An Evaluation of Endo-β-D-mannanase (Hemicell) Effects on Broiler Performance and Energy Use in Diets Varying in β-Mannan Cont

Two experiments were conducted to evaluate the effects of a commercial endo-β-D-mannanase (Hemicell) on overall performance, MEn, net energy for gain, and some serum parameters of broilers fed diets varying in β-mannan level (experiment 1) and to evaluate effects of enzyme level on the same variables in broilers fed diet high in β-mannan (experiment 2). As a semipurified β-mannan source, guar gum was used to alter the dietary β-mannan level. In experiment 1, guar gum was added at 0, 0.5, 1, and 2% in a corn-soy-based starter diet with (0.05%) and without endo-β-D-mannanase supplementation in a 4 × 2 factorial design. Enzyme supplementation improved (P < 0.01) feed efficiency at control and each guar gum inclusion level, whereas 2% guar gum supplementation reduced (P < 0.01) BW and increased (P (