'One per cent decrease in feed use is a savings of 23 million euros for the Norwegian fish farming industry' (Hanne Dvergedal)
This is how scientists found salmon that needed less food to grow
Monday, August 05, 2019, 17:50 (GMT + 9)
Salmon that makes efficient use of its feed is crucial in order to ensure sustainable growth in aquaculture. Hanne Dvergedal in Foods of Norway has discovered a pioneering method to detect the most efficient “bodybuilders”.
With its long coastline and protected, deep fjords, Norway has always been a nation where fish are an important part of the economy, whether wild-caught or farmed.
It is in fish farming, however, where the nation is setting new records. In 2018, for example, Norway exported 10 billion euros worth of seafood, of which aquaculture accounted for about 70 percent of the value.
Although aquaculture is mature as an industry, there is still room for advances in production, particularly when it comes to fish food. Farmed salmon have been bred over the decades to convert feed efficiently, but there is room for improvement, researchers agree.
«The goal is to produce as much fish meat as possible with the least amount of fish feed,» says Professor Gunnar Klemetsdal at the Norwegian University of Environmental and Life Sciences (NMBU).
Finding the most efficient fish
Recently, researcher Hanne Dvergedal was able to identify which salmon individuals use feed more efficiently than others, by analysing the content of specially labeled feed in the salmon's muscles, liver and fat. She recently earned her doctorate on the topic at NMBU.
«This is an important step in our efforts to produce salmon that use less feed,» says Klemetsdal. He was Dvergedal's supervisor and has studied the efficient use of fish feed by salmon for many years.
Breeding for efficiency
Ever since Norway’s aquaculture industry started in the 1970s, scientists have selectively bred salmon with specific characteristics. They have bred fast-growing salmon that are robust and can withstand different fish diseases.
Today's farmed salmon usually can be harvested after about a year, when they weigh about five kilos. But Dvergedal’s discovery suggests this can be reduced even further.
«There is a lot of money to save on feed by getting the salmon up to slaughter weight with the fewest possible feeding days,» Klemetsdal explains.
Feed efficiency and growth
But a large proportion of the genetic variation in how efficient a salmon is in using feed is due to factors other than growth, Klemetsdal says.
For example, some salmon eat more feed than others, but use the extra energy that results to swim more or replace more cells in the body, rather than growing.
«So there is room for improvement,» Klemetsdal says.
Hanne Dvergedal in Foods of Norway has, for the first time ever, successfully documented genetic variations in feed efficiency in Atlantic salmon. Photo Janne Brodin, NMBU
Enhancing feed efficiency of farm animals and farmed fish is one of the main pillars in Foods of Norway’s research, in addition to the development of novel, sustainable feeds.
For the global salmon farming industry the potential for reducing feed costs, increasing feed resource efficiency and minimizing environmental impact is substantial.
The PhD study was performed using 2300 fish at pre-smolt stages in freshwater. Photo Janne Brodin, NMBU
The PhD study was performed using 2300 fish at pre-smolt stages in freshwater.
In 2019/2020, Foods of Norway will carry out follow-up studies to validate the method by using rainbow trout and by performing a large-scale experiment with Atlantic salmon in the ocean.
Source: Nancy Bazilchuk/sciencenordic.com, based on an article by Anne Lise Stranden article here (Norwegian)