Effect of different levels of non phytate phosphorus and doses of phytase on the performance of the broiler chicks fed all vegetable diets

Three hundred sixty four, one week old broiler chicks, were subjected to dietary treatments to compare the effects of supplementing different doses (500, 600 and 700 units) of phytase at varying dietary non phytate phosphorus (NPP) levels of 0.2, 0.3 and 0.4 per cent with the recommended dietary NPP level of 0.5 per cent. Twenty six groups of fourteen chicks each (seven males and seven females) were constituted. The average body weight of all the groups was kept similar. A control diet with 0.5 per cent NPP and twelve experimental diets with 0.2, 0.3 and 0.4 per cent NPP level at each of 0, 500, 600 and 700 units of phytase were formulated. Each diet was randomly allocated to a duplicate group of chicks. The experimental birds were reared on deep litter system up to five weeks of age. Weight gain, feed consumption, feed conversion ratio and protein efficiency ratio were significantly (P ≤ 0.05) affected by various dietary treatments during 1–3 and 4–5 weeks of age and the entire growth period. Both the levels of NPP and phytase significantly (P ≤ 0.05) affected the meat: bone ratio and weights of liver, heart and gizzard but, the effect on dressing percentage and shank weights was non significant. From the data it was concluded that broiler diets may be supplemented with 700 units of phytase at 0.4 per cent NPP level.