Requirement of Non-phytate Phosphorus in Synthetic Broiler Breeder Diet

An experiment was conducted to study the laying performance, shell quality, bone mineralization, hatchability of eggs and performance of progeny (weight at day one and 14 d of age, P content in day old chick, leg score and survivability of chicks) of synthetic broiler breeders fed different levels of non-phytate phosphorus (NPP). Six levels of NPP (1.2, 1.8, 2.4, 3.0, 3.6 and 4.2 g/kg diet) at a constant calcium (Ca) level (30 g/kg) in a maize-soya-deoiled rice bran based diet were tested. Levels of dicalcium phosphate, shell grit and deoiled rice bran were adjusted to achieve the desired levels of NPP and Ca. Each level of NPP was fed with a weighed quantity of feed (160 g/b/d) to 40 female broiler breeders from 25 to 40 weeks of age housed in individual cages. Each bird was considered as a replicate. Egg production, feed/egg mass, body weight, egg weight, shell weight, shell thickness, egg specific gravity, serum Ca content and tibia breaking strength were not influenced (p>0.05) by the variation in dietary NPP levels tested. Increasing the dietary levels of NPP did not influence the hatchability of eggs, phosphorus (P) contents both in egg yolk and day old chick, chick body weight at day one and 14 d of age, leg score and survivability of chicks up to 14 d of age. Maximum response ($p{\leq}0.01$) in shell breaking strength, tibia ash and serum inorganic P contents were observed at NPP levels of 2.09, 2.25 and 3.50 g per kg diet, respectively. The retention of Ca increased, while the P retention decreased ($p{\leq}0.01$) with increasing dietary levels of NPP. Though maximum responses in shell breaking strength, bone ash and serum inorganic P were observed at NPP higher than 1.2 g/kg diet, the broiler breeder performance in terms of egg production, shell quality, hatchability of eggs and progeny performance and their survivability was not influenced by dietary NPP concentrations. It is concluded that synthetic broiler breeders maintained in cages do not require more than 1.2 g NPP/kg diet with a daily intake of 192 mg NPP/b/d during 24 to 40 weeks of age.