EFFECTS OF DIFFERENT ENZYME PREPARATIONS ON NITROGEN-RETENTION AND METABOLIZABLE ENERGY OF BARLEY-BASED DIETS IN BROILERS

The efficacy of three different enzyme preparations containing both be ta-glucanase and xylanase activities was studied in a metabolic experi ment with young broiler chicks aged 7-14 days fed on barley-based diet s. Starter diets containing 60% barley with calculated ME content of 1 1.7 MJ/kg were used. The criteria of response were N retention and app arent N-corrected metabolizable energy (AMEn). The inclusion of all en zymes resulted in an increase in N retention as compared with the cont rol group. The degree of increase ranged between 9.7 and 12.8%. The es timated content of AMEn of the basal diet (12.7 MJ/kg) was considerabl y higher than the calculated value and significantly increased (P < 0. 05) to 13.1-13.6 MJ/kg (3.1-7.1%) in the enzyme-treated groups. It is concluded that the improvement of the nutritive value of barley for ch icks by enzyme supplementation is a result of an increase in both N an d energy utilization.