Three growth trials were conducted to test to efficacy of added microbial phytase in the diets of broilers on growth and feed efficiency. In finisher chicks of trial 1, the control group 1 with added P and in group 2 without P supplement but with microbial phytase (Aspergillus niger EC 3.3.1.8) showed similar live body weights of 1.211 and 1,1932 kg, respectively, whereas P deposit in femur seemed to be better In group 2 (4.73 g) as compared to control group 1 (4.50 g) because the femur weights were > 7g in 3 chicks of group 2 whereas it was not above 6 g In any chick of group 1. In starter chicks of trial 2, age group from day 4 onwards, the respective feeds to both the groups had the same treatments as in trial 1, Growth performance was significantly better (P<0.05) in group 2 (499 g) than in control group 1 (420 g). Trial 3 was carried out on chicks from day 3 to day 45 and the dietary treatments were similar as described. Weight gain was higher in group 2 (576 g) than in control group (545 g) in the starter phase, however, overall growth rate was similar in both thp groups with identical pattern of feed efficiencies, indicating that microbial phytase was effective to make available P from phytic acid in the gastrointestinal tract of chicks,
Phytic acid, Phytase, Phosphorus, Broiler ration
