Exogenous Fibrolytic Enzyme Cocktail for Improvement of Nutrient Utilization from Sorghum Stover in Cattle

Abstract

The study was undertaken to evolve appropriate fibrolytic enzyme cocktail comprising of cellulase, xylanase and β-D glucanase for sorghum stover based on in vitro DM digestibility (IVDMD) using rumen liquor from cattle maintained on sorghum stover. At first, cellulase and xylanase were added individually to ground sorghum stover at an increasing dose rates (100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600, 32000, 38400, and 44800 IU/g) subjected to higher IVDMD. The doses attributed to higher IVDMD (P < 0.01) for cellulase (32000, 38400 and 44800 IU/g) and xylanase (12800 and 25600 IU/g) were selected for formulating cellulase- xylanase combinations and the enzyme combinations (cellulase-xylanase, IU/g) with higher IVDMD (P<0.05) selected were 32000 and 25600, 38400 and 12800, 44800 and 12800 and 44800 and 25600 IU /g. To these combinations β-D glucanase was added at (0, 100, 200, and 400 IU/g) and a synergistic effect of β -D glucanase was observed. To lower doses of cellulase (3200 IU) and xylanase (25600 IU), 400 IU β -D glucanase was required, but for other higher combinations of cellulase-xylanase, 100 IU of β -D glucanase was sufficient. The study indicated that exogenous fibrolytic enzymes have the potential to increase the nutrient digestibility from sorghum stover and based on in vitro studies, the enzyme cocktails (cellulase- xylanase- β-D glucanase, IU/g) 32000 - 25600 - 400 or 38400 - 12800 - 100 was optimum for enhancing nutrient utilization from sorghum stover for large ruminants.