Alternative aquafeed sources can meet omega-3 demand

Using algal oil in aquafeed provides a rich source of Omega-3 fatty acids, addressing one of the main limiting factors to the growth of the aqua industry while also reducing its reliance on marine ingredients.

Alternative aquafeed sources can meet omega-3 demand
Ian Carr
Senior Director, Global Business Development

In recent decades, there has been an increasing demand for fish as a key source of protein in human diets with an ever greater proportion of fish being supplied through aquaculture. However, the aquaculture industry faces a huge challenge due to the scarcity of fish oil. Currently, the world’s limited amounts of wild capture fisheries are insufficient to provide the required essential fatty acids for aquafeed, and demand for farm-raised fish is set to continue rising. This article reviews the nutritional importance of Omega-3 fatty acids in fish and humans and how using algal oil as an alternative source of Omega-3 can play an important role.

The Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential for human health. They are known to reduce the risk of cardiovascular disease and are important contributors to a healthy and nutritious diet. Their primary sources are oily fish, including Atlantic salmon, which is rich in both EPA and DHA. Omega-3 fats are also equally important for fish health. However, they are not produced in sufficient quantities by the fish themselves and need to be supplemented in aquaculture feeds.

The Atlantic salmon industry must continue to grow to meet the increasing global demand for healthy seafood. However, the overuse of marine resources needed to produce fish oil, the original lipid source in salmon aquafeeds, has become a bottleneck. Vegetable oils are used as alternative lipid sources, but these are rich in Omega-6 and deficient in Omega-3 fatty acids. Because of this, EPA and DHA levels in salmon fillets have decreased by more than 50% in recent decades, which is detrimental for both farmed salmon and humans alike.

Vegetable oils in feed also unbalance the optimum Omega-3 to Omega-6 ratio that is essential for fish and human health. the increasing ratio of Omega-6 fatty acids to Omega-3 creates a dietary imbalance that can negatively affect fish performance and welfare. In fact, research suggests too much Omega-6 compared to Omega-3 can reduce the benefits of the latter.

Microalgal oil from Veramaris is a viable alternative ingredient for fish feed owing to its richness in EPA and DHA, ease of integration into fish feed formulations, and environmental sustainability, resulting in a much lower marine footprint for salmon farming.

Replacement of fish oil with algal oil has been documented in rainbow trout, gilthead seabream, and Atlantic salmon, but until now comprehensive studies covering the full life-cycle were lacking. To address this gap, a series of experiments were conducted to assess the impact of the partial and entire replacement of fish oil with algal oil from Veramaris in all life stages of the Atlantic salmon.

When tested for growth, muscle fatty acid profile, and muscle quality, the experimental fish were found to be healthier and more nutritious. They also showed greater than 96% EPA and DHA digestibility in response to the altered diet. The inclusion of algal oil instead of fish oil led to a huge reduction in the marine footprint of the farmed salmon. Additionally, higher EPA and DHA levels mean that consumers can attain recommended intake levels by consuming just one portion of salmon per week, consistent with advice from national health authorities.

Moreover, the pigmentation and sensory characteristics of raw fish fillets were maintained intact suggesting that the replacement of fish oil with algal oil is not likely to affect consumer preference. With its ease of integration into fish feed, Veramaris microalgal oil has become a viable alternative for addition to aquafeed.

While scientists typically determine the dietary needs of fish based on development, they rarely consider challenging farm conditions during lifecycles. EPA and DHA requirements are higher for salmon, for instance, when they are held in more challenging conditions. Likewise, the ratio of DHA to EPA changes through the lifecycle. As a result, the amount and type of essential fatty acids in aquafeed are important to the performance and welfare of fish.

The Optimum Omega Nutrition™ guidelines developed by Veramaris help farmers provide peak health, welfare, and performance at each stage of growth. Optimum Omega Nutrition™ by Veramaris is a guideline for meeting EPA & DHA Omega-3 and ARA Omega-6 requirements, while maintaining the correct Omega-3 to Omega-6 ratio in fish and shrimp diets, leading to improved health and welfare throughout production.

By using Veramaris natural marine algal oil in conjunction with the Optimum Omega Nutrition™ guidelines, fish farmers not only stand to improve productivity, product quality and yield but also lower their marine footprint.

• Santigosa E, Olsen R E, Angelico Madaro A, Trichet V V, Carr I (2023) Algal oil gives control of long-chain omega-3 levels in the full-cycle production of Atlantic salmon, without detriment to zootechnical performance and sensory characteristics. DOI: 10.1111/jwas.12947
• Carr I, Glencross B and Santigosa E (2023) The importance of essential fatty acids and their ratios in aquafeeds to enhance salmonid production, welfare, and human health. Front. Anim. Sci. 4:1147081. doi: 10.3389/fanim.2023.1147081

About Ian Carr
Ian is passionate about sustainable aquaculture and experienced in aquafeed innovation, marketing and sustainable development from earlier roles with EWOS, Cermaq and Cargill. He currently leads Global Business Development for Veramaris, an innovator of omega-3 oil from fermented algae . He holds an MBA from the University of Strathclyde in Glasgow, Scotland and has also studied fish farming. “I believe aquaculture has a bright future,” says Ian. “Veramaris helps farmers to produce healthier fish and more sustainable seafood for people to enjoy.”