The aim of this study was to determine the relationship between gas produced through in vitro gas production test and microbial fuel cell (MFC) technique and introduce new assay for evaluation of ruminants feedstuffs. The treatments were 1) control diet (without whole cottonseed, monensin and vitamin E; CD), 2) diet containing 20.00% whole cottonseed (CSD), 3) diet including 20.00% whole cottonseed plus vitamin E (12000 IU per day; CSDE) and 4) diet containing 20.00% whole cottonseed plus monensin (24 ppm kg-1 dry matter/day; CSDM). For MFC trial, the homemade MFC configuration consisted of two plexiglass cylinders (dual-chambered) was used. The results showed that treatment containing vitamin E had higher gas production compared to the other treatments. Gas production in the monensin treatment was lower than the other treatments. The vitamin E treatment had higher voltage, current and power values in comparison with other treatments. The obtained data showed that addition of monensin in comparison with CSD treatment improved the MFC performance. The results indicated that there were high positive correlations between obtained gas production values and achieved MFC performance in experimental treatments. پرونده مقاله