FORMULATING AN APPROPRIATE ENZYME COCKTAIL FOR EFFECTIVE DRY MATTER DIGESTIBILITY OF MAIZE STOVER

Abstract

Across the East African Community, ruminants are fed mainly low-quality roughages due to feed scarcity. Maize stover has the potential to alleviate the feed shortages due to its abundance, however, it is of poor nutritive value owing to the high content of lignocellulosic material and lower degradation rates which negatively affect animal performance. A series of in vitro studies were undertaken to determine the effectiveness of cellulase and xylanase, singly and in combination, on dry matter (DM) digestibility of maize stover. Cellulase and xylanase were added individually to ground maize stover at increasing rates of 0 (control), 0.5, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5 g/kg DM. The best individual doses of 1.5 and 2.5 g/kg DM for cellulase and 3.5, 4.5, 5.5 g/kg DM for xylanase were selected to study the effect of cellulase and xylanase combination on DM digestibility of maize stover. Cellulase at 2.5g/kg DM, xylanase at 0.5 g/kg DM and cellulase-xylanase combination of 1.5 and 0.5 g/kg DM, respectively, were selected to evaluate their effect on DM digestibility of maize stover when combined with pectinase in graded levs of 1.5, 2.5 and 3.5 g/kg DM of maize stover. In vitro DM digestibility (IVDMD) of maize stover increased with the addition of cellulase compared to the control (P<0.05). The addition of xylanase to maize stover increased IVDMD compared to the control. When cellulase and xylanase were combined, they increased (P<0.05) IVDMD of maize stover compared to the control but no significant (P>0.05) differences were observed amongst the enzyme combinations. When combined with graded levels of pectinase, cellulase, xylanase and cellulase-xylanase combination increased (P<0.05) IVDMD of maize stover compared to the control. Based on the results of this study, the addition of fibrolytic enzymes to maize stover increased IVDMD compared to untreated maize stover. Based on the findings, an enzyme cocktail comprised of cellulase, xylanase and pectinase at 1.5, 0.5 and 1.5 g/kg DM, respectively, has the potential to increase the in vitro DM digestibility of maize stover. (Key words: Maize stover, fibrolytic enzymes, ruminants, in vitro)