ESTIMATION OF THE OPTIMUM LEVEL OF AN ENZYME PREPARATION IN BROILER CHICKS FED ON WHEAT-CONTAINING DIETS

Two experiments on broiler chicks aged 1-21 days were carried out to e stimate the optimum level of an enzyme preparation with predominant xy lanase and beta glucanase activities added to wheat-containing diets. In the metabolic experiment, nitrogen retention and nitrogen-corrected metabolizable energy (AMEn) were measured using diets containing 60% of wheat. The diets used in the growth experiment contained 55% wheat and the criteria of response were growth rate and feed efficiency. In both experiments, the enzyme preparation was included in the diets at five levels ranging from 0 to 0.12 g/kg. Nutrient utilisation and grow th performance increased linearly as the enzyme level increased until the maximum was reached and then remained relatively unchanged. The le vels of enzyme preparation required to obtain optimum nutrient utilisa tion and growth performance as estimated using the bent-stick model we re 0.073 and 0.078 g/kg for N-retention and AMEn and 0.092 and 0.076 g /kg for weight gain and feed efficiency, respectively.