Salmon need to be fed without harming the environment. The solution to this is a small yeast fungus that can be cultivated from timber, as well as a range of raw materials that would otherwise be discarded.
Pekilo (Paecilomyces variotii) is a filamentous microbe that can help combat deforestation in South America and reduce greenhouse gas emissions from transportation. Salmon seem to enjoy eating it too.
“The fish immediately liked the feed. The salmon spent no time getting used to the taste. It’s not often we see things go quite so well,” says Jamie M. Hooft.
Need to do something about feed
Hooft is a researcher at NMBU. Since 2015, the university at Ås has been leading a large, international centre to find more sustainable feed, not only for farmed salmon, but also for livestock.
“If we are to achieve our climate targets, we need to do something about feed, and that means looking at sustainable ingredients,” says Professor Margareth Øverland, head of the centre, Foods of Norway.
Scientists, businesses and organisations have now progressed from not only developing the new feed – they have also begun testing the feed on salmon.
Good growth performance and health
“We have conducted growth trials in which we have given the salmon feed containing varying amounts of Pekilo,” says Hooft. Up to 20 per cent of the protein content in the feed has been replaced with Pekilo. The researchers measured and weighed whole fish before and after feeding, and assessed the feed’s digestibility in order to see what the fish absorbed and converted into muscle. They also studied gut health to assess whether Pekilo has an effect on health and the immune system.
The results have been positive throughout the trials. The salmon take up more protein when consuming feed containing Pekilo. This is good for the environment because more of the feed is utilised. It means that the salmon can grow equally well with a little less feed, resulting in less of a carbon footprint.
“It also results in improved growth in the long term, in addition to reducing emissions of nitrogen and phosphorus,” says Øverland. The gut health studies indicate that the Pekilo feed has a positive health effect.
Deforestation and transportation
Why spend so many resources on developing a new type of feed for farmed salmon? The answer is in the numbers. The world needs more food, and in Norway, salmon and trout production could increase fivefold between 2020 to 2050. That would require 6.2 million tonnes of feed – that’s more than the weight of the Great Pyramid of Giza.
Ninety-two per cent of salmon feed is currently being imported from other parts of the world, not least soya from Brazil. We need new ingredients that have a small climate footprint, not only to increase the security of supply, but also to meet Norway’s climate targets. There needs to be strict climate requirements for the raw materials that are imported. The Pekilo feed proves to result in significantly lower greenhouse gas emissions than soya.
Insects are another source of protein that many people are discussing and researching, not least because they are said to be environmentally friendly and easy to produce. However, it has been shown that feed made using insects produces more greenhouse gas emissions than feed made with Pekilo.
High cost
For the aquaculture industry – and the end consumer – cost is important. Buying feed accounts for almost half of the cost of salmon production.
Pekilo can be produced throughout the year and does not require large areas of land or good weather. The filamentous microbes are produced in a process that is very similar to brewing beer, with the yeast growing in tanks.
Norwegian spruce can be used as a raw material, as can a number of by-products from sea and land.
“Now everybody’s just waiting for something to happen. We possess a wealth of knowledge, but that knowledge needs to be taken further and the technology needs to be scaled up,’ says Øverland. The rules also need to change: they currently prohibit many potential raw materials from being turned into good fish feed.
Starting with timber
Timber will initially be used to move to a larger scale. “The sustainable biorefinery Borregaard produces ethanol from timber and is then left with a residual fraction. That’s what we use as an input to produce the new microbe,” she says.
“We possess a wealth of knowledge, but we still need to develop the technology, and there is a lack of capital to make the required investment,” says Øverland.
Reference:
Jamie M. Hooft et al: Paecilomyces variotii (Pekilo) in novel feeds for Atlantic salmon: Effects on pellet quality, growth performance, gut health, and nutrient digestibility and utilization. Aquaculture, 2024, doi: 10.1016/j.aquaculture.2024.740905