This experiment was conducted to investigate the effect of fat content (high: 165 g fat kg-1 DM and low: 25 g fat kg-1 DM) of sodium hydroxide (40 g kg-1 DM) or formaldehyde (3 and 6 g kg-1 DM) treated sunflower meal on in vitro gas production parameters used mediums containing isolated rumen microorganisms including total rumen microbiota (TM), bacteria (B), protozoa (P) or fungi (F). Results showed formaldehyde (both applied concentrations) caused a significant reduction in the rate and gas production from fermentable fraction of sunflowermeal samples by the isolated microbial groups. Sunflowermeal with high fat concentration treated withNaOH had the highest gas production (p<0.05) when fermented by the rumen isolated micro-biota (193, 33, 89 and 175 mL 500 mg DM sample for TM, B, P and F, respectively). Gas produced from the chemically treated or untreated high fat containing sunflower meal was more than the low fat content samples. Therefore, it was concluded both fat concentration and chemical treatments used in the present study may affect the fermentation potential of sunflower meal as evaluated by the applied in vitro procedure. In addition, in vitro gas production of high and low fat content sunflower meal by isolated rumen microbiota fractions are influenced by formaldehyde and NaOH treatments

Keywords