Stool samples were collected from the cecum of burn-injured and sham mice. Samples were processed and analyzed as previously described (23 (link)). Briefly, weighed cecal specimens were diluted in 25% meta-phosphoric acid at a 1:5 ratio. Samples were then centrifuged at 16,000 × g for 15 min at 4°C, filtered through 0.45-um syringe tip filter (Thermo Fischer Scientific; Waltham, MA), and stored at −80°C until analysis. Butyrate concentrations performed by high-performance liquid chromatography using a 0.01 N sulfuric acid mobile phase (apparent pH 2.0) pumped at a flow rate of 0.7 mL/min through a Rezex ROA-organic acid H+ (8%) 300 × 7.8 mm analytical column (Phenomenex, Torrance, CA) maintained at 65°C. The effluent following a 20-μL injection was monitored with a UV detector set at 210 nm. All equipment was made by Shimadzu (Kyoto, Japan). Peak area of butyric acid was compared to standards ranging for 1 to 100 mM. Butyrate concentrations were corrected for dilution and fecal weight and expressed as μmol per gram of wet weight feces (23 (link), 24 (link)).