Determination of non-phytate phosphorus requirement for slow-growing feather-frizzled broilers from 1 to 21 days of age

Abstract

The influence of dietary non-phytate phosphorous (NPP) on growth performance, carcass characteristics, bone quality and serum parameters were investigated to determine the NPP requirement of slow-growing feather-frizzled broilers aged from 1 to 21 days. A total of 480 1-day-old indigenous slow-growing male feather-frizzled broilers were assigned to 1 of 6 treatments with 8 cage replicates of 10 birds each using a completely randomized design. They were fed with corn-soybean meal-based basal diet (containing 0.13 % of NPP) supplemented with 0.00 %, 0.08 %, 0.16 %, 0.24 %, 0.32 %, and 0.40 % of inorganic phosphorus (CaHPO4.2 H2O), respectively. The experimental diets contained a constant 0.90% calcium. Results showed that body weight gain, feed intake, eviscerated carcass ratio, tibia breaking strength, tibia and toe ash or phosphorous concentrations, femoral strength and serum inorganic phosphorous concentration were affected (P < 0.010) by dietary NPP level, and showed significant quadratic responses (P < 0.030) to dietary NPP levels. The estimates of dietary NPP requirements were 0.25–0.36 % based on the best fitted broken-line or quadratic models (P < 0.029) of the above performance, serum and bone parameters. In conclusion, the NPP requirements would be about 0.25 % to obtain the optimum growth performance and carcass yield, and 0.36 % to meet bone development and P metabolism for such slow-growing feather-frizzled broilers fed a conventional corn-soybean meal diet from 1 to 21 days of age.