EFFECT OF WHITE-ROT BASIDIOMYCETES-TREATED WHEAT-STRAW ON RUMEN FERMENTATION IN ARTIFICIAL RUMEN

This study evaluated three white-rot basidiomycetes for their potentia l to improve the ruminal degradation of wheat straw. Pleurotus ostreat us (PO), Pleurotus ostreatus-mutant (PO-M) and Trametes gibbosa (TG) w ere incubated on wheat straw for 30 days at 28 degrees C. Neutral dete rgent fiber (NDF), acid detergent fiber (ADF), crude protein and in vi tro dry matter digestibility (IVDMD) were determined. The results demo nstrated increasing crude protein and ash contents (%) in the fungi-tr eated straws. The IVDMD values were also increased. Compared to untrea ted wheat straw (UWS), the NDF and ADF contents were reduced in fungi- treated straw (TWS). Out of the three fractions - hemicellulose, cellu lose and lignin-hemicellulose showed the largest proportionate loss an d lignin the smallest in all three fungi-treated straws. TWS with Pleu rotus ostreatus (TWS-PO), Pleurotus ostreatus-mutant (TWS-PO-M) and Tr ametes gibbosa (TWS-TG) together with barley (80:20%) were used as the experimental diets in the artificial rumen. UWS with barley (80:20%) served as the control diet. The results revealed significantly higher IVDMD values, NDF, ADF and cellulose digestibilities (%) with the expe rimental diets. The production of propionic acid decreased, n-butyric, n-valeric and iso-valeric acids (mmol/day(-1)) increased and the vola tile fatty acid (VFA) production expressed in mol VFAs.kg(-1) digested dry matter decreased in experimental diets. The total microbial produ ction also decreased at fermentation in the experimental diets.