High-sensitivity detection of short-chain fatty acids in porcine ileal, cecal, portal and abdominal blood by gas chromatography-mass spectrometry.

Short-chain fatty acids (SCFA), such as acetate, propionate and n-butyrate, are the main end-products of fermentation in the large intestine. SCFA are rapidly absorbed from the large intestinal mucosa to provide energy to the host. In this study, high-sensitivity detection of SCFA was demonstrated in blood using the gas chromatometry with mass spectrometry (GC-MS). Few studies have measured SCFA in porcine blood. Therefore, SCFA concentrations in the ileal (IV), cecal (CV), portal (PV) and abdominal (AV) vein blood, urine (Ur) and saliva (Sa) were measured by GC-MS. All body fluids were collected from four 5-month-old pigs. Cecal (CD) and ileal (ID) digesta, and cecal (CM) and ileal (IM) mucosa were also collected and their corresponding SCFA concentrations were measured using ion-exclusion high-performance liquid chromatography. GC-MS analyses were successful to determine the SCFA concentrations in the porcine body fluids. n-Butyrate concentration was surprisingly high in CV and its proportion remained higher in CV than that in CD and CM. Acetate showed a constantly high proportion in all porcine body fluids. Propionate was detected at a relatively high proportion in CV, IV and PV, but was low in AV.