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Aquaculture

HUGE BREEDING POTENTIAL IN MICROALGAE

HUGE BREEDING POTENTIAL IN MICROALGAE

Huge breeding potential in microalgae. Scientists have now shown that microalgae can grow faster and form more omega-3 if bred. This makes them even more interesting as a feed ingredient.

At the very bottom of the food chain, we find the most promising new ingredients for feed for farmed fish. Including microalgae. Ingredients at the bottom of the food chain are generally promising, because less energy is lost if used directly in fish feed than if they go through, for example, krill and small fish on their way to the salmon gap.

Marine omega-3 fatty acids are important nutrients in fish feed, of which fish oil is the main source today. If we can grow microalgae with a high enough level of these fatty acids, it will be easier to phase out fish oil in the feed.

Pioneer: Showing that breeding is possible

In order to grow, the algae are affected by light, temperature and nutrients. But growth is also affected by the genes of the algae. Therefore, the researchers tested whether one can breed on microalgae as one does with, for example, farmed fish: When targetedly crossing individuals or genera that have high performance, the next generation gets higher performance than the previous ones, and so on.

“We wanted to know whether breeding can contribute to faster growth and increased omega-3 content. The initial trials we carried out with our partners yielded very promising results,” says Senior Scientist at Nofima, Marie Lillehammer.

They are probably the first to calculate genetic variation in microalgae.

Many microalgae reproduce by cloning. Therefore, the researchers chose the species Seminavis robusta – a well-studied algae that has gendered reproduction. Eight lines of the species were crossed with each other in one generation and tested in the breeding experiment.

25 percent increase in one generation

Although the species is not considered particularly relevant as a feed resource, the experiment showed that 18 per cent of omega-3 production in the algae is determined by the genes (degree of heredity). With breeding, that means an 8.8 percent increase in omega-3 in one generation.

For growth, it will be even bigger numbers. With an inheritance rate of 50 percent, the microalgae grows 25 percent 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 have halted growth over generations, or growth would have side effects. But the experiment shows that breeding should be explored further, if we want microalgae to become an important feed ingredient for European aquaculture,” says Lillehammer.

The research has been part of the EU project NewTechAqua, and has been carried out in collaboration with the University of Las Palmas in Spain and the University of Ghent in Belgium.

Image: Now it has been shown that breeding can significantly increase the omega-3 content of microalgae. Marie Lillehammer is behind the research. Photo: Jon-Are Berg Jacobsen © Nofima.

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