Influence of Exogenous Enzymes on In Vitro Gas Production Kinetics and Dry Matter Degradability of a High Concentrate Diet^#

This study was conducted to evaluate the influence of an exogenous enzyme mixture on in vitro gas production (GP), in vitro dry matter degradability (DMD), metabolizable energy (ME) and short chain fatty acid (SCFA) production in growing lambs fed a high concentrate diet. ZADO® (ENZ) is a powdered, commercially available multi-enzyme feed additive produced from Ruminococcus flavefaciens. Four levels of ENZ (i.e., 0, 5, 10 and 20 mg/g DM; or EO, E5, E10 and E20, respectively) were applied directly to the substrate inside the incubation bottles before addition of buffer medium and rumen fluid, and the treatments were assayed in triplicate runs. Addition of ENZ linearly increased (P<0.05) GP at 6 and 96 h of incubation and tended (P=0.08) to linearly increase GP at 12, 48 and 72 h of incubation. Asymptotic GP was increased linearly (P=0.05) as the level of ENZ increased and the lag time decreased linearly (P=0.003). Concurrently, DMD increased linearly (P<0.001) as the level of ENZ increased, but level of ENZ had no effect on SCFA and ME. Finally, level of ENZ had no influence on rate of gas production. Results suggest that this enzyme preparation has potential to improve efficiency of utilization of high concentrate diets fed to growing lambs.