STABLE-ISOTOPE MODEL FOR ASSESSING PRODUCTION OF SHORT-CHAIN FATTY-ACIDS FROM COLON-DERIVED SUGAR - APPLICATION IN PIGS

Sugar reaching the colon because of intestinal maldigestion or malabso rption may be fermented to acetate and other short-chain fatty acids, resulting in stimulation of colonic water absorption and cell prolifer ation. To explore this phenomenon in more detail, we have developed a stable isotope model for estimating the fraction of colon-derived gluc ose or lactose that is fermented to acetate, propionate and butyrate. In an initial application of the model, [d(3)]-acetate and either [1-C -13]-glucose or [D-1-C-13]-lactose were infused into the cecum or colo n of piglets, and plateau plasma acetate enrichment was monitored in t he carotid artery. In acutely anesthetized piglets, the fractions of g lucose and lactose fermented to acetate were 17.0 and 20.0%, respectiv ely. In a chronically catheterized piglet, fermentation was higher (34 .2%). When conducted in chronically catheterized animals or via a colo stomy or ileostomy in infants, this model may be used to determine how age, previous surgery or antibiotic therapy affects the efficiency of colonic assimilation of carbohydrate.