Will grass-based feed help make salmon farming more sustainable?
Norwegian researchers are exploring whether grass can be turned into a protein-rich fish feed ingredient to reduce reliance on imported soy and lower aquaculture’s environmental footprint.
The Norwegian Institute of Bioeconomy Research (NIBIO) has opened Norway’s first green biorefining pilot plant in Steinkjer, capable of processing 2.5 metric tons of fresh grass per hour. Scientists believe that grass protein concentrate could offer a locally sourced alternative to traditional feed ingredients.
“A lot of feed is imported, so our work opens up the possibility of a domestically produced feed,” NIBIO research scientist Steffen Adler said in an article published on the Global Seafood Alliance site. “We are looking for local protein that could be used in salmon farming.”
Unlocking Potential
The biorefining process extracts protein-rich juice from fresh grass, yielding a concentrate with approximately 40 percent protein. While promising, more research is needed to determine its suitability for salmon.
“There is a great need for new feed materials, not only in aquaculture but also in chicken and other livestock production,” said Gjermund Bahr, senior advisor at NIBIO. “If refined properly, grass protein has a good amino acid profile that may be suitable for salmonids.”
However, questions remain about its impact on fish health, growth, and flesh color.
“Feeding experiments with chicken that were fed grass protein concentrate found that their fat became yellower,” Adler noted. “The same could happen if we feed grass protein to fish.”
A Step Toward Feed Independence
Norway currently imports more than 90 percent of its aquafeed ingredients. A local alternative like grass protein could improve self-sufficiency and sustainability.
“When it comes to grass, words such as high sustainability or low carbon footprint will bring fish farms and feed companies on board immediately,” said Bahr. “But it’s currently not possible to completely replace soy protein with grass. Its protein content is too low, though it has a good amino acid profile.”
Aller Aqua is conducting feeding trials to assess grass protein’s nutritional suitability for Atlantic salmon.
“We need raw materials that meet the nutritional requirements of farmed fish,” said Dr. Florian Nagel, head of research at Aller Aqua. “Grass could reduce aquaculture’s CO2 footprint and dependency on raw material imports, but first, we need to confirm its effectiveness.”
NIBIO plans further trials to refine the protein concentrate and assess its large-scale feasibility. While full replacement of conventional ingredients may not yet be possible, researchers see grass protein as a step toward a more sustainable salmon industry.
