New research to improve sustainability and security of supply of aquafeed ingredients

Abstract

Fish farming in the UK and Europe is dominated by carnivorous species, salmonids and marine fish, and so feeds have traditionally been based on fishmeal and fish oil that have satisfied both the nutritional requirements of the fish and the consumers’ demands for healthy and nutritious products. This practice is becoming increasingly unsustainable due to the limited, finite supply of these marine resources. Consequently, alternatives to fishmeal and fish oil have been actively researched over the last decade with the Nutrition Group at the University of Stirling’s Institute of Aquaculture at the centre of research in the UK and Europe. The primary focus in Stirling has been alternatives to fish oil, which reduces to alternative sources of the essential n-3 or “omega-3” long-chain polyunsaturated fatty acids (LC-PUFA). Unfortunately, there are currently no commercially viable alternatives to fish oil as sources of these fatty acids and so the only option has been the use of vegetable oils that can be rich in PUFA but are devoid of omega-3 LC-PUFA. However, the fish’s nutritional requirements for omega-3 LC-PUFA can be met with relatively low dietary levels, and so it is possible to replace up to 100 % and around 70% of fish oil in feeds for salmonids and marine fish, respectively, provided their essential fatty acid requirements are met by other dietary components like fishmeal. However, this high level of replacement impacts on the omega-3 LC-PUFA content of the flesh and can compromise the health-promoting properties of the products, and so resolving this issue is actually the challenge that aquaculture has faced.