Effect of phytase and 25-hydroxycholecalciferol on performance and bone quality in broiler chickens

The effect of the addition of 25-hydroxycholecalciferol and phytase to a diet with a standard or decreased content of Ca and P on performance and quality of humerus and tibia bones was studied. The experiment was carried out on 1200 Cobb broilers, kept in floor pens, from 1 to 42-days-of-age. Chickens were distributed into 4 groups, with 3 replicates, 50 males and 50 females each. Diets with standard (groups I, control, and II) or decreased by a 40% level of fodder phosphate (groups III and IV) were used. Experimental diets were supplemented with the following additives: group II - 25-OH-D-3 in the amount replacing 50% of vitamin D-3, group III - phytase (750 PU center dot kg(-1) of diet), group IV - phytase (750 PU center dot kg(-1) of diet) + 25-OH-D-3 in the amount replacing 50% of vitamin D-3. From 1 to 21-days-of-age, as compared to control group, in the groups II and III an improvement of feed conversion was noticed (P=0.05). In the whole rearing period (1-42 days), no decrease in performance, results of slaughter analysis and humerus and tibia bones quality was observed after administering a diet with a reduced level of fodder phosphate and supplemented with phytase or both phytase and 25-OH-D-3.