Millennial Salmon Project: Omega-3 ingredient improves feed sustainability and quality

The liquid suspension can be used at varying inclusion levels and up to three times the industry standard with high retention of omega-3 fatty acids, feed quality, digestibility, supporting sustainable growth in the aquaculture industry, finds a study.

The research was conducted under the Millennial Salmon Project​​, a strategic partnership among organizations along the value chain of salmon production.

Primarily funded by the Research Council of Norway and made up of leading organizations Nofima, InnovaFeed, Corbion, Cargill, MOWI, Labeyrie Fine Foods, SINTEF Ocean and Auchan, that industry alliance aims to improve the sustainability of farmed salmon through focusing on the circular economy and by using novel ingredients with a low carbon footprint.

In tandem with their evaluation of Corbion’s AlgaPrime DHA LS, the partners are assessing InnovaFeed’s Black Soldier Fly (BSF) derived protein meal in feed for Atlantic salmon.

According to a recently published paper in Aquaculture​​, the researchers sought to determine optimal inclusion levels of Corbion’s omega-3 product — a dried and fine milled microalgae (Schizochytrium sp.) biomass suspended in rapeseed oil — in salmon feed mixes prior to extrusion and in the post drying vacuum coating step, evaluating the ingredient’s effect on the feed production process. Variables examined included: physical pellet quality, expansion parameters and microstructure and later its digestibility.

The team produced and assessed a range of diets from a control feed using fishmeal and soy protein concentrate to feeds with high inclusion levels of the omega-3 ingredient.

Findings ​

The findings indicate that Corbion’s product can be added to salmon feed at varying levels without negatively impacting feed quality while also promoting a more stable process and boosting pellet quality. The researchers also saw that nutrient digestibility is not affected by AlgaPrime inclusion prior to extrusion or in the coating step.

In addition, the team determined that inclusion of 100g/kg AlgaPrime DHA LS in the mixture was optimal.

Pellet impact ​

AlgaPrime can seamlessly integrate into fishmeal or soy protein concentrate-based diets prior to extrusion, exerting minimal impact on hardness, Doris durability, and pellet water stability index, concluded the researchers. The introduction of AlgaPrime enhances the lipid content of the feed mix, serving as the primary catalyst for the observed variations in viscosity, expansion, and microstructure responses. Lower lipid levels in the feed mix led to flow instabilities, larger pores in expanded pellets, floating feeds at the target lipid level, and increased oil leakage, they noted.

The incorporation of AlgaPrime/lipid elevates feed melt plasticity and enhances mixing performance, fostering a more stable process with reduced pellet expansion, they said.

The chosen experimental extruder and dryer settings demonstrate no significant loss of omega-3 fatty acids during processing steps. Pellet pores for the centroid feed prove sufficiently large to adsorb a substantial amount of AlgaPrime suspension in the vacuum coating step, without causing a notable change in oil leakage, reads the study.

The AlgaPrime processing method enables the product's utilization without necessitating additional cell wall rupture or thermomechanical treatment in the extrusion process, and this capability allows for coating the product at high inclusion levels in feeds for Atlantic salmon without adversely affecting apparent nutrient digestibility, reported the researchers.

Debottlenecking program​

AlgaPrime is grown via a closed fermentation system, using sugarcane.

Along with continued expansion in the aquaculture market, the firm sees growth opportunities​​ for its omega-3 business in the higher margin pet and human nutrition sectors due to increased market demand and limited fish oil supply.  

Corbion has been investing in its algae fermentation facility​​ in Orindiuva, Brazil to ensure process optimization. The plant, acquired from TerraVia six years ago, was initially only designed to manage one product. But Corbion ran a debottlenecking program at the Brazilian facility to gain more output and more flexibility, and to allow it run multiple lines to cope with the growing demand from food, feed and pet markets for omega 3, Corbion algae ingredients president, Ruud Peerbooms, told us last year.

The company's R&D team in San Francisco is focused on algae strain development and fermentation work, screening thousands of algae strains to identify those that are highly productive, efficient, palatable, and nutritious. Those experts want to optimize algal yield strain and explore what additional products could be derived from algae: proteins, other lipids as well as antioxidants.