To determine whether incorporation of peptides into diets can improve larval development, sea bass (Dicentrarchus labrax) larvae were fed for 21 d one of three isonitrogenous, isoenergetic semipurified diets in which enzymatic hydrolysate (75% di- and tripeptides) of fish meal proteins was substituted for 0, 20 or 40% of native fish meal proteins. Growth and survival were significantly greater (P < 0.05) in larvae fed peptide diets compared to those fed only native protein, with the best performance exhibited by those fed the 20% level of peptides. Chymotrypsin activity was much higher in groups fed peptide diets compared to that fed all native protein (P < 0.001), indicating a greater proteolytic capacity of the pancreas. At the intestinal level, activities of the brush border enzymes, aminopeptidase, maltase and gamma-glutamyl transpeptidase, increased with age while the cytosolic enzyme, leu-ala peptidase, decreased with age (P < 0.001). These changes in enzymatic activities correspond to the normal development of intestinal digestion. This development occurred earlier in the group fed 20% peptide-substituted diet than in the two other groups. The better larval performances observed in groups fed diets containing peptides can be related to the enhanced proteolytic capacity of the pancreas and the earlier development of intestinal digestion.

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Partial Substitution of Di- and Tripeptides for Native Proteins in Sea Bass Diet Improves Dicentrarchus labrax Larval Development

Renal metabolism of amino acids: its role in interorgan amino acid exchange

Intestinal epithelial cell turnover (proliferation, migration, differentiation, and apoptosis) and gut barrier functions are dynamic processes that are markedly affected by nutritional status, the route of feeding, and the adequacy of specific nutrients in the diet. Emerging studies are defining potential therapeutic roles for specific nutrients and diet-derived compounds (including arginine, glutamate, glutamine, glutathione, glycine, vitamin A, zinc, and specific lipids) in gut mucosal turnover, repair, adaptation after massive bowel resection, and barrier function. The role and regulation of endogenous bowel flora in generating short-chain fatty acids from diet-derived fiber and other diet-derived compounds and the effects of these agents on gut function are increasingly being elucidated. Results of these investigations should define new nutritional methods for trophic and cytoprotective effects on the intestine in conditions such as inflammatory bowel disease, malnutrition, and short bowel syndrome.

Trophic and cytoprotective nutrition for intestinal adaptation, mucosal repair, and barrier function

Glutamine Dipeptides in Clinical Nutrition

Purpose of reviewThe aim of this review is to describe the clinical relevance of supplementation of glutamine from the recent literature. First, new basic research is examined and subsequently recent clinical trials and a metaanalysis are illustrated.Recent findingsGlutamine has a major impact on th

Glutamine: recent developments in research on the clinical significance of glutamine

https://www.gastrojournal.org/article/0016-5085(94)90168-6/pdf

Peter Fuerst

Papers

Effect of free glutamine and alanyl-glutamine dipeptide on mucosal proliferation of the human ileum and colon

Process for the preparation of dipeptides.