Characterizing Fecal and Manure Phosphorus from Pigs Fed Phytase Supplemented Diets

We conducted this study to characterize P forms in feces and manure from pigs fed phytase supplemented diets and to determine if higher phytase levels can result in greater reduction in manure P without increased P solubility. Twenty-eight growing pigs were fed diets containing varying levels of supplemental P and phytase. Phosphorus concentrations in feces, urine and manure were determined and fecal and manure P were fractionated. Phytase addition reduced P concentration in feces and manure but increased urine P concentration. The greatest significant reduction in fecal and manure P was in pigs fed diet containing 2000 U phytase kg-1 without supplemental P, with 33% reduction in manure P. Inorganic P constituted more than 85% of fecal and manure P and the percentage decreased with phytase addition. Our study showed that higher phytase levels up to 2000 U phytase kg-1 could offer additional advantage of reducing manure P concentration and solubility.