Stoichiometry of in vitro fermentation of pure substrates with particular emphasis on methane production, using the cumulative gas production technique

There is a need to be able to measure the methane producing potential of a range of feedstuffs under different rumen conditions in order to predict more accurately the amount of methane produced per animal. In vitro techniques using rumen fluid as an innoculum can be considered as models of in vivo rumen digestion and have been applied to estimate digestibility of feedstuffs. The in vitro gas production technique (Menke et. al., 1979) can be used successfully to estimate this but there has been limited attempts to use it to estimate the methane producing potential of feedstuffs. The objective was to assess the potential of the technique to do this.Three pure substrates, glucose (G), pectin (P) and cellulose (C) (lg) were pre-wetted in 94ml of medium D (Theodorou et. al., 1994). inoculated with strained rumen fluid (from wether sheep. 10ml) and incubated without agitation for 72h at 39°C.