Effect of phytase enzyme on dietary nitrogen-corrected apparent metabolizable energy and the ileal digestibility of nitrogen and amino acids in broiler chicks

The effect of phytase on the performance, AME(n), and the ileal digestibility of N and amino acids was investigated in a 15-d trial using day-old male broilers with diets that were low in Ca (0.9% for control and 0.79% for phytase treatment) and available P (AP; 0.45% for control and 0.35% for phytase treatment). The assayed dietary phytase activity of crumble diet was 1,149 phytase unit (ETU)/kg. Chromic oxide was added to the diets to estimate ileal digestibility of N and amino acid. Excreta were collected from Day 12 to 15 to estimate AME(n). Weight gain, feed intake, and feed:gain of chicks fed phytase using diets with low Ca and AP were comparable with those observed for chicks fed more normal levels of Ca and AP. The diet with supplemental phytase had a higher AME(n) (P less than or equal to 0.01) compared with the control diet. Chicks fed phytase had higher digestibilities for Val, lie, nonessential amino acids (P less than or equal to 0.05), and total amino acids (P less than or equal to 0.01).