Effect of different enzyme supplementation on the performance and ileal pH of broilers fed wheat-and barley-based diets

This experiment was conducted to study the effects of different enzyme supplementation to wheat-and barley-based diets on the live weight gain, feed efficiency, dressing percentage and ileal pH of broiler chickens. Two hundred fourtyfive, day-old Ross-PM3 chicks were randomly assigned to a control and four treatment groups. Starter (1 to 21 days old) and grower (22 to 42 days old) diets were given without (control) or with different enzyme preparations, which are Avizyme 1200 (1000 mg/kg), Kemzyme Dry (500 mg/kg), Roxazyme-G (200 mg/kg) and Wheatzyme (700 mg/kg). At the end of the six week, average live weights of broilers were 1793.03, 1892.55. 1820.21, 1897.96 and 1751.09 g, and feed/gain ratios were 1.95, 1.91, 1.91, 1.85 and 1.94 for control and treated groups, respectively. At slaughter, dressing percentages were 71.78, 71.98, 72.66, 73.26 and 72.89%. There were no significant differences between groups in these respects, except that the average live weights in broilers fed Avizyme 1200 and Roxazyme-G supplemented diets were 5.55% and 5.85% respectively, higher than the control (p<0.01). Ileal lumen contents from ten chicks for the pH determinations were individually diluted 1:10 with deionised water. Mean pH for the control and treated groups were 6.41, 5.89, 6.11, 5.66 and 6.14. There were significant differences between groups in ileal pH, so that ileal pH level of broilers in the Roxazyme-G group was lower than the control, Kemzyme Dry and Wheatzyme groups (p<0.05). The results of this study indicate that, inclusion of some commercial enzymes (Avizyme 1200 and Roxazyme-G) in wheat-and barley-based diets lead to an improvement in broiler chick performance. However, the effect of Kemzyme Dry and Wheatzyme on feed conversion efficiency were more pronounced than on weight gain. In addition, supplementation of enzyme preparations to broiler diets might positively influence on animal health because of decreased ileal pH.