Faecal short-chain fatty acids after colonic surgery.

Carbohydrates from dietary fibre and starch are broken down by the anaerobic microflora to short-chain fatty acids (SCFA) in the caecum and ascending colon. In this study the adaptation of the remaining distal colon or ileum to resection of various lengths of the proximal colon was investigated. Faecal SCFA concentrations (mumol/g wet weight) were measured after right hemicolectomy (n = 10), subtotal colectomy (n = 3) and total colectomy (n = 8) and compared with SCFA in control subjects (n = 21). After right hemicolectomy faecal SCFA (48.7 +/- 5.6) were not different from values obtained in control subjects (47.8 +/- 4.0). SCFA levels after subtotal colectomy (14.5 +/- 0.8) and total colectomy (6.7 +/- 1.4) were significantly lower than after right hemicolectomy and in controls. It is concluded that, after right hemicolectomy, the remaining left colon offers conditions favourable to bacterial fermentation. After subtotal or total colectomy, however, postoperative conditions do not allow a normal fermentative activity. The consequences of a reduced SCFA production for sodium and fluid absorption are discussed.