Interaction of Calcium and Phytate in Broiler Diets. 2. Effects on Total and Soluble Phosphorus Excretion1

ABSTRACT Dietary Ca has been reported to influence the amount of phytate excreted from broilers and affect the solubility of P in excreta. To address the effects of dietary Ca and phytate on P excretion, 12 dietary treat-ments were fed to broilers from 16 to 21 d of age. Treat-ments consisted of 3 levels of phytate P (0.10, 0.24, and 0.28%) and 4 levels of Ca (0.47, 0.70, 0.93, and 1.16%) in a randomized complete block design. Feed phytate concentrations were varied by formulating diets with 3 different soybean meals (SBM): a low-phytate SBM, a commercial SBM, and a high phytate Prolina SBM having phytate P concentrations of 0.15 to 0.51%. Fresh excreta was collected from cages during 2 separate 24-h periods; collection I commenced after the start of dietary treat-ments (16 to 17 d) and collection II followed a 3-d adapta-tion period (19 to 20 d). Ileal samples were also collected at 21 d. Excreta samples were analyzed for total P, wate