Study to assess hemp seeds as aquafeed

Researchers in the UK are looking into hemp – otherwise known as the cannabis plant – as a potential source of protein in aquafeed. Salmon lovers hoping that this might add an extra mood-altering kick to their favourite fish are set for disappointment, however.

Rare Earth Global, growers of industrial hemp for a range of sustainable products, has received £50,000 in funding from the UK Seafood Innovation Fund (SIF) to explore how hemp seeds could be integrated into the diets of farmed salmon in Scotland.

With support from the Sustainable Aquaculture Innovation Centre (SAIC) and the University of Stirling’s Institute of Aquaculture, the project team has begun an initial feasibility trial to assess the impact of hemp protein on fish health and wellbeing, looking at factors such as digestibility and nutritional value.

Researchers from the Institute of Aquaculture will be conducting trials at the University of Stirling’s facilities to assess how salmon react to different varieties of the hemp plant and any impact that the ingredient has on gut bacteria and the digestive system.

Hemp-based protein is already sold for human consumption as a plant-based nutritional supplement as well as being used in cattle and poultry farming, and to produce paper and textiles. However, the results of this study could see locally grown hemp being introduced as a core feed ingredient in aquaculture for the first time.

Initial indications suggest that a protein content of up to 50% could be achieved from the plants grown on UK soil, exceeding producers’ minimum requirements of 35%, as well as reducing the sector’s reliance on imported ingredients such as soy and fish meal.

Hemp and cannabis are biologically the same species of flowering plant, but “hemp” is legally defined (in the US) as a variety that has less than 0.3% of THC (tetrahydrocannabinol), the chemical in cannabis that gives users a “high”. In any event, the plant’s seeds do not contain significant amounts of THC, which is found mainly in the flowers, leaves and stalks.

Rare Earth Global started exploring the idea of using hemp seeds in aquafeed as part of its “zero waste” commitment, ensuring that every part of the plant is used for maximum value.

Suneet Shivaprasad, managing director and co-founder of Rare Earth Global, said: “There are lots of novel feed ingredients coming into the aquaculture sector, but the hemp seed trial is about making the best use of local ingredients. Hemp is one of the fastest growing plants, using minimal water and capturing up to eight times more carbon than most trees, which makes it a highly sustainable choice for so many different products and materials.

“Our aim is to ensure that every part of the plant delivers maximum impact, which is why we are focusing on aquaculture. Our studies show that protein conversion rates in salmon are much higher than for cattle or poultry, highlighting significant potential for the sector to introduce it as a new, sustainable feed ingredient. The process could be scaled up very quickly and we could see an entirely new UK-based supply chain for fish feed emerging in the near future.”

Monica Betancor, lecturer at the Institute of Aquaculture, said: “We already know that hemp protein is suitable for human consumption, which is highly promising, but this trial will help us better understand its impact on fish diets including gut health and digestibility. There may also be additional nutritional benefits, such as anti-inflammatory properties, and our aim is to gather appropriate data that can be used to inform future decisions about the suitability of this new feed ingredient.”

In the US, another project is under way to investigate the use of hemp as an animal feed ingredient. The SUSHI project (Sustainable Use of a Safe Hemp Ingredient) is investigating the potential use of hemp as an animal feed ingredient. The programme is, among other avenues, exploring the potential for hemp in aquafeed.

On 28 July, Brandy E.Phipps – an Assistant Professor in the Department of Agricultural and Life Sciences at Central State University – gave evidence to the Biotechnology, Horticulture, and Research Subcommittee of the US House Committee on Agriculture about the research.

She told the committee: “Establishing hemp as a safe feed ingredient could provide new grain markets for the hemp sector and an economical and environmentally sustainable feed to produce heart-healthy foods.”

Rare Earth Global hemp field, UK