2.7. Fecal pH, Short-Chain Fatty Acids (SCFAs) and Biomarker Analysis
Fecal pH was measured with an electrode-fitted pH meter LAQUAtwinB-712 (HORIBA, Kyoto, Japan) after suspending fecal samples in Milli-Q water and sterilizing at 85 °C for 15 min for sterilization of fecal samples.Fecal SCFAs (acetate, propionate, n-butyrate, iso-butyrate, n-valerate, iso-valerate, n-caproic acid) in ethyl acetate extract were determined by gas chromatography system GC-FID (7890B, Agilent Technologies, Santa Clara, CA, USA) and a DB-WAXetr column (30 m, 0.25 mm id, 0.25 μm film thickness, 1.2 mL/min) as described previously [Commercially available ELISA kits were used to determine fecal secretory immunoglobulin A (sIgA: Human IgA ELISA Core Kit, LABISKOMA, Seoul, Republic of Korea) and calprotectin (IDK