Influence of Cellulase Concentrations and Incubation Periods on in vitro Digestibility of Fresh Sorghum Leaf by Simple Cellulase Digestion Method

Abstract

Influence of cellulase concentrations and incubation periods on IVDMD of sorghum fresh leaf determined by simple cellulase digestion method was studied. 1% cellulase concentration is considered to be better than the other concentrations (Fig.1 and 5) and 24 to 48 hours would be long enough incubation period (Fig.2, 3 and 4) for evaluating IVDMD of fresh leaf sampled at both fourth and flag leaf stages. Correlation coefficients between IVDMD by simple and two step cellulase digestion methods assured the reliability of IVDMD by the appropriate simple cellulase digestion method (Fig.5). Fig.4 showed that hydrolysis of fresh leaf in cellulase solution was separated into two phases which are noted by ABE et al. for dried and ground grass samples. In conclusion, hydrolytic response of fresh leaf in cellulase solution is similar to that of dried and ground sample, though the hydrolytic percentage and speed of fresh leaf were lower and slower compared to those of dried and ground samples. Digestion of sorghum fresh leaf in 1% cellulase solution for 24 or 48 hours is proposed as an appropriate simple cellulase digestion method.