The sector of algae cultivation is poised to be an impressive market in near future
The use of algae, particularly marine algae, as an animal feed has increased eight per cent each year for the past 30 years, according to experts. Algae cultivation is very promising as they do not need fertilizers, freshwater or pesticides and require on average one-sixth of the surface needed by terrestrial plants. In contrast with terrestrial plants that draw nutrients from their roots, algae absorb nutrients from their entire surface greatly increasing productivity. Moreover, their colloidal structure, which allows greater water retention. The Earth has seven production basins of brown seaweed, with Asia being at 75 per cent and Northern Europe coming last with only two per cent of world production. The required conditions for the cultivation of seaweed are cold water with no ice. Nevertheless, the real challenge is to establish a viable seaweed industry and bring the development of seaweed cultivation within regional development. In the animal feed industry, seaweed meals are increasingly used as a dietary supplement, but seaweed extracts still remain quite inaccessible economically. Algae can be used as a functional fibre complementary to other prebiotics, according to evidence from French researchers. In other roles, algae are used in small quantities over a short period of time, often as a supportive measure. This is the case with lithothame and fossil calciferous algae, which has a structure of calcium carbonate and magnesium.
Current research has focused on the immune stimulation action and anti-inflammatory effects of marine sulfated polysaccharides (MSP). Depending on the type of polysaccharide, there is a general positive action on innate immunity, with different mechanisms of cell recognition and many types of pathways (activation of the complement, of the lymphocytes, production of cytokines). There have been reports on positive antiviral effects, regulation of inflammation process, significant anticoagulant properties and anti-tumoral activity.
Algae and animal feed
Several projects in France are working toward developing processes to make algae cultivation economically viable as an animal feed, in the same terms as wheat and corn. The next step after seaweed farming is offshore marine aquaculture with shellfish and seaweed culture on the same site like open ocean aquaculture. Further research is needed to reduce the obstacle represented by the high-fibre concentration and improve protein digestibility to transform seaweed into an animal feed ingredient. By mixing several species, the final product can be a nearly ‘complete diet’ as long as there is enough control of the conditions of biomass production. However, significant variations of chemical composition of seaweed actually make their use currently challenging, hence the necessity for further research. Regarding microalgae, operating conditions are even more complex, which makes them cost prohibitive. Microalgae fat content is particularly suitable for the biodiesel industry, and many projects are being set up to develop this variety for use in animal nutrition.