Effects of Dietary Thermostable Phytase Supplementation on Growth Performance and Ca and P Metabolism of Broilers

A study was conducted to study the effects of thermostable phytase supplementation on the growth performance and Ca and P metabolism of broilers for 21 d. 1-day-old Arbor Acres chicks with similar initial body weight were randomly divided into 3 treatments consisting 8 pens of 10 chicks per pen. The control group was given maize-soybean meal basal diet, and the other two groups were fed the basal diet including either 500 U ordinary phytase/kg diet or 500 U thermostable phytase/kg diet. The results indicated that broilers given diets supplemented with phytase have enhanced body weight and weight gain when compared with these fed basal diet (P<0.05), however, growth performance of broilers was similar between two phytase-supplemented groups (P>0.05). Dietary phytase supplementation significantly decreased fecal P excretion (P<0.05) and therefore increased P retention (P<0.05), and this effect was more pronounced in the thermostable phytase-supplemented group (P<0.05). However, the tibia ash content and Ca and P content of tibia ash were all unaffected by diet phytase supplementation (P>0.05). The results indicated that dietary phytase supplementation can improve growth performance and metabolic status of P, and these effects appeared to be more pronounced in the thermostable phytase-supplemented group.