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Abstract :
[en] Introduction: Innovative plant biomass fractionation methods produce new feed additives that could modulate the pig intestinal microbial population.
Material and methods: Such novel indigestible carbohydrates (CHO) were investigated for their prebiotic potential and their influence on Salmonella thyphimurium in a co-inocu¬lation in vitro fermentation model of the pig intestines. Inulin, cellobiose, pecto- (POS), iso-malto- (IMOS), xylo-oligosaccharides (XOS), and gluconic acid (GLU) were fermented by fecal microbes for 72h. Salmonella (7.3 log CFU/ml) were co-inoculated after 6h . Fer¬mentation kinetics was modeled and after 6, 12, 24 h, broth was analysed for short-chain fatty acid using HPLC and bacterial population using q-PCR.
Results and discussion: Cellobiose was the fastest fermenting CHO followed by inulin and IMOS (P<0.01). After 6h, cellobiose yielded the highest SCFA production (684 mg/g) and lactate molar ratio (0.484). POS fermented slower. XOS and GLU were little fermented (150 and 175 mg SCFA/g after 24h). Nonetheless, GLU yielded the highest butyrate molar ratio (0.290 at 12h) (P<0.01). Although Salmonella counts did not differ, some CHO dis¬played obvious prebiotic properties, namely inulin and IMOS since they supported the highest growth of Lactobacilli and Bifidobacteria populations after 6 and 12h of fermen¬tation (8.18 to 8.56 log CFU/ml) (P<0.01). Cellobiose and GLU scored well for Lactobacilli too, but poorly for Bifidobacteria (6.41 to 6.92 log CFU/ml) (P<0.01). It is concluded that IMOS seem the most promising prebiotic but owing to their fermentation patterns yield¬ing high levels of lactate or butyrate, also cellobiose and GLU deserve further investigation in in vivo models.