Concentrated Raw Fibers Enhance the Fiber-Degrading Capacity of a Synthetic Human Gut Microbiome

Abstract

The consumption of prebiotic fibers to modulate the human gut microbiome is a promising strategy to positively impact health. Nevertheless, given the compositional complexity of the microbiome and its inter-individual variances, generalized recommendations on the source or amount of fiber supplements remain vague. This problem is further compounded by availability of tractable in vitro and in vivo models to validate certain fibers. We employed a gnotobiotic mouse model containing a 14-member synthetic human gut microbiome (SM) in vivo, characterized a priori for their ability to metabolize a collection of fibers in vitro. This SM contains 14 different strains belonging to five distinct phyla. Since soluble purified fibers have been a common subject of studies, we specifically investigated the effects of dietary concentrated raw fibers (CRFs)—containing fibers from pea, oat, psyllium, wheat and apple—on the compositional and functional alterations in the SM. We demonstrate that, compared to a fiber-free diet, CRF supplementation increased the abundance of fiber-degraders, namely Eubacterium rectale, Roseburia intestinalis and Bacteroides ovatus and decreased the abundance of the mucin-degrader Akkermansia muciniphila. These results were corroborated by a general increase of bacterial fiber-degrading α-glucosidase enzyme activity. Overall, our results highlight the ability of CRFs to enhance the microbial fiber-degrading capacity.

Influence of infection with Brachyspira hyodysenteriae on clinical expression, growth performance, and digestibility in growing pigs fed diets varying in type and level of fiber

“…fragilis, and Prevotella melaninogenica. These species are positively correlated with fiber degradation in the intestine (Nakajima et al, 2020;Steimle et al, 2021), and especially Prevotella species can ferment fiber polysaccharides with high short chain fatty acids concentration as a result (Myhrstad et al, 2020). Thus, microbes may interact with B. hyodysenteriae, thereby increasing the NSP digestibility in the cecum.…”

Akkermansia muciniphila and Alcohol‐Related Liver Diseases. A Systematic Review

“…Many nutrients can promote the relative abundance of A. muciniphila in various models ( Table 1 ), [ 14,45–81 ] while others have been shown to decrease the relative abundance of A. muciniphila ( Table 2 ). [ 5,82–87 ] The presence of A. muciniphila has often been described as associated with good health, showing a correlation with α‐diversity of the gut microbiota, which represents the species richness or the number of species in the intestinal ecosystem. [ 88,89 ] Many reviews have summarized the influence of various dietary factors or probiotics modulating the relative abundance of A. muciniphila but exhaustive description of these factors falls beyond the scope of the present review.…”

Gut microbiome-based prediction of autoimmune neuroinflammation

“…We used two different FR diets: The FR diet used for gnotobiotic mice provided a crude fiber content of 3,9% (SAFE, Augy, France, version A04, product code U8233G10R), while the FR diet for SPF-housed mice contained a crude fiber content of 4.23% (Special Diets Service; Essex, UK; product code: 801722). The FF diet was used for both, gnotobiotic and SPF-housed mice, and was manufactured by SAFE Augy, France, based on a modified version of the Harlan TD.08810 diet as described previously (51). All diets were sterilized by 25 kGy gamma irradiation.…”