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

Beneficial modulation of the gut microbiome has high-impact implications not only in
humans, but also in livestock that sustain our current societal needs. In this context, we have
tailored an acetylated galactoglucomannan (AcGGM) fibre to match unique enzymatic
capabilities of Roseburia and Faecalibacterium species, both renowned butyrate-producing gut
commensals. Here, we test the accuracy of AcGGM within the complex endogenous gut
microbiome of pigs, wherein we resolve 355 metagenome-assembled genomes together with
quantitative metaproteomes. In AcGGM-fed pigs, both target populations differentially
express AcGGM-specific polysaccharide utilization loci, including novel, mannan-specific
esterases that are critical to its deconstruction. However, AcGGM-inclusion also manifests a
“butterfly effect”, whereby numerous metabolic changes and interdependent cross-feeding
pathways occur in neighboring non-mannanolytic populations that produce short-chain fatty
acids. Our findings show how intricate structural features and acetylation patterns of dietary
fibre can be customized to specific bacterial populations, with potential to create greater
modulatory effects at large.