Research Note: Estimation of Apparent Protein Digestibility Using Uric Acid-Corrected Nitrogen Values in Poultry Excreta

Apparent protein digestibility values were calculated using three methods based on nitrogen digestibility, corrected and uncorrected for uric acid and amino acid digestibility. Amino acid digestibility, as determined by the summation of individual amino acid values, excluding methionine and cystine (81.2%), closely approximated protein digestibility values derived from nitrogen corrected for uric acid (81.4%). Uncorrected nitrogen values gave misleading results (38.4%). Apparent protein digestibility values, when corrected for uric acid, appear to provide a simple and reliable method for estimating protein digestibility.