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

Abstract

Summary &horbar; Rice straw (Rs) was treated by a sodium chlorite/acetic acid mixture (Sct), ammoniation (At) and alkaline hydrogen peroxide (Athp) methods. The objective was to compare their degradation and fermentation products in the presence or suppression of anaerobic fungi. Significant differences (P< 0.01) in degradation of straws were observed during all periods of incubation with Sct having the highest digestibilities during the 48-h and 72-h incubations. The degradation of Sct straw was highest in both of the incubations with whole rumen fluid (WRF) and WRF plus cycloheximide. In sacco digestion followed the order of Sct > At > Rs > Athp. Suppressing fungal activity with cycloheximide resulted in a decrease in dry matter degradation, with concomitant decrease in total volatile fatty-acid concentration. While the suppression of fungal activity with cycloheximide depressed acetate and butyrate production, it favored an increase in propionate production.

Sustainable Rice Straw Management

“…Using aerobic and anaerobic fungi as pretreatment agents resulted in increased biodegradability of rice straw (Ghosh and Bhattacharyya 1999;Cann et al 1994). Methane production from rice straw AD was increased 31-46% when pretreating it with white-rot fungus and brown-rot fungus (Polyporus ostreiformis using a strawto-fungi ratio of 14:1 and then digested in batch reactors at 30 °C after a 3-week incubation period.…”

“…Methane production from rice straw AD was increased 31-46% when pretreating it with white-rot fungus and brown-rot fungus (Polyporus ostreiformis using a strawto-fungi ratio of 14:1 and then digested in batch reactors at 30 °C after a 3-week incubation period. Cann et al (1994) reported that the anaerobic fungi from the rumen consistently increased the digestibility of rice straw when compared with fermenters where the fungi were inhibited. Haruta et al (2002) also presented the enhancements by a microbial community formed by mixing rice straw, chicken feces, pig feces, cattle feces, and sugarcane dregs.…”