The effect of white-rot basidiomycetes on chemical composition and in vitro digestibility of wheat straw.

Five white-rot basidiomycetes were evaluated for their potential to improve ruminal degradation of wheat straw. Polyorus brumalis, Lyophyllum ulmarium III, Trametes gibbosa, Pleurotus ostreatus, and a Pleurotus ostreatus mutant were incubated on wheat straw for 30 d at 28 degrees C. Detergent fiber, crude protein and in vitro dry matter digestibility (IVDMD) were determined. The results showed increasing crude protein and ash contents in fungus-treated straw. IVDMD values were increased in straws treated with P. ostreatus, P. ostreatus mutant and T. gibbosa only. Relative to untreated wheat straw the detergent fiber content-neutral detergent fiber (NDF), and acid detergent fiber (ADF) was reduced in fungus-treated straw and out of three fractions-hemicellulose, cellulose, and lignin, hemicellulose showed the largest proportionate loss whereas lignin the smallest one in all 5 samples of fungus treated straw.