A new study results have shown open perspectives for the development of aleurone as a complementary prebiotic selectively targeting colon butyrate producers.

Although amplicon sequencing approaches are nowadays applied routinely to study the bacterial composition of the gut microbiota, their application in prebiotic food ingredient research has been lagging behind. This observation has challenged the emerging scientific consensus regarding a community-level response of the gut microbiota to prebiotic interventions.

It will most likely revive efforts to identify complementary food ingredients, selectively stimulating growth or activity of distinct sets of intestinal bacteria with potential beneficial properties. Wheat bran fibers are considered beneficial to human health through their impact on gut microbiota composition and activity.

Here, the research team assessed the prebiotic potential of selected bran fractions by performing a series of fecal slurry anaerobic fermentation experiments using aleurone as well as total, ultrafine, and soluble wheat bran (swb) as carbon sources. By combining amplicon-based community profiling with a fluorescent in situ hybridization (FISH) approach, the team found that incubation conditions favor the growth of Proteobacteria such as Escherichia and Bilophila.

These effects were countered in all but one [total wheat bran (twb)] fermentation experiments. Growth of Bifidobacterium species was stimulated after fermentation using ultrafine, soluble, and twb, in the latter two as part of a general increase in bacterial load. Both ultrafine and swb fermentation resulted in a trade-off between Bifidobacterium and Bilophila, as previously observed in human dietary supplementation studies looking at the effect of inulin-type fructans on the human gut microbiota.

Aleurone selectively stimulated growth of Dorea and butyrate-producing Roseburia. All fermentation experiments induced enhanced gas production; increased butyrate concentrations were only observed following soluble bran incubation. The study results open perspectives for the development of aleurone as a complementary prebiotic selectively targeting colon butyrate producers.

In conclusion, the resesrchers confirmed the bifidogenic effect of wheat bran fractions. The increase in Bifidobacterium spp. following ultrafine and soluble bran incubations was paired with a decrease in Bilophila relative abundances, matching in vivo observations on the prebiotic effect of inulin. In contrast with the more generalized effects observed upon pericarp bran fraction supplementation, aleurone fermentations selectively stimulated growth of butyrate-producing Roseburia, opening perspectives for its future development as a complementary prebiotic.