Effect of force-feeding a valine-free diet on gastrointestinal function of rats

To study the effect of an essential amino acid deficiency on gastrointestinal functions, rats were force-fed a 10% amino acid diet devoid of valine for several days, and subsequently a complete amino acid diet. Force-feeding of the valine-free diet for a few days delayed the disappearance of dietary nitrogen from the gastrointestinal tract. ASINGLE FEEDING OF THE COMPLETE AMINO ACID DIET CONTAINING 14C-labeled amino acids or (14C)glucose to rats previously fed the valine-free diet did not improve disappearance of the nitrogen. The absorption of the dietary carbohydrate as well as dietary nitrogen was delayed after feeding the valine-free diet. In spite of the delayed disappearance of dietary 14C-labeled amino acids or (14C)glucose from the gastrointestinal tract, the incorporation of these dietary 14C-labeled amino acids into liver lipids was not different between rats fed the complete amino acid diet and those fed the valine-free diet. Under these experimental conditions, changes in disaccharidase activities in the intestinal mucosa were in parallel with changes in the disappearance of nutrients from the gastrointestinal tract.