Resistance of potential carbohydrate prebiotics to gastric acidity, enzymatic hydrolysis and absorption

Non-starch polysaccharides and resistant starch that escape digestion in the small intestine of poultry and pigs may undergo microbial fermentation in the hindgut to produce short-chain fatty acids and gases. This reduces luminal pH and promotes proliferation of beneficial microbial species to the detriment of pathogenic bacteria. The efficiency of carbohydrate fermentation in the hindgut may be limited by the presence of large amounts of protein and the fermentability of protein. Low protein content and fermentability are some of the criteria required for an ingredient to be considered for use as a prebiotic. In this study, 10 ingredients were screened for resistance to gastric acidity, enzymatic hydrolysis of protein and gastric acidity, enzymatic hydrolysis of protein and gastrointestinal absorption using an in vitro pepsin/pancreatin digestion method, followed by a modification of the dialysis bag method (Gauthier et al., 1986; Savoie and Gauthier, 1986).