all the measumants on grouth performance of broilers were not affected (P>0.05) by supplemental levels of phytase during from 0 to d 21 d, from 22 to 42 d, and for whole time of the trial ( from 0 to 42 d). But dose of 400FTU/kg was lower than others on liveweight of 21 d(P=0.352), gain weight (P=0.356) and daily feed intake (P=0.089) for from 0 to 21d, while dose of 500FTU/kg on gain weight for whole time was higher than that of other there groups on gain weight (P=0.361). The mortality of group 750 FTU/kg was the lowest (10%) among four groups, and that of group 500FTU/kg was 16.67%, and that of doses of 400 FTU/kg and 600 FTU/kg was both 20%. The leg disease rate was 0% in group 500FTU/kg, and that of others were 6.67%. Tibia weight (tibia weight and tibia weight relative to live weight) and content of ash in dehydrated and degreased tibia were not affected by supplemental levels of phytase in all the groups (P>0.05). The length of tibia in levels of 500 FTU/kg and 750FTU/kg were longer significantly than that of 400FTU/kg and 600FTU/kg (P<0.01). The length of tibia relative to live weight in the dose of 750 FTU/kg were longer significantly than that of group 400FTU/kg (P<0.01), and that of group 500FTU/kg was longer significantly than group 600 FTU/kg (P<0.05). The tibia shape of group 750 FTU/kg and group 500 FTU/kg were better than other two groups. The difference among four groups on meat production, the organ development, and meat quality were no significant (P>0.05), but the...