The Indian Journal of Small Ruminants

An in vitro study was conducted to determine the Enzyme to substrate (E:S) ratio to maximize the fermentation of dried Cenchrus ciliaris grass. Commercially produced fibrolytic enzymes cellulase, xylanase and pectinase and a proteolytic enzyme protease were used in different ratios. In vitro gas production was significantly higher on enzyme fortified inoculum in the initial 12–24 h of fermentation. Gas production data were fitted to kinetic model with lag for rate determination. Lag time was significantly reduced on cellulase and protease while with xylanase and pectinase improvement was not statistically insignificant. Rate constant of gas production increased significantly with fibrolytic enzymes but not on protease. Average and marginal gas production was significantly higher at lower dose of enzyme. In vitro dry matter digestibility (IVDMD) was increased by 15% on either cellulase or xylanase but only 3% improvement was observed on pectinase and protease over enzyme blank. In vitro neutral detergent fiber digestibility (IVNDFD) was more by 18, 15, 12 and 6%, respectively on cellulase, xylanase, pectinase and protease, compared to enzyme blank. It is concluded that enzyme fortification of inoculum reduced lag time, increased rate of fermentation, IVDMD and IVNDF. It was higher at E:S ratio of 1:100 for cellulase, xylanase and protease while it was 1:50 for pectinase.