Effects of Addition of Cell Wall Degrading Enzyme Derived from Acremonium cellulolyticus Y-94 on Fermentation Quality, Dry Matter Recovery and Cell Wall Components of Grass Silage

Abstract

Using first cutting alfalfa (Medicago sativa L., blooming) and timothy (Phleum pratense L., heading), silage was prepared by adding the following percentages of cellulase derived from Acremonium cellulolyticus Y-94 (cellulase): 0, 0.005, 0.01, and 0.02% to alfalfa, and 0, 0.006, 0.012 and 0.024% to timothy. The quality of alfalfa silage was improved due to two factors: the addition of cellulase caused the production of butyric acid to stop, and as the percentage of cellulase increased, the pH and NH_3-N% in the total nitrogen decreased and the content of lactic acid increased. But the addition of cellulase significantly decreased the recovery of dry matter. On the other hand, the quality of timothy silage was also improved due to the absence of butyric acid. The quality of both silages were high with 0.006% and 0.012% additions of cellulase, but low with 0.024%. The addition of cellulase significantly decreased the content of neutral detergent fiber (NDF) and acid detergent fiber (ADF), and as the rate of cellulase addition increased, the content of NDF and ADF decreased further. On the other hand, the water-soluble carbohydrate (WSC) content significantly increased with the addition of cellulase, and as the rate of cellulase addition increased, the content of WSC further increased. The breakdown of the hemicellulose was not affected by cellulase addition. These results show that an addition of cellulase in the range of 0.005%-0.012% is the best for improving the fermentation quality of silage. More addition of cellulase does not produce favorable results.