Conte et al., 2003. Rev. Bras. Zootec., 32 (5): 1147-1156

This study was conducted to determine the effect of phytase and xylanase on the performance and bone mineral deposition of broilers. The treatment diet contained 15% rice bran, low available phosphorus (40%) without iron, zinc, copper and manganese supplement. The control diet was made up of adequate levels of all nutrients without rice bran and without enzymes. Four levels of phytase (Natuphos 5000, 0, 400, 800 and 1200 units/kg) with or without xylanase (Avizyme 13000, 1 kg/ton) were tested. The variables analysed at 21 and 42 days of age were performance and ash, P, Zn, Fe, Mn and Cu levels in the tibia. Liveweight and feed intake increased significantly with supplementation of phytase whereas feed conversion was not affected at 21 and 42 days. The best level of phytase was 1105 and 1023 FTU/kg, where better performance was achieved at 21 and 42 days, respectively. Xylanase did not significantly affect liveweight and feed intake. Xylanase supplement resulted in a significant improvement in feed conversion during the two ages. Phytase supplementation resulted in a linear increase in the contents of ash and phosphorus in the tibia, but did not affect the deposition of Zn, Fe, Mn and Cu in the two studied ages. Xylanase did not have any effect on the parameters evaluated in the tibia.