short-chain fatty acids (SCFA), namely acetate, propionate, butyrate, valerate, caproate, isobutyrate, isovalerate, and isocaproate, were deter- mined in the cecal contents by gas–liquid chromatogra- phy (Nelson 1020, Perkin-Elmer, St Quentin en Yvelines, France) as previously described [35]...