Smoltification and transfer to sea is a demanding period for a young salmon. However, a moderate amount of the fungal protein product Pekilo in the feed boosts the immune system and makes the young salmon more robust, according to Dominic Duncan Mensah's doctoral thesis.
Pekilo (Paecilomyces variotii) in salmon feed, focusing on growth performance, gut microbiota, immune responses, fish health and fish welfare in both freshwater and saltwater.
To determine the effect of different levels of Pekilo in the feed, Mensah conducted trials with increasing levels of inclusion. 5, 10 and 20 per cent of the feed protein was replaced by Pekilo. The results from the freshwater trials showed a very good effect on both growth and health, especially at the lower levels of Pekilo.
Mensah is a PhD-student at the NMBU-based centre for research-based innovation, Foods of Norway, but the fungus he is working on is far from a new feed ingredient in the research at the centre. It has already been explored and tested for many years, but mostly on other livestocks. There, it has been shown to provide good growth performance in chickens, pigs and calves. However, there has been a lack of knowledge about the effect of Pekilo on fish.
Positive impact even after smoltification
In one of the experiments, the fish were transferred from freshwater to saltwater and fed for 35 days with the same diets as the fish received in freshwater. The results were measured both as gene expression and protein expression, i.e. how the information contained in the genes is expressed in the cells of the fish intestine after the fish have eaten the different feeds. The analyses indicate that moderate amounts of PEKILO in the feed result in fish that can withstand more stress and are more robust.
Focus on increased sustainability has brought Pekilo out of the storage
Pekilo as a source of protein is not a new discovery, as the Finns were already growing the fungus on residual streams from the paper industry in the 1970s and using it as a source of protein in livestock feed. When the cellulose industry's glory days were over and other protein sources such as soya was put into use, the fungus were placed in storage. But with a new focus on increased sustainability in feed production and increased self-sufficiency in food, Pekilo has been brought back into the light.
The Finnish biotechnology company Enifers Mycoprotein owns the entitlements to Pekilo, and it is pilot factories in Finland that have produced the fungus for the trials at NMBU.
From research to Norwegian industry
A willingness to invest in scaling up protein production in Norway has long been needed. In the autumn of 2025, the first stage of construction will begin on the plant that will convert agricultural by-products into animal feed protein from Pekilo, primarily for fish feed. Sweden's WA3RM and Norway's BIO3 have entered into an agreement to develop a joint production facility at the NorSea Atlantic plant in Averøy. Production takes place under licence from Finland.
Two million tonnes of fish feed are produced annually in Norway, and the first stage of the factory will only produce 30,000 tonnes, so the goal of a volume that works is still some way into the future.
Dominic Duncan Mensah's doctorate is one of many bricks that together lay the foundation for more sustainable feed production, where Pekilo together with other new feed ingredients will reduce the need for imported feed protein in the future.
Dominic Duncan Mensah will defend his thesis at NMBU on 14th of February: ‘Novel Diets and Fish Health: Evaluating the Immunonutritional Impact of Filamentous Fungus Paecilomyces variotii in Aquafeeds for Atlantic Salmon (Salmo salar)’.
Prof Liv Torunn Mydland, NMBU has been the main supervisor.
Co-supervisors have been: Professor Margareth Øverland, NMBU, Dr Byron Morales-Lange, NMBU and Ass. prof. Kartik Baruah, Swedish University of Agricultural Sciences.