The red microalga rhodella reticulata as a source of a dietary ω-3 highly unsaturated fatty acid— eicosapentaenoic acid

Microalgae can be cultured under controlled conditions and serve as a source of valuable biochemicals. The red unicellular alga Rhodella reticulata synthesizes the essential ω-3 fatty acid eicosapentaenoic acid (EPA) as a major constituent of its polar and neutral lipids: EPA can reach up to 40% of the fatty acids of the alga and to more than 1.0% of the biomass. The algal cell also contains a high level (about 30–50% of its dry matter) of sulfated polysaccharides, which may act as dietary fiber. The possibility of using the algal biomass as a dietary source of EPA was investigated in terms of nutritional and short-term toxicological studies in rodents (at a dietary level of up to 10% dry algal biomass of their diet). No adverse effects were observed on the growth rate of the animals, and histological and blood tests did not reveal any toxicity. The liver fatty acids of rats fed a diet containing 10% algal biomass demonstrated an increase in the EPA content from 0.1% EPA in the control animals to 0.7% in the experimental group. A decrease of 30% in serum cholesterol and triglyceride levels was found in mice fed a diet rich in the algal biomass (7.5%) compared with those receiving a diet with a low content of algal biomass (1.8%). This finding could be due to the effect of the EPA present in the algae or to the polysaccharides acting as dietary fiber, or to a unique combination of the two components.