Interactions between phytase and xylanase enzymes in male broiler chicks fed phosphorus-deficient diets from 1 to 18 days of age

ABSTRACT A total of 735 one-day-old male broiler chicks were used to evaluate the interactions between different levels of phytase and xylanase enzymes on performance and bone mineralization. Basal nonphytate P (nPP)-deficient diets (0.15%) were supplemented with different levels of phytase [0X, 1X, 2X, 3X, and 4X of recommended level (X = 500 phytase units per kg of feed)] alone or in combination with 3 levels of a xylanase preparation [0X, 1X, and 2X of recommended level (X = 0.1 g per kg of feed; a mixture with predominantly xylanase activity)]. A standard curve was developed using different levels of nPP (0.15 to 0.45%) to estimate the P equivalency of each enzyme combination. Treatments were replicated with 7 pens of 5 chicks each. The findings indicated that reducing dietary nPP level had a severely negative influence on bird performance and bone ash content. Results also showed that increasing levels of phytase significantly (P 0.05). In conclusion, phytase was effective in improving bird performance and bone mineralization; however, xylanase supplementation failed to enhance phytase efficacy.