Omega wax fused silica capillary column

All samples were dried in an oven (HB-503-LF, Hanbaek Scientific Technology, Bucheon, Korea) at 60°C for 48 h and they were ground and passed through a 1 mm screen with a micro hammer mill (Nr9737840, Culatti AG, Steinenberg, Switzerland). The DM, organic matter (OM), crude protein (CP), and ether extract (EE) were analyzed according to AOAC method [11 ]. The neutral detergent fiber (NDF) and acid detergent fiber (ADF) were analyzed with ANKOM Fiber Analyzer (A200, Ankom Inc., USA) according to method of Van Soest et al [12 (link)]. The non-fiber carbohydrate content was calculated by subtraction of CP, NDF, EE, and ash from 100. Acid detergent insoluble nitrogen (ADIN) was measured for nitrogen using ADF residues, and the nitrogen contents were determined using a distillation unit (B-324, Buchi, Flawil, Switzerland) according to method of Licitra et al [13 (link)]. The pH was obtained using pH meter (Orion Dualster-F, Thermo Fisher Scientific, Waltham, MA, USA), and ammonia nitrogen was determined according to method of Chaney and Marbach [14 (link)]. The VFA was identified by using gas chromatography (HP 6890, Agilent Technologies, Santa Clara, CA, USA), using an Omega Wax Fused Silica Capillary column (Length, 30 m 0.3×2 mm D_f, 0.25 μm, Sigma-Aldrich Co, St. Louis, MO, USA). Carrier gas and detector used was He gas and flame ionization detector, respectively.