Influence of resistant starch on the SCFA production and cell counts of butyrate-producing<i>Eubacterium</i>spp. in the human intestine

290

179

16S rRNA-targeted oligonucleotide probes were designed for butyrate-producing bacteria from human feces. Three new cluster-specific probes detected bacteria related to Roseburia intestinalis, Faecalibacterium prausnitzii, and Eubacterium hallii at mean populations of 2.3, 3.8, and 0.6%, respectively, in samples from 10 individuals. Additional species-level probes accounted for no more than 1%, with a mean of 7.7%, of the total human fecal microbiota identified as butyrate producers in this study. Bacteria related to E. hallii and the genera Roseburia and Faecalibacterium are therefore among the most abundant known butyrate-producing bacteria in human feces.

Section: Caccae Eubacterium Barkeri E Cylindroides Eubacterium Dosupporting

confidence: 91%

mentioning

confidence: 99%

Oligonucleotide Probes That Detect Quantitatively Significant Groups of Butyrate-Producing Bacteria in Human Feces

Hold¹,

Schwiertz

Aminov³

et al. 2003

290

179

“…The two major groups that have been considered to be active starch degraders, bifidobacteria and bacteroides (36,45,55), however, do not produce butyrate. While it is clear that some recently isolated butyrate producers are also amylolytic (3), their ecological role is as yet unclear and a recent study failed to detect increases in Eubacteriumrelated, butyrate-producing populations in response to starch in a rat model (47). It seems likely, however, that the increase in butyrate formation in these studies involves cross-feeding of fermentation products formed by other non-butyrate-producing species.…”

Section: Discussionmentioning

confidence: 97%

Lactate-Utilizing Bacteria, Isolated from Human Feces, That Produce Butyrate as a Major Fermentation Product

Duncan¹,

Louis²,

Flint³

2004

934

793

The microbial community of the human colon contains many bacteria that produce lactic acid, but lactate is normally detected only at low concentrations (<5 mM) in feces from healthy individuals. It is not clear, however, which bacteria are mainly responsible for lactate utilization in the human colon. Here, bacteria able to utilize lactate and produce butyrate were identified among isolates obtained from 10 ؊8 dilutions of fecal samples from five different subjects. Out of nine such strains identified, four were found to be related to Eubacterium hallii and two to Anaerostipes caccae, while the remaining three represent a new species within clostridial cluster XIVa based on their 16S rRNA sequences. Significant ability to utilize lactate was not detected in the butyrate-producing species Roseburia intestinalis, Eubacterium rectale, or Faecalibacterium prausnitzii. Whereas E. hallii and A. caccae strains used both D-and L-lactate, the remaining strains used only the D form. Addition of glucose to batch cultures prevented lactate utilization until the glucose became exhausted. However, when two E. hallii strains and one A. caccae strain were grown in separate cocultures with a starchutilizing Bifidobacterium adolescentis isolate, with starch as the carbohydrate energy source, the L-lactate produced by B. adolescentis became undetectable and butyrate was formed. Such cross-feeding may help to explain the reported butyrogenic effect of certain dietary substrates, including resistant starch. The abundance of E. hallii in particular in the colonic ecosystem suggests that these bacteria play important roles in preventing lactate accumulation.

“…Such cross-feeding can result in metabolic consequences that would not be predicted simply from the substrate preferences of isolated bacteria. For example, both resistant starch and FOS can be butyrogenic in vivo (23,42,43), although the main utilizers of such substrates so far identified have been lactic acid bacteria (31,43). This may be due to compositional changes of bacterial communities within the colon following the reduction in pH that results from rapid carbohydrate fermentation (44) together with the fact that some butyrate producers are able to utilize those substrates (2,37), but it is also possible that lactate (produced by bifidobacteria, for example) can be converted to butyrate by other species (24).…”

mentioning

confidence: 99%

Two Routes of Metabolic Cross-Feeding between Bifidobacterium adolescentis and Butyrate-Producing Anaerobes from the Human Gut

Belenguer¹,

Duncan²,

Calder³

et al. 2006

718

543

Dietary carbohydrates have the potential to influence diverse functional groups of bacteria within the human large intestine. Of 12 Bifidobacterium strains of human gut origin from seven species tested, four grew in pure culture on starch and nine on fructo-oligosaccharides. The potential for metabolic cross-feeding between Bifidobacterium adolescentis and lactate-utilizing, butyrate-producing Firmicute bacteria related to Eubacterium hallii and Anaerostipes caccae was investigated in vitro. E. hallii L2-7 and A. caccae L1-92 failed to grow on starch in pure culture, but in coculture with B. adolescentis L2-32 butyrate was formed, indicating cross-feeding of metabolites to the lactate utilizers. Studies with [13 C]lactate confirmed carbon flow from lactate, via acetyl coenzyme A, to butyrate both in pure cultures of E. hallii and in cocultures with B. adolescentis. Similar results were obtained in cocultures involving B. adolescentis DSM 20083 with fructo-oligosaccharides as the substrate. Butyrate formation was also stimulated, however, in cocultures of B. adolescentis L2-32 grown on starch or fructo-oligosaccharides with Roseburia sp. strain A2-183, which produces butyrate but does not utilize lactate. This is probably a consequence of the release by B. adolescentis of oligosaccharides that are available to Roseburia sp. strain A2-183. We conclude that two distinct mechanisms of metabolic cross-feeding between B. adolescentis and butyrate-forming bacteria may operate in gut ecosystems, one due to consumption of fermentation end products (lactate and acetate) and the other due to cross-feeding of partial breakdown products from complex substrates.Microbial growth and metabolism in the human large intestine depend to a large extent on the supply of dietary carbohydrates that resist digestion in the upper gut. The fermentation of these compounds, which include plant cell wall polysaccharides and some storage polysaccharides and oligosaccharides, has a major influence on health (9, 20, 43). Indeed, specific carbohydrates are now widely used as functional foods and as prebiotics, based on the concept that they stimulate particular gut bacteria that promote gut health (18) and, at the same time, reduce the populations of nonutilizing bacteria through competition. Inulin and fructo-oligosaccharides (FOS), for example, were originally proposed as prebiotics that selectively stimulate bifidobacteria. While there is evidence that this occurs (11,19,26,45), other studies, using molecular techniques, have revealed that a variety of other bacterial groups, including clostridium-related species, also respond to inulin or FOS supplied as prebiotics in either fermentor experiments or animal models (13, 25).Among the possible explanations for this diversity in response to prebiotics is that complex gut microbial communities involve extensive metabolic interactions (10, 46). Metabolic products produced from dietary prebiotics by one bacterial species may then provide substrates to support growth of other populations, and this i...