Phytase supplementation of diets B improved (P < 0.01) apparent digestibility coefficients of nitrogen at four small intestinal sites with increases ranging from 79.9% (proximal jejunum) to 11.3% (distal ileum) culminating in an increase (P < 0.01) in N digestion rates (Knitrogen) of 64% from 2.59 to 4.24 × 10−2 min−1