Effects of dietary enzyme on broiler chickens fed diets containing wheat bran

Two hundred and eighty-eight 3-week-old mixed-sex broiler chickens were ran domly divided into three dietary treatment groups and fed diets containing 0, 100 or 200 g/kg of dietary enzyme, respectively, for four weeks. Feed an d water were supplied ad libitum. The parameters studied included growth ra te, feed consumption, feed conversion ratio, carcass evaluation, and the ec onomics of production. The addition of dietary enzyme significantly reduced feed consumption (P<0. 05); on the other hand, feed conversion efficiency and growth rate improved significantly with increasing levels of enzyme incorporation (P<0.05). The reduction in feed intake compared with birds on the control diet ranged fr om approximately 10 to 15%. At seven weeks of age, birds on the 100 g/kg an d 200 g/kg enzyme were respectively 1.9 and 5.8% heavier than their counter parts on the diet with no added enzyme. Birds fed diets containing the high est level of enzyme were 21.1% more efficient in converting feed to body co nstituents. Carcass dressing percentage increased significantly with added enzyme (P<0.05). Dietary enzyme significantly decreased the total cost of feed per bird and the cost per kg gain. Enzyme added at 200 g/kg diet was the most economical .