Effects on primary microbial metabolites. The average increase in (A) acetate (mM), (B) lactate (mM), (C) propionate (mM), (D) butyrate (mM), and (E) branched-chain fatty acid (bCFA; mM) and (F) ammonium (mg/L) levels during the treatment period as compared to the control period upon treatment with old-fashioned oats (OFO) at a dose of 1.4 g/d and pre-cooked oat flour (POF) at a dose of 0.6 g/d, 1.0 g/d, and 1.4 g/d in the proximal (PC) and distal colon (DC) of the human gastrointestinal tract for three human donors tested. For optimal observation of consistent effects over the different donors tested, the average of the three donors is presented (n = 3). Statistically significant differences relative to the control period are indicated with *, whereas statistically significant differences between the different test conditions, in the proximal and distal colon, respectively, are indicated with different letters (p < 0.05).