Laminarin in the dietary fibre concept

Abstract

Dietary fibres consist of edible plant polysaccharides that are resistant to digestion and absorption in the human small intestine but undergo complete or partial fermentation in the colon. Seaweeds, notably Laminaria spp, are particularly rich in polysaccharides resistant to hydrolysis in the upper gastrointestinal tract and are, in consequence, considered as dietary fibres. Most of the carbohydrates from Laminaria spp are thought to be indigestible by humans. The main storage polysaccharide of these algae is laminarin, a β-polymer of glucose. The aims of this work were, on the one hand, to compare various methods of extraction of laminarin by partial characterisation of the product obtained and, on the other hand, to study the fate of this polysaccharide and its effects in the gastrointestinal tract in order to determine its potential as a dietary fibre in human nutrition. Among four methods tested to extract laminarin, the best appeared to be a hot HCl-based method. Human digestive enzymes did not hydrolyse laminarin, so this polysaccharide can be considered as a dietary fibre. After ingestion by rats, this polysaccharide was not found in faeces of these animals. It did not increase the intestinal transit and stool output in vivo, but it increased the contractile response of the stomach to acetylcholine in vitro.

Performance of weanling piglets offered low-, medium- or high-lactose diets supplemented with a seaweed extract from Laminaria spp.

“…Similar properties have been reported with b-glucans isolated from S. cerevisiae (Kogan et al, 1989). Secondly, seaweeds are rich in polysaccharides resistant to hydrolysis in the upper gastrointestinal tract, and thus considered as dietary fibres (Devillé et al, 2004). On reaching the hindgut they may be fermented by microflora, increasing the production of short-chain fatty acids (Reilly et al, 2008) and ultimately reducing gut pH.…”

Analysis of bacterial community shifts in the gastrointestinal tract of pigs fed diets supplemented with β-glucan from Laminaria digitata, Laminaria hyperborea and Saccharomyces cerevisiae

“…Seaweeds are rich in polysaccharides that are resistant to digestion and adsorption in the small intestine but are completely or partially fermented in the large intestine by the microbiota present (Devillé et al, 2004;Reilly et al, 2008). Seaweed extracts can potentially be used as feed additives (Gardiner et al, 2008) for both performance improvement and pathogenic bacteria reduction (Allen et al, 2001;Gahan et al, 2009).…”

The effects of seaweed extract inclusion on gut morphology, selected intestinal microbiota, nutrient digestibility, volatile fatty acid concentrations and the immune status of the weaned pig

“…Recently, seaweeds and seaweed extracts have been investigated as a potential feed additive in pig diets due to their wide range of biological actions (Grinstead et al, 2000;Gardiner et al, 2008). Seaweeds are rich in -E-mail: john.vodoherty@ucd.ie polysaccharides that are resistant to digestion and absorption in the small intestine but are completely or partially fermented in the large intestine by the microbiota present (Deville et al, 2004). The seaweed extracts are a potential source of soluble dietary fibres such as laminarins and fucoidans (Michel et al, 1996).…”