The digestion of bacterial mucopeptide constituents in the sheep: 2. The digestion of muramic acid

Abstract

Summary 1. In experiments with four lambs cannulated in the abomasum and terminal ileum the amounts of muramic acid, diaminopimelic acid and α-amino nitrogen passing through the abomasum, terminal ileum and rectum were compared. While the concentration of muramic acid and diaminopimelic acid was higher in the ileal than in the duodenal dry matter, the ratio of muramic acid to diaminopimelic acid remained fairly constant at about 1·00:0·86 on a molar basis. 2. There was a very significant net absorption of α-amino nitrogen between the abomasum and terminal ileum, but no net absorption of muramic acid between these points. However, less muramic acid passed out of the rectum than passed through the terminal ileum. 3. It was concluded that in the normal sheep bacterial mucopeptide synthesized in the rumen is not digested in the small intestine, but is extensively degraded by bacteria in the caecum and colon.