A new way to optimise fish feed and improve fish farming

Luke's experts improve the traits of farmed fish through selective breeding. SPAROS' experts develop fish feeds and software to optimise feed development. Together, we created a bio-mathematical model that allows feed mills and fish farmers to predict the nutritional needs of current and future fish and ensure more efficient and sustainable farming.

In fish farming, the main goal is that fish stay healthy and use feed efficiently for growth. In this way, the costs and environmental impact of fish farming also remain as low as possible.

Our experts at the Natural Resources Institute Finland (Luke) have supported fish farming by breeding fish for 40 years. We select healthy specimens that grow better than others with the same amount of feed. The best specimens also tend to use dietary protein for muscle growth rather than fat gain.

As the genetic traits of fish change, so do their nutritional needs. But how? Little attention has been paid to this, although optimised nutrition would improve the well-being of fish and the efficiency of fish farming.

— Antti Kause, principal scientist at Luke

"Fish farmers usually choose their feed based on the fish species and the conditions at the fish farm. Fish feed is not specifically adapted to genetic changes in the fish strains", confirms Tomé Silva, a nutrition researcher. He works at SPAROS, a Portuguese company, which researches fish nutrition and develops fish feeds for specialised purposes.

Kause and Silva tackled the interaction between genetics and nutrition in this joint project, which was part of the EU project AquaIMPACT led by Luke. Now they can predict how the nutritional needs of fish will change as a consequence of genetic trait changes due to selective breeding.

The AquaIMPACT project focuses in particular on Atlantic salmon, rainbow trout, gilthead sea bream and European sea bass, but the results can be applied to almost any fish species, according to Kause.

Mathematical models to predict nutritional needs

"We created together a set of mathematical models that allow us to convert information from breeding programmes into nutritional recommendations. We can look at the impact of changes in different traits of fish separately or together," Silva says. Modelling was a familiar task for both SPAROS and Luke.

"We had a very similar, mathematical way of thinking, which made cooperation easy. It was a bit more demanding to get the thoughts of the geneticist and the nutritionist on the same lines, but, through ups and downs, we succeeded in that too. We were able to combine the experience that had accumulated in both organisations over decades," Kause says.

"Our collaboration was very fruitful and important. We try to predict future nutritional challenges, so that we are ready to tackle them when the need arises," Silva says. SPAROS can now use the mathematical models developed in the project in its software, which the company and its customers use to optimise fish nutrition and feed development.

Silva finds the genetics perspective very interesting in a field that is developing at a fairly fast pace. In terms of raw materials, the focus of fish feed has shifted in a few decades from fishmeal and fish oil to plants, and now other alternative feedstuffs, such as microbes, algae, insects and side streams of the food industry, are also attracting attention.