Tuesday, December 19, 2017

20/12/2017: Algotherapy in aquaculture production

by MJ van Schoonhoven, Olmix, France

There are many beauties to be found in the world, but one of the true treasures is provided by the seas in the form of algae

Algae can be divided in microalgae and macroalgae, the later more commonly known as seaweeds. Seaweeds are a very diverse group of aquatic plants, which can be divided into three main categories: green, red and brown seaweeds, each of them with their own distinguishing set of polysaccharides.

When looking at the composition of seaweeds, they contain a variable part of carbohydrates (mainly polysaccharides), proteins, minerals, lipids and vitamins. Nutritional studies on marine algae indicate that green, brown and red seaweeds possess good nutritional characteristics and could be used as an alternative source of dietary fibre, protein, vitamins and minerals (Chojnacka et al., 2012; Raposo et al., 2013).

In addition, detailed screening of macroalgae functions revealed new ranges of biological activities including anticoagulant, antiviral and antibacterial, anti-tumoral, anti-proliferative and immuno-modulatory activities. All of them could be of relevance in nutraceutical functional food (Wijesekara et al., 2011a).

Green, brown and red macroalgae cell walls contain large amounts of sulphated polysaccharides, named ulvans, fucoidans and carrageenans respectively, making up from 4-76 percent of seaweed dry weight (Holdt et al., 2011). The high content of these sulphated polysaccharides, their unusual structure, and their biological properties shed a new light on these compounds as promising natural products for medicinal and dietary applications (Rioux et al., 2007; Laurienzo et al., 2010).

The specificity of these algal sulphated polysaccharides stands in the complexity of their structure. Algal sulphated polysaccharides are branched, in contrast with linear polysaccharides like cellulose, which contains only one type of linkage between sugars.

Also, algal sulphated polysaccharides are composed of various, including rare, sugar units (xylose, rhamnose), unlike homo-polysaccharides, like starch, which are exclusively composed of glucose units.

Finally, these sugars can be sulphated, conferring them a special reactivity. The whole of these parameters show a phylogenic similarity with polysaccharides from the animal kingdom such as heparin, known for its numerous biological properties, thus explaining algal sulphated polysaccharide unique activities. Algal sulphated polysaccharides reactivity, hence their biological properties, varies a lot according to the type of sugars and linkages they contain, their level of sulfation and also their molecular weight. Therefore, several sulphated polysaccharide groups, with distinct biological activities, can be found in algae. Their specific extraction is a key to ensure a targeted effect on animals.

Olmix has been studying marine biotechnologies for more than 20 years and has focused in the past 10 years on the extraction and use of specific algal polysaccharides to the service of animal production challenges. One of the polysaccharides isolated from marine macroalgae has been found to have applications supporting animal health.

Read the full article with references, HERE.

Visit the Olmix Group website, HERE.

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