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Nofima research uses selective breeding for enhanced growth in microalgae

Nofima scientists have found that selective breeding of microalgae can make them grow faster and increase their omega-3. 

To grow, algae require light, temperature and nutrients but growth is also affected by algae genes. Therefore, scientists tested whether it is possible to breed microalgae like farmed fish. When crossing individuals or genera that produce high yields, the next generation produces higher yields than the previous one, and so on.

The most promising new feed ingredients for farmed fish are found at the very bottom of the food chain, all these make microalgae interesting as a feed ingredient.

“We wanted to know whether breeding can contribute to faster growth and increased omega-3 content. The initial trials we carried out yielded very promising results,” said Marie Lillehammer, Nofima senior scientist.

The research is part of the project NewTechAqua, which is financed by the EU through Horizon 2020 and in collaboration with Universidad de Las Palmas and Ghent University.

Many microalgae reproduce vegetatively. Therefore, the scientists chose the species, Seminavis robusta – a well-studied alga that has sexual reproduction, although not very relevant as a feed resource. Eight lines of the species were crossed with each other in one generation and tested in the breeding trial.

The trial showed that 18 per cent of omega-3 production in the algae is determined by the genes. Breeding gives an 8.8 per cent increase of omega-3 in one generation.

Growth percentages were higher. With a 50 per cent heritability, the microalgae grow 25 per cent faster per generation; in theory, a ninefold increase per year, given ten generations in one year.

“It may be that inbreeding and physiological limitations would halt growth over generations, or growth would have side effects. However, the trial shows that breeding should be explored further if microalgae is to become an important feed ingredient for European aquaculture,” said Lillehammer.