Amino Acid and Intestinal Protein Metabolism : Working Study

Inclusion Criteria: * volunteers with seronegativity for HIV1 and HIV2 and HCV and HVB * good nutritional state with physical indication mass included between 18,5 and 25kg/m2 * non-smoking volunteers * volunteers without digestive, allergic or haemorrhagic history * volunteers without progressive disease * digestive endoscopy tolerance * age \>=18 and \<= 50years * consent obtained from volunteers Exclusion Criteria: * smoking volunteers * volunteers with digestive, or allergic history * volunteers with haemorrhagic sign * pregnancy * progressive digestive disease * significant progressive disease * volunteers with therapeutic treatment (aspirin) * digestive endoscopy intolerance * volunteers with neurological disorder or with delicate psychological state