Assessment of Xylanase and β-Glucanase Impact on Growth Performance and Some Characteristics of Gastrointestinal Tract of Broiler Chicks Fed Wheat and Barley-Based Diet

In this research, the influence of feeding wheat and barley-based diets supplemented with four commercial enzymes containing xylanase and β-glucanase activities were investigated on growth performance and gastrointestinal size and weight of broiler chicks. The diets supplemented with enzyme were compared with unsupplemented wheat and barley- or corn-based diets. A total of 234-day-old male broiler chicks (Ross 308) were allocated to 6 treatment groups, with 3 replicates per treatment group and 13 birds per replicate pen, and all data were analyzed in a randomized complete blocks design. In entire period, adding of all enzymes to the wheat and barley-based diet in similar to corn-based diet were significantly (P<0.05) improved body weight gain and feed conversion ratio of broilers in comparison with wheat and barley-based diet without enzyme. Results showed that enzyme supplementation had no significant (P>0.05) effect on relative weight of pancreas, liver, gizzard, relative weight and length of duodenum, jejunum, ileum, left cecum and colon, but addition of enzymes to the wheat and barley-based diet were significantly (P<0.05) increased relative weight of abdominal fat at 42 day. In general, it seems to that composition of wheat and barley is a beneficial substitution for corn in broilers diet. In addition, there were similar improvements on body weight gain and feed conversion ratio of birds fed diets with enzyme supplementation in entire growth period, therefore choice preference of enzyme supplementation has to base on its economic value.