Effects of exogenous fibrolytic enzymes on in sacco and in vitro degradation of diets and on growth performance of lambs

This study evaluated the effects of doses of exogenous fibrolytic enzymes (enzyme) on in vitro (IVD) and in sacco degradation (ISD) of dry matter (DM) and neutral detergent fibre (NDF) of diets with 70% concentrate (as DM), as well as their effects on growth performance in lambs. A gas production technique was used to determine IVD. Six ruminally cannulated lambs in a replicated 3x3 Latin Square were used to determine ISD. Three diets (treatments) added with enzyme (0, 3 and 6 g enzyme/kg DM) were evaluated for IVD and ISD. For the growth assay, 48 lambs (17.6±2.5 kg of body weight) fed on two diets with 0 or 3 g enzyme/kg DM were used. There were linear increases of gas production rate as enzyme level in the diets increased. At 48 h of fermentation, there were quadratic increases of IVD as enzyme level increased in the diets. A quadratic change was observed in volatile fatty acids and ammonia N as enzyme was increased in the diet. At 12 h, the highest enzyme level (6 g) increased ISD of DM as compared with the control. There was a quadratic effect on the disappearance rate as enzyme level in the diet increased. Exogenous fibrolytic enzymes improved IVD degradation and fermentation characteristics as well as ISD rate of DM, but there were not any effect of these enzymes on ISD of NDF of diets and growth performance of finishing lambs.