Intestinal bypass. Experimental study on the influence of the excluded intestinal segment.

Five groups of operated rats with 10% of the small intestine in continuity were studied. In one group the animals were subjected to 90% resection of the small intestine, and in the other groups a 90% jejuno-ileal bypass was performed. In two of the latter groups different lengths of the excluded intestinal segment was resected. The bypassed segment was anastomosed to the colon in three of the groups and to the skin as an ileostomy in one group. There were no differences in haemoglobin concentration, liver function parameters or fat absorption between the five groups, but measurements of body weight seem to indicate that the bypassed intestinal segment exerts a general harmful effect on the rats. This effect is more pronounced when the excluded segment is long, and the effect seems to be the same whether it is connected to the colon or to the skin. The mechanism for this effect is not fully ascertained.