Faecal microbiota and short-chain fatty acids in patients receiving enteral nutrition with standard or fructo-oligosaccharides and fibre-enriched formulas

Abstract

Prebiotics potentially increase the growth of bifidobacteria, which may minimise the risk of diarrhoea in patients receiving enteral nutrition (EN). The present study aimed to compare the concentrations of faecal microbiota and short-chain fatty acids (SCFA) in patients receiving EN with either a standard formula or one enriched with fructo-oligosaccharides (FOS) and fibre. Forty-one hospitalised adult patients (25 males, 16 females) who were on exclusive EN for at least 12 days were recruited to a cross-sectional study. Faecal samples were collected and analysed for major groups of microbiota using fluorescent in situ hybridisation and SCFA concentrations were analysed using gas liquid chromatography. There were generally low concentrations of the major bacterial groups, including bifidobacteria, in all patients receiving either standard or FOS/fibre-enriched formula [bifidobacteria: 6.6 (1.3) versus 7.0 (2.0) log(10) cells g(-1) dry faecal, P=0.199]. However, faecal butyrate concentrations were higher in patients receiving the FOS/fibre-enriched formula compared to standard formula [20.5 (21.6) versus 4.6 (6.7) μmol g(-1) dry faecal, P=0.006]. Low concentrations of faecal bifidobacteria were identified in these patients, which potentially increases their risk of diarrhoea. Other microbiota groups may utilise FOS/fibre, leading to different butyrate concentrations between the two cohorts.