Wood-Derived Dietary Fibers Promote Beneficial Human Gut Microbiota

Abstract

The architecture of the gut bacterial ecosystem has a profound effect on the physiology and well-being of the host. Modulation of the gut microbiota and the intestinal microenvironment via administration of prebiotics represents a valuable strategy to promote host health. This work provides insights into the ability of two novel wood-derived preparations, AcGGM and AcAGX, to influence human gut microbiota composition and activity. These compounds were selectively fermented by commensal bacteria such as Bifidobacterium, Bacteroides-Prevotella, F. prausnitzii, and clostridial cluster IX spp. This promoted the microbial synthesis of acetate, propionate, and butyrate, which are beneficial to the microbial ecosystem and host colonic epithelial cells. Thus, our results demonstrate potential prebiotic properties for both AcGGM and AcAGX from lignocellulosic feedstocks. These findings represent pivotal requirements for rationally designing intervention strategies based on the dietary supplementation of AcGGM and AcAGX to improve or restore gut health.

Microbiota-directed fibre activates both targeted and secondary metabolic shifts in the distal gut

“…Preserving the complexity of AcGGM resulted in a highly specific, dose-dependent shift in the composition of the colon microbiome from weaned piglets, with no diverse effect on host growth performance or health status. Our integrated multi-omics analysis, showed that the AcGGM fibre activated a metabolic response in specific Roseburia and Faecalibacterium populations in vivo , as it did in the previous in vitro experiments 4,7 , with both populations expressing proteins from highly sophisticated CE2/CEX-containing mannan PULs that are homologous to a biochemically characterized representative in R. intestinalis L1-82. In conclusion, our data provide a foundation for modulatory strategies to design and match custom dietary fibres to unique enzymatic features of their target organisms, although they bring awareness to the fact that the greater network of interconnected metabolic exchanges and trophic structures inherent to the gut microbiome are highly susceptible to minor dietary interventions.…”

“…This complexity matched the enzymatic capabilities of mannan PULs encoded in human gut Roseburia and Faecalibacterium spp. 4,7 and was predicted to match representatives of the same populations that are indigenous to porcine gut ecosystems 12,13 (Fig. 1f).…”

“…While pure culture 4 , in vitro 7 and germ-free mice studies containing “mini-microbiota” 4 have shown that varieties of AcGGM can be metabolized by butyrate-producers, we wanted to test the accuracy of AcGGM to elicit a specific response in indigenous representatives of our target populations within a highly complex and competitive environment. To assess the potential benefit of our fibre to the host, we chose to introduce AcGGM to weaning piglets immediately after they transitioned from sow’s milk to solid food.…”

“…Within this mannan PUL, a carbohydrate esterase ( Ri CE2) removes 3-O-, and 6-O-acetylations on mannan, whereas a novel Ri CEX removes oriented 2- O -hydroxyl acetylations 6 , which are distinctive features found in limited mannan moieties and inaccessible to most esterases present in the gut microbiome. Closer genome examinations have revealed that putative CE2/CEX-containing mannan PULs are infrequently distributed amongst common fibre-degrading gut microbiota, yet they are prominent within many butyrate-producers including Roseburia spp., Faecalibacterium prausnitzii , Ruminococcus gnavus , Coprococcus eutactus and Butyrivibrio fibrisolvens 4,7 . It is well known that the metabolic attributes of these populations are highly desirable in the gastrointestinal tract, and that their depletion is implicated in colorectal cancer, Crohn’s disease, inflammatory bowel syndrome, ulcerative colitis, forms of dermatitis and several other diseases 8,9 .…”

Isolation and Characterization of Extracellular Vesicles Secreted In Vitro by Porcine Microbiota

“…Several studies have shown a beneficial effect of β-mannan as microbiota-directed fiber (MDF) in a variety of gut microbiomes [32][33][34]. Therefore, it is interesting to study the specific bacterial taxa involved in its degradation and to infer possible mechanisms that mediate the interaction between the microbiota and its host.…”