Prebiotic potential of novel carbohydrates in an in vitro co-inoculation fermentation model of the bacteria isolated from pig intestine and Salmonella

Innovative plant biomass fractionation methods produce new feed additives that could modulate pig intestinal microbial communities. Such novel indigestible carbohydrates (CHO) were investigated for their prebiotic potential and their influence on Salmonella Typhimurium in a co-inoculation in vitro fermentation model of pig intestines. Inulin, cellobiose, pectic oligosaccharides (POS), isomalto-oligosaccharides (IMO), xylooligosaccharides (XOS), and gluconic acid (GLU) were fermented for 72 h by a bacterial fecal inoculum from pigs in an in vitro model in the presence of Salmonella. Gluconic acid was the fastest fermenting CHO followed by inulin and IMO (P = 0.01). After 6 h, cellobiose yielded the highest lactate molar ratio (0.484). Pectic oligosaccharides fermented more slowly. Xylooligosaccharides and GLU were little fermented (150 and 175 mg short-chain fatty acids/g after 24 h). Nonetheless, GLU yielded the highest butyrate molar ratio of all CHO (0.290 at 12 h; P < 0.01). Although Salmonella counts did not differ, inulin and IMO displayed prebiotical properties, because they supported the highest Lactobacillus and Bifidobacterium populations after 12 and 24 h of fermentation (7.38 to 8.86 log cfu/mL; P < 0.01). Cellobiose and GLU scored well for Lactobacillus too but poorly supported Bifidobacterium (6.41 to 6.92 log cfu/mL; P < 0.01). It is concluded that IMO seems the most promising prebiotic, but owing to their specific fermentation patterns, cellobiose and GLU deserve further consideration.