Abstract:

 This experiment was conducted to evaluate the effects of phytase and heat-resistant phytase on growth performance, blood biochemical and physiological parameters in AA broiler. 4 800 1-day-old AA broilers were randomly divided into 6 groups, 5 replicates per group, and were fed with two periods experimental diets from 1 to 3 weeks and from 4 to 6 weeks, respectively. Basal diet was fed in control group, the basal diet P levels was reduced in treatment group 1, AA broilrs were fed diets with 500 and 2 000 U·kg^-1 phytase in treatment group 2 and 3, 250 and 500 U·kg^-1 heat-resistant phytase in treatment group 4 and 5. The results showed that reducing P add level of basal diet, ADG was significantly decreased (P<0.05), F/G was increased; adding phytase, ADG was increased, F/G was decreased, and the effects were better than that of control group. On growth performance, the effects of heat-resistant phytase and 2 000 U·kg^-1 ordinary phytase were similar, and better than that of treatment group 2; reducing P add level of basal diet or adding different source phytases, ALP activity significantly increased, based on this, adding phytase, P in serum and ALP activity return to the level of control group, which had no significant influence on ALB, TP, GLB, GOT, GPT and Ca in serum; different treatments had no significant effects on the T4, T3, GH, IGF-Ⅰ, PTH and CT (P>0.05); compared with control group, IGF-Ⅰin treatment group 1 was decreased, and increased in the phytase groups. Under the conditions of this experiment, we found that the ADG of broiler was improved after adding new heatresistant phytase with low P diets, and F/G was decreased. The effects of two phytases on physiological and biochemical parameters in serum had no significant difference.