effect of fungal treatments of fibrous agricultural by-products on chemical composition and in vitro rumen fermentation and methane production

maize stover, rice straw, oil palm fronds and sugarcane bagasse were treated with the white-rot fungi ceriporiopsis subvermispora, lentinula edodes, pleurotus eryngii, or pleurotus ostreatus at 24 °c for 0–6 weeks. the fungi increased total gas production from oil palm fronds by 68–132%, but none of the fungi improved the in vitro rumen fermentability of maize stover. c. subvermispora and l. edodes increased total gas production of sugarcane bagasse by 65–71%, but p. eryngii and p. ostreatus decreased it by 22–50%. there was a linear relationship (p < 0.05) between the proportion of lignin in the original substrate and the increase in in vitro gas production observed for c. subvermispora and l. edodes treatments (r² = 0.92 and 0.96, respectively). it is concluded that c. subvermispora and l. edodes have a particularly high potential to improve the nutritive value of highly lignified ruminant feeds.