Short-chain fatty acid profile in the colon of newborn piglets using fecal water analysis

Short-chain fatty acid production and assimilation is unlikely to occur at significant levels in the newborn because the colon at birth is sterile, and only gradually acquires an anaerobic flora. This study profiled short-chain fatty acid levels in the colon lumen over the initial 21 days of life. Fecal samples were removed surgically from the cecum, right, and left colon from 36 York piglets, 0-21 days of life. Samples were subjected to in vitro dialysis and centrifugation methods to quantitate fecal water short-chain fatty acids, electrolytes, osmolality, and pH. A three-way analysis of variance examined piglet age, colon site of fecal samples, and method of fecal water analysis, for each variable. No differences were found between techniques of fecal water collection. Newborns showed production of short-chain fatty acids as early as the 1st day of life in limited amounts. Levels were stable between days 5 and 14, and then abruptly accumulated in the lumen. Acetate was predominant early, with propionate and butyrate responsible for late peaks. The production and assimilation of short-chain fatty acids was nearly complete proximal to the left colon. Age and colon site showed significant interactions for each fatty acid (p less than 0.001). The combined osmolar contributions of short-chain fatty acids and electrolytes accounted completely for the luminal osmolality after the 2nd wk of life. Previously there was an "osmolar gap" suggesting that lactose or its breakdown products were present in the lumen and were being removed by pathways other than through short-chain fatty acid production.