Intestinal bypass. A comparison between two different bypass operations and resection of the small intestine in rats.

General nutrition, intestinal absorption and liver structure and function were compared in rats subjected to: 1) 90 per cent resection of the small intestine, 2) 90 per cent small intestinal bypass with end-to-side jejunoileostomy (ES bypass), and 3) 90 per cent small intestinal bypass with end-to-end jejuno-ileostomy and anastomosis between the excluded segment and the colon (E-E bypass). The E-E bypass group showed the highest mortality rate and the lowest body weight. In this group the haemoglobin concentration, the faecal fat excretion, and the liver function parameters were more abnormal than in resected rats. Rats with E-S bypass showed results in between the other two groups. In none of the animals was fatty infiltration or cirrhosis of the liver observed. It is concluded that intestinal bypass in rats has a more deleterious effect than resection, and this seems to be more pronounced when the excluded segment is anastomosed to the colon. Factors that might be responsible for this effect are discussed.