In vitro gas production and dry matter dissapearance of solid culture with ligninolytic fungi

Sorghum straw, an abundant agricultural by-product in Mexico, used as food for ruminants, has low digestibility, which is why several methods are used to increase its quality. Therefore, the aim of this study was to evaluate the in vitro fermentative characteristics of solid culture of sorghum straw treated or untreated calcium with hyroxide Ca(OH)(2) and fermented for 20 d with the Pleurotus sapidus and Fomes fomentarius EUM1 fungi. The in vitro gas production technique was used, and Vmax was measured, along with S, L, dissapearance of dry matter, VFA and NH3-N. The experimental design was a randomized complete block design and means were compared using contrasts. The treatment with Ca(OH)(2) showed the best production of fractional gas (p <= 0.05) from 0 to 40 h of fermentation and Vmax (382.10 mL g(-1)). The treatment with F. fomentarius EUM1 and Ca(OH)(2) showed the best Vmax (311.51 and 281.20 nit g(-1)) in comparison with P sapidus and Ca(OH)2 (217.75 and 264.75 mL g). Likewise, P sapidus increased the formation of microbial biomass (p <= 0.01) and F. fomentarius EUM1 increased the production of acetic acid 24 h (p <= 0.01). The conclusion was that the treatment with Ca(OH)(2) improved fermentative characteristics of the straw, and the threatrnent with fungi influenced the formation of microbial mass. Also, there was no synergism in the combined treatment.