Hemp salmon feed project moves forward 

A team of UK researchers is taking the next steps towards using hemp seed as a sustainable protein source for Scottish salmon feeds, following the success of the first live trials.

Rare Earth Global, the company behind the initiative and growers of industrial hemp for a range of sustainable products, has received more than £260,000 in funding from the UK Seafood Innovation Fund (SIF) for a full-scale research and development project which will include a two-month feed assessment.

A feasibility study conducted last year set out to explore how hemp seeds could be integrated into the diets of farmed salmon in Scotland. The team tested two types of hemp meal against a range of factors such as digestibility, fish growth, and the effect on gut health, finding that the ingredient had a comparable nutritional profile with soy and fishmeal – the most common protein sources for feeds.

Fish performance

The next stage of testing involves monitoring how fish perform over the long term when fed hemp seed protein as part of their diet, with the company also supported by the Sustainable Aquaculture Innovation Centre (SAIC) and the University of Stirling’s Institute of Aquaculture (IoA). Salmon farmer Mowi, which has a feed plant at Kyleakin on Skye, will support the formulation and production of the feed, while farmers in Angus and Aberdeenshire will grow the crops.

The research team is aiming to understand the viability of hemp meal protein for commercial inclusion and to discover whether an optimum composition can be identified that delivers the best nutritional results for salmon, as well as testing secondary ingredients used as part of the feed. Another element of the project will cover sustainability, identifying methods for hemp farmers, feed companies and seafood producers to measure the carbon footprint of the entire process.

Zero-waste approach

Suneet Shivaprasad, director and co-founder of Rare Earth Global, said: “The first feasibility trial returned positive results for the viability of hemp seed protein as a core aquaculture feed ingredient, and we are now testing whether it could be included on a commercial scale. Further research will enable us to look at a range of other factors over a longer time period, with the aim of demonstrating that this novel protein can be a success.

“Locally grown, plant-based ingredients are already more environmentally friendly than any imported soy or fishmeal but our zero-waste approach to growing it also ensures that every part of the hemp plant is used for maximum value. In this case, the seeds will be used as a protein source for aquaculture, while the stalks will be used for sustainable construction materials, bioplastics, and bioenergy feedstocks.”

The Collaboration prize in this year's Aquaculture Awards was awarded to Rare Earth Global and the IoA for their feed trials.

At a SAIC-organised aquaculture sustainability summit in Glasgow in May, Shivaprasad said hemp seed protein could be a 1:1 replacement for soy. “Growing locally will reduce CO₂ content by 41%,” he told the summit.

Two tonnes per hectare

Up to two tonnes of hemp seed can be produced per hectare of the crop, and Rare Earth Global is working with a range of farming cooperatives and family run farms – including farmers in Scotland, Yorkshire, Lincolnshire and Hertfordshire – to develop the supply of the raw material throughout the UK.

We hope to prove that hemp protein can serve as a direct replacement for soy in terms of digestibility, nutrition, and growth

IoA associate professor
Monica Betancor

Last summer, the UK Government published its Hemp-30 roadmap – a 10-year strategy to make industrial hemp a major UK crop. It is estimated to add around £700 million to the economy and sequester or displace one million tonnes of carbon dioxide each year.

Monica Betancor, associate professor at the University of Stirling’s Institute of Aquaculture, said: “By conducting a two-month feed trial we hope to prove that hemp protein can serve as a direct replacement for soy in terms of digestibility, nutrition, and growth. From what we have seen already, it has only had a positive impact on the salmon involved in our first trials.”

UK supply chain

Sarah Riddle, director of innovation and engagement at SAIC, said: “It is great to see the research team taking the development of a new plant-based feed to the next stages.

“There are opportunities here for new UK-based supply chains to emerge, reducing our reliance on imported ingredients and lessening the overall environmental footprint of aquaculture while increasing its economic contribution. It is also highly positive to see a company that is new to the aquaculture sector collaborating with world-class researchers and major producers to turn an innovative idea into a reality."