Dietary fiber, which stimulates intestinal mucosal growth, is fermented by anaerobic bacteria in the rat hindgut to the short-chain fatty acids (SCFA) acetate, propionate, and butyrate. Butyrate is the preferred oxidative fuel of the colonocyte in vitro, and the provision of preferred intestinal fuels has been shown to stimulate mucosal proliferation in vivo. This study determined whether chronic colonic infusion of butyrate or a combination of SCFA would stimulate intestinal mucosal growth in an animal deprived of its normal source of SCFA, fiber fermentation in the cecum. Adult male Sprague-Dawley rats were fed a fat- and fiber-free elemental liquid diet and underwent cecectomy, ileocolic anastomosis, and insertion of a proximal colonic infusion catheter. Rats were then assigned to receive either a continuous infusion of butyrate (20 mM, 40 mM, or 150 mM), SCFA (70 mM acetate + 35 mM propionate + 20 mM butyrate), or saline, or to receive no infusion. A seventh group underwent proximal colonic transection and reanastomosis. After 7 days, jejunal, ileal, and proximal colonic segments were analyzed for mucosal weight, protein, RNA, and DNA. In the colon, the 40-mM butyrate infusion resulted in significant elevations in all mucosal parameters relative to all three control groups, saline infusion, no infusion, and transection. Both the 20-mM butyrate and the SCFA groups showed increased colonic mucosal DNA compared to controls. In the jejunum and ileum, mucosal DNA content was significantly greater in the SCFA group than in the control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

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To determine whether short-chain triglycerides (SCTs, 1:1 triacetin:tributyrin, wt:wt) enhance intestinal adaptation in short-bowel syndrome (SBS), male Sprague-Dawley rats underwent 60% distal small-bowel resection with cecectomy and received either a chemically defined diet (CD) or a CD containing 40% of nonprotein energy as either medium-chain triglycerides (MCTs) or SCTs. After 12 d the SCT group had significantly increased jejunal mucosal weight compared with the MCT and CD groups and had significantly increased segment weight and mucosal protein compared with the CD group. In the colon the SCT group had significantly increased segment and mucosal weights and mucosal protein and DNA compared with both the MCT and CD groups. Body-weight change and measurements of serum ketones, albumin, glucose, and triglycerides revealed no significant differences among groups. SCTs improved jejunal and colonic adaptive growth and maintained comparable nutritional status in SBS when compared with CD alone or CD with MCTs.