Effects of phytase supplementation, individually and in combination, with glycanase, on the nutritive value of wheat and barley.

Four experiments were conducted to examine the effects of a microbial phytase (Natuphos), individually and in combination with glycanase preparations with predominantly xylanase (Natugrain Blend) and glucanase (Natugrain) activities, on the nutritive value of wheat and barley. In Experiment 1, the addition of xylanase and phytase increased the AME of a low-AME wheat by 9.7 and 5.3%, respectively. The differences, however, were not significant (P > 0.05). The combination of the two enzymes increased (P < 0.05) the AME of wheat by 19.0% from 2,646 to 3,149 kcal/kg dry matter. A similar trend was seen in terms of ileal amino acid digestibility values of the wheat-casein diet. In Experiment 2, the AME of normal wheat was increased (P < 0.05) by 6.3 and 4.5%, respectively, with the addition of xylanase and phytase. The combination of the two enzymes, however, did not further improve (P > 0.05) the AME values. In Experiment 3, performance of broilers fed a wheat-based diet was not influenced by the addition of individual enzymes, but increasing inclusion levels of the xylanase plus phytase combination linearly improved weight gain (r = 0.58; P < 0.01) and feed efficiency (r = 0.71; P < 0.001). In Experiment 4, the AME of barley was not influenced by the addition of glucanase or phytase. The enzyme combination marginally (P < 0.07) improved the AME at lower concentrations, but had no benefit at the highest concentration.