Three experiments were conducted to determine the effects of pelleting and extrusion of feeds on the utilization of
phytate P by broilers. The first experiment investigated the effects of pelleting the whole corn-soybean meal (SBM) diet, the corn, or SBM separately on
phytate P utilization. The P-deficient basal diet contained 0.5% total P and 0.2%
phytate P.
Steam pelleting the whole diet, the corn, or SBM separately did not decrease the severity of the P deficiency obtained and there were no indications of increased
phytate P utilization. In the second experiment, the whole corn-SBM P-deficient diet was extruded. Extrusion of the diet did not influence
bone ash and P
rickets, both sensitive criteria of P deficiency. Extrusion decreased Ca, P, and
phytate P retention and decreased the ME value of the diet. In the third experiment,
phytate P retention by chickens fed three commercial pelleted diets was compared to chicks fed the corn-SBM P-deficient diet.
Phytate P retention by the chickens fed the commercial diets was much lower than retention by chickens fed the corn-SBM P-deficient diet. These studies gave no indication that pelleting or extrusion of corn-SBM diets would increase
phytate P utilization by broiler chickens.