Abstract
Two experiments were conducted to investigate the effect of incubation with edible mushroom, Pleurotus ostreatus, on in vitro degradability by cellulase (Ce-DMD) of rice straw. After adjusting the moisture content to about 65%, 286g of chopped straw (100g DM) was packed in a bottle. The straw packs were sterilized, and inoculated with P. ostreatus. In experiment 1, straw substrate and straw substrate mixed with rice bran at 10% were compared. In experiment 2, inoculations with 7 different strains of P. ostreatus were compared. In both experiments, the incubation period was up to 120 days.
In experiment 1, the hemicellulose content of both substrates decreased during incubation, while changes in the cellulose content were small. ADL content increased during the early stage of incubation, and then decreased consistently after 30 days of incubation. The Ce-DMD of straw substrate increased from 31% to 52% after 120 days of incubation, while the Ce-DMD of straw substrate with rice bran was lower than that of the straw substrate. In experiment 2, changes in cellulose, hemicellulose and ADL contents, and Ce-DMD had similar patterns with these in experiment 1. However, the rates and extent of these changes varied very much depending on the strains. Incubation with 4 strains degraded ADL 48-68%, and increased Ce-DMD by 16-22% units.
