Effect of Enzymes of Microbial Origin on in vitro Digestibilities of Dry Matter and Crude Protein in Maize

Abstract

The effects of supplementation of cellulase, xylanase, pectinase, hemicellulase, glucanase, phytase and protease of microbial origins on digestibilities of crude protein (CP) and dry matter (DM) of maize in vitro were examined in the present study. Changes in the viscosity during in vitro digestion were also examined as an index of carbohydrate digestibility. Cellulase significantly improved CP digestibility. Protease, phytase, pectinase, xylanase, glucanase, and hemicellulase had no effect on the CP digestibility. Crude protein digestibility was the highest when all the enzymes except protease were added. No enzymes used had significant effect on DM digestibility of maize. Supplementing maize with protease, cellulase, pectinase, xylansase, phytase, glucanase, or hemicellulase had no effect on the viscosity at both peptic and pancreatic phases. On the other hands, viscosity of maize was the highest when all the enzymes were added simultaneously. These results suggest that the viscosity is not always a good index of carbohydrate digestibility. In conclusion, the present results strongly suggest that cellulase and the combination of carbohydrases improves CP digestibility of maize while protease inhibits the actions of these enzymes.