Chicory root and inulin stimulate butyrate-producing bacterial communities in an in vitro model of the piglet's gastro-intestinal tract

Nutritional management is a promising strategy to alleviate intestinal disorders around weaning in pig production. By-products from the agro-industrial sector are major sources of dietary fibres suitable for livestock feeding and could represent potential prebiotic candidates to modulate beneficial microbiota populations and especially butyrate-producing bacteria. In the present study, chicory root and pulp, citrus pulp, rye bran and soybean hulls were tested in an in vitro batch fermentation model for their microbiota-modulating capacities in comparison to inulin, considered as positive prebiotic control. The microbiota composition in the broths after 6, 12 and 24 h of fermentation was analysed using 16S rRNA gene sequencing. After 24 h, the fermentation of chicory root led to a rise in Firmicutes relative abundance, similar to inulin. Enriched Eubacterium spp. and Ruminococcus spp. levels were found for chicory root and inulin at each of the three time-points in comparison to the other ingredients. These two genera were positively correlated to butyrate production after 12 and 24 h. The tested by-products showed increased levels of Bacteroidetes after 6 h compared to inulin. At each time-point, higher relative proportions of Bacteroides spp. were found with the by-products in comparison to inulin. We can therefore suppose that inulin and chicory root supplementations promoted the Firmicutes phylum by stimulating butyrate-producing bacteria in vitro. Chicory root and inulin could therefore be considered as prebiotic ingredients to modulate butyrate production in vivo, with beneficial effects on intestinal health. © 2021