Non-starch plant polysaccharides in broiler nutrition – towards a physiologically valid approach to their determination

1996 ◽  
Vol 52 (2) ◽  
pp. 203-221 ◽  
Author(s):  
Coen H.M. Smits ◽  
Geoffrey Annison
Keyword(s):  
Plant Polysaccharides ◽  
Starch Plant

Substrate use prioritization by a coculture of five species of gut bacteria fed mixtures of arabinoxylan, xyloglucan, β-glucan, and pectin

2020 ◽  
Author(s):  
Y Liu ◽  
AL Heath ◽  
B Galland ◽  
N Rehrer ◽  
L Drummond ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Dietary Fiber ◽  
Plant Cell Wall ◽  
Bacterial Species ◽  
Short Chain ◽  
Emergent Properties ◽  
Human Gut ◽  
Fermentation Products ◽  
Plant Polysaccharides ◽  
Human Gut Microbiota

© 2020 American Society for Microbiology. Dietary fiber provides growth substrates for bacterial species that belong to the colonic microbiota of humans. The microbiota degrades and ferments substrates, producing characteristic short-chain fatty acid profiles. Dietary fiber contains plant cell wall-associated polysaccharides (hemicelluloses and pectins) that are chemically diverse in composition and structure. Thus, depending on plant sources, dietary fiber daily presents the microbiota with mixtures of plant polysaccharides of various types and complexity. We studied the extent and preferential order in which mixtures of plant polysaccharides (arabinoxylan, xyloglucan, β-glucan, and pectin) were utilized by a coculture of five bacterial species (Bacteroides ovatus, Bifidobacterium longum subspecies longum, Megasphaera elsdenii, Ruminococcus gnavus, and Veillonella parvula). These species are members of the human gut microbiota and have the biochemical capacity, collectively, to degrade and ferment the polysaccharides and produce short-chain fatty acids (SCFAs). B. ovatus utilized glycans in the order β-glucan, pectin, xyloglucan, and arabinoxylan, whereas B. longum subsp. longum utilization was in the order arabinoxylan, arabinan, pectin, and β-glucan. Propionate, as a proportion of total SCFAs, was augmented when polysaccharide mixtures contained galactan, resulting in greater succinate production by B. ovatus and conversion of succinate to propionate by V. parvula. Overall, we derived a synthetic ecological community that carries out SCFA production by the common pathways used by bacterial species for this purpose. Systems like this might be used to predict changes to the emergent properties of the gut ecosystem when diet is altered, with the aim of beneficially affecting human physiology. This study addresses the question as to how bacterial species, characteristic of the human gut microbiota, collectively utilize mixtures of plant polysaccharides such as are found in dietary fiber. Five bacterial species with the capacity to degrade polymers and/or produce acidic fermentation products detectable in human feces were used in the experiments. The bacteria showed preferential use of certain polysaccharides over others for growth, and this influenced their fermentation output qualitatively. These kinds of studies are essential in developing concepts of how the gut microbial community shares habitat resources, directly and indirectly, when presented with mixtures of polysaccharides that are found in human diets. The concepts are required in planning dietary interventions that might correct imbalances in the functioning of the human microbiota so as to support measures to reduce metabolic conditions such as obesity.

The Influence of Carbohydrate Gelling Agents on Rat Intestinal Transport of Monosaccharides and Neutral Amino Acids in Vitro

1980 ◽  
Vol 59 (5) ◽  
pp. 373-380 ◽  
Author(s):  
B. Elsenhans ◽  
U. Süfke ◽  
R. Blume ◽  
W. F. Caspary
Keyword(s):  
Intestinal Absorption ◽  
Membrane Filtration ◽  
Intestinal Transport ◽  
Michaelis Constant ◽  
Experimental Conditions ◽  
Plant Polysaccharides ◽  
Gelling Agents ◽  
Layer Resistance ◽  
Filtration Technique

1. In the present investigation with rings of everted rat small intestine, carbohydrate gelling agents (plant polysaccharides) such as guaran, pectin, tragacanth, carubin and carrageenan were employed to study their direct effect on intestinal absorption of α-methyl-d-glucoside, d-galactose, l-leucine and l-phenylalanine. 2. Inhibition was found to correlate with the viscosity of the incubation medium, a function only of the polysaccharide concentration, and was independent of other properties of the carbohydrate gelling agents. 3. Reversal of this inhibition was achieved either by washing the tissue free of polysaccharide or by raising tissue agitation. 4. Uptake kinetics in polysaccharide-containing solutions revealed a marked increase of the apparent Michaelis constant although the maximal transport capacity remained essentially unaltered. 5. Since there was no binding of the substrate by the polysaccharides under experimental conditions as judged by a membrane filtration technique, it is concluded that carbohydrate gelling agents may impair intestinal absorption by means of an increased unstirred layer resistance.

scholarly journals Complete Genome Sequence of the Polysaccharide-Degrading Rumen Bacterium Pseudobutyrivibrio xylanivorans MA3014

2020 ◽  
Author(s):  
Nikola Palevich ◽  
Paul H. Maclean ◽  
William J. Kelly ◽  
Sinead C. Leahy ◽  
Jasna Rakonjac ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Bacterial Species ◽  
Glycoside Hydrolases ◽  
Rumen Bacterium ◽  
Protein Coding ◽  
Plant Polysaccharides ◽  
Plant Matter ◽  
Genes Encoding

AbstractRuminants are essential for maintaining the global population and managing greenhouse gas emissions. In the rumen, bacterial species belonging to the genera rumen Butyrivibrio and Pseudobutyrivibrio constitute the core bacterial rumen microbiome and are important degraders of plant-derived complex polysaccharides. Pseudobutyrivibrio xylanivorans MA3014 was selected for genome sequencing in order to examine its ability to breakdown and utilize plant polysaccharides. The complete genome sequence of MA3014 is 3.58 Mb, consists of three replicons (a chromosome, chromid and plasmid), has an overall G+C content of 39.6% and encodes 3,265 putative protein-coding genes (PCGs). Comparative pan-genomics of all cultivated and currently available P. xylanivorans genomes has revealed highly open genomes and a strong correlation of orthologous genes within this species of rumen bacteria. MA3014 is metabolically versatile and capable of utilizing a range of simple mono-or oligosaccharides to complex plant polysaccharides such as pectins, mannans, starch and hemicelluloses for growth, with lactate, butyrate and formate as the principal fermentation end-products. The genes encoding these metabolic pathways have been identified and MA3014 is predicted to encode an extensive repertoire of Carbohydrate-Active enZYmes (CAZymes) with 80 Glycoside Hydrolases (GHs), 28 Carbohydrate Esterases (CEs) and 51 Glycosyl Transferases (GTs), that suggest its role as an initiator of primary solubilization of plant matter in the rumen.

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