Potential Enhancing Effects of a Carbohydrase Mixture on Phytase Efficacy in Late-Phase Laying Hens Fed Wheat-Based Diets

Abstract

A total of 360 65-week-old Lohmann LSL-Lite laying hens were used in a six-week experiment to examine the potential enhancing effects of a commercial carbohydrase preparation on phytase efficacy. Two cultivars of wheat (Marvdasht and Sardari) were used to formulate basal diets containing 2.2 g or 2.9 g nonphytate phosphorus (NPP)/kg levels. A further eight dietary treatments were formulated by supplementing these diets with a commercial source of phytase individually or together with a carbohydrase preparation, resulting in 12 dietary treatments in a 2 × 2 × 3 factorial arrangement. The production performance and egg quality traits were not affected by treatments. Birds receiving a diet with Marvdasht cultivar and 2.2 g NPP/kg exhibited the highest serum concentration of thyroxine. The lymphocyte and eosinophil counts increased and the heterophil counts and the ratio of heterophils to lymphocytes decreased in birds receiving phytase supplementation compared with those receiving phytase and carbohydrase simultaneously. According to the results, the supplementation of wheat-based diets with enzymes in the late phase of egg production does not affect productive performance of laying hens. However, enzymes may have special effects on bird health.