Comparison of bypass and resection of the small intestine in germfree rats

Germfree rats were subjected to: (1) 90% jejunoileal resection (15 rats) or (2) 90% end-to-side jejunoileal bypass (20 rats). The mortality rate was 67 and 75%, respectively, which is markedly higher than after the same types of operation in conventional rats. Late mortality occurred only in the bypass group. Possible reasons for the high mortality rate are discussed. 5 rats in each group survived and were followed up for 6-12 weeks. At autopsy, the liver was normal, and except for lower serum concentration of albumin in the operated rats, the other liver function tests were normal. There did not seem to be any difference in body weight between the two groups of surviving rats which may indicate that the intestinal microflora is an important factor in causing the difference in body weight after resection and bypass of the small intestine in conventional rats. The number of surviving rats was small, however, and further studies are therefore necessary to give a definite answer to this question.