In an innovative leap for sustainability, researchers from the Norwegian Institute of Bioeconomy Research (NIBIO) are exploring the potential of grass as a protein-rich ingredient for fish feed, aiming to reduce the country's reliance on imported soy and to promote a greener salmon aquaculture sector.

While grass is a staple in cattle diets, it is seldom considered for aquatic animals. However, NIBIO scientists assert that biorefining grass could yield a locally produced fish feed that rivals the nutritional quality of traditional ingredients like soy. This cutting-edge approach could revolutionize the industry by optimizing local resources and enhancing fish nutrition.

Located in Steinkjer, Norway, NIBIO's newly launched pilot plant is capable of processing an impressive 2.5 metric tons of fresh grass per hour. The facility is not just a production hub but a research platform for experimentation with feeding practices and overall system development. According to Steffen Adler, a research scientist at NIBIO, the initiative seeks to tackle Norway's heavy dependence on imported feed, particularly for species like salmon that require high-quality protein.

"Our goal is to explore local sources of protein for salmon farming, including grass and macroalgae, and to develop effective processing methods that ensure a balanced nutrient profile," Adler stated.

The biorefining process initiates with the collection and mincing of fresh grass, which is then pressed to extract a nutrient-rich juice and a fibrous pulp. The result is a grass protein concentrate with around 40% protein content, along with a brown liquid known as grass whey, rich in essential nutrients compatible with aquaculture needs.

Gjermund Bahr, a senior advisor at NIBIO, emphasizes the urgent demand for new feed materials across various sectors, not just aquaculture but also poultry and livestock. "Grass is abundant and underutilized; refining its protein could provide a valuable amino acid profile for fish species like salmon," he noted. However, further studies are required to confirm its efficacy specifically for salmonids.

While grass feeds have shown promise in other fish species, additional research is needed to assess their impact on salmon growth, health, and product quality. Initial studies in Denmark and Germany have shown that including grass protein in the diets of species like rainbow trout is feasible, but exploring effects on crucial factors like flesh color and fat composition is essential.

Interestingly, initial experiments with chickens fed grass protein concentrate revealed changes in fat color, hinting at potential effects in fish as well. "We need to understand how grass protein influences feed intake, fat distribution, and even flesh pigmentation," Adler explained.

Research from feed producer Aller Aqua reinforces the initiative, with ongoing trials to evaluate the grass protein's nutritional viability for Atlantic salmon. Dr. Florian Nagel, head of research at Aller Aqua, emphasizes that local sourcing of feed ingredients aligns perfectly with sustainability goals, potentially reducing the carbon footprint of aquaculture while ensuring fish receive nutritious feed.

Norway's heavy reliance on imported feed—over 90%—poses a challenge, especially in times of international uncertainty. Bahr believes that diversifying feed ingredients domestically is crucial for the industry's future. "While grass can't entirely replace soy protein due to differing protein levels, its amino acid profile is excellent, and we are committed to finding ways to incorporate it effectively into salmon diets," he said.

Both Adler and Bahr express optimism about the future of grass protein in aquaculture. NIBIO plans to continue refining the grass protein concentrate, conducting tests to optimize its quality, and investigating additional biorefining products such as grass whey. They are confident that grass protein could play a pivotal role in transforming aquaculture feed, providing a sustainable alternative while ensuring fish health and performance.

By harnessing advancements in grass protein biorefining, Norway may soon experience a sea change in aquaculture, dramatically enhancing self-sufficiency and sustainability while paving the way for a more robust domestic fish feed industry. Stay tuned as this groundbreaking research continues to unfold—could grass be the key to a greener future for salmon farming?