Effect of β-glucanase on Performance, Carcass Characteristics, Microflora, Plasma Constitutes and Immunity in Local Broiler Hybrid "Golpayegani-Ross"

The Gram negative bacterium Fibrobacter succinogenes lives anaerobically in the bovine rumen and secretes beta-glucanase. Barley is a cheap food input for poultry production but it is low in nutrients due to its beta glucan content. Supplementing exogenous beta-glucanase (EC 3.2.1.4) to broiler diets can decrease the viscosity of the intestinal content by hydrolyzing the beta-glucan and enhancing nutrient digestibility. In the current study, beta-glucanase enzymatic activity was assayed after extraction from bovine rumen fluid, and then its effect on broiler performance, carcass characteristics, duodenum microbial flora, hematological and immunological parameters was compared with a commercial enzyme. A total of 120 local broilers (Golpayegani-Ross hybrid) was allocated to 3 treatments with 4 replicates per treatment and 10 birds per replicate/pen. Over a 49-day experimental period, broilers were fed a basal diet (T1), basal diet with 10 IU of extracted beta-glucanase and 20% barley (T2) and basal diet with 10 IU of commercial beta-glucanase and 20% barley (T3). T2 significantly increased body weight gain and decreased feed intake over the whole experimental period. Treatments had a significant effect on hematological parameters except low density lipoprotein (LDL) concentration (P<0.01). Treatments did not affect antibody titration. The highest non-eviscerated carcass weight (P<0.05) and eviscerated carcass weight (P>0.05) were associated with the T2. The same treatment also caused a significant increase in lactobacilli and Escherichia coli in the gastrointestinal tract. Consequently, enzyme addition had a positive effect on broiler performance without any adverse effects on humoral immunity parameters.