EFFECTS OF 3 CHEMICAL TREATMENTS ON IN-VITRO FERMENTATION OF RICE STRAW BY MIXED RUMEN MICROBES IN THE PRESENCE OR ABSENCE OF ANAEROBIC RUMEN FUNGI

Rice straw (Rs) was treated by a sodium chlorite/acetic acid mixture ( Set), ammoniation (At) and alkaline hydrogen peroxide (Athp) methods. The objective was to compare their degradation and fermentation produc ts in the presence or suppression of anaerobic fungi. Significant diff erences (P < 0.01) in degradation of straws were observed during all p eriods of incubation with Set having the highest digestibilities durin g the 48-h and 72-h incubations. The degradation of Set straw was high est in both of the incubations with whole rumen fluid (WRF) and WRF pl us cycloheximide. In sacco digestion followed the order of Set > At > Rs > Athp. Suppressing fungal activity with cycloheximide resulted in a decrease in dry matter degradation, with concomitant decrease in tot al volatile fatty-acid concentration. While the suppression of fungal activity with cycloheximide depressed acetate and butyrate production, it favored an increase in propionate production.