An experiment was conducted on one week old broiler chicks to study the effect of supplementation of phytase at Ca: tP ratios of 1:1, 1.2:1, 1.4:1 and 2:1. Sixteen experimental groups of broilers with 8 males and 8 females were constituted at the age of one week. In all eight diets with Ca:tP ratio of 1:1, 1.2:1, 1.4:1 and 2:1 with and without phytase were formulated and randomly allocated to the experimental groups. Significant (P ≤ 0.01) effects of phytase supplementation on the growth performance and feed, protein and caloric conversion ratios were observed during 1–3 weeks of age. However weight gain and feed consumption during 4–5 and 1–5 weeks of age were also affected significantly (P ≤0.01). The effects of widening the Ca:tP ratio irrespective of phytase supplementation on growth performance were significant (P ≤0.01). Similarly significant (P ≤0.01) effects of phytase (600 units/kg) irrespective of Ca:tP ratio on feed consumption (4–5th weeks) and both weight gain and feed consumption (1–5th week) were recorded. The data revealed that supplementation of 600 units of phytase at dietary calcium levels of 0.66–0.80 percent with available phosphorus level of 0.23 percent improved the growth performance of broilers.
Phytase, broiler, growth performance
