Award details

Novel Omega-3 Sources in Feeds and Impacts on Salmon Health

Reference	BB/S006400/1
Principal Investigator / Supervisor	Professor Johnathan Napier
Co-Investigators / Co-Supervisors	Dr Olga Sayanova
Institution	Rothamsted Research
Department	Plant Sciences and the Bioeconomy
Funding type	Research
Value (£)	240,068
Status	Completed
Type	Research Grant
Start date	01/04/2019
End date	31/12/2022
Duration	45 months

Abstract

We will investigate whether novel omega-3 oils supplying de novo eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) will impact the health of fish fed these oils. Our contention is that these new dietary oils will have effects on lipid and fatty acid metabolism of fish that will, in turn, modulate production of crucial lipid mediators affecting inflammatory responses and immune functions with consequent impacts on resistance to pathogens and parasites. To test this hypothesis, a feeding trial with Atlantic salmon (Salmo salar) will investigate four novel omega-3 oils from macroalgae and genetically-modified oilseed (Camelina sativa) crops supplying DHA alone, EPA alone, or combinations of EPA+DHA, in comparison with traditional fish oils as reference feeds, and omega-3-rich krill oil and omega-6-rich sunflower oil as positive and negative health controls, respectively. Salmon in both freshwater and seawater phases will be subjected to specific pathogen challenges including Aeromonas samonicida, sea lice and amoebic gill disease. The project will provide detailed data on the influence of the novel omega-3 oils on lipid class and fatty acid composition of salmon tissues, and determine the consequences this has on critical metabolic and immune pathways. The insight that these data will provide will, in turn, enable us to elucidate the impact the novel omega-3 oils have on the production of lipid mediators that are crucial in mediating the molecular, mechanisms involved in the inflammatory responses and immune function. The results will enable us to define the positive and negative impacts of novel omega-3 oils on salmon health and welfare, and provide definitive advice on the use of these oils as feed ingredients for farmed salmon.

Summary

Dietary omega-3 fatty acids are key nutrients that have beneficial health effects playing a critical role in the immune system as well as contributing to the normal function of the heart and development of the brain. The human body is unable to produce omega-3, which is why it is important to eat these essential fats. Fish and seafood are unique sources of omega-3 in the human diet, but decline in traditional fisheries means that more than half of all fish consumed is now farmed. Until recently the only way to ensure high levels of omega-3 in farmed fish and seafood was to deliver these nutrients in feeds by using the marine ingredients, fishmeal and fish oil. However, paradoxically, they too are derived from marine fisheries that are at their sustainable limit making them finite and limited resources. The rapid expansion of fish farming in the last two decades has ony been possible with increasing dilution of the traditional marine ingredients with more economical alternatives, primarily plant meals and vegetable oils that lack the omega-3 fatty acids found in fish. Therefore, the development of these alternative feeds in Atlantic salmon (Salmo salar) farming has seen levels of omega-3 in farmed salmon halved in recent years. Dietary omega-3 are equally essential for the health of fish, just as they are for humans. Several negative issues related to farmed fish performance and health have paralleled the development of alternative, low marine feeds with reduced levels of the beneficial omega-3, including higher incidence and severity of inflammatory diseases. However, in addition, inflammation is a key component of the immune response to all pathogens, including parasitic, bacterial and viral infections and so the current low levels of omega-3 in feeds for farmed fish has had consequences for fish health and welfare. Thus, the dual impacts of reduced dietary omega-3 levels on fish health, and the nutritional quality of farmed fish products for human consumers has meant that fish farming, especially of salmon, has spearheaded efforts to both highlight and close the gap between supply and demand for the key omega-3 nutrients. Specifically, the Global Salmon Initiative announced a tender for commercial organisations to supply up to 200,000 tons annually of novel omega-3-rich oils. In addition, a consortium including The World Bank, announced the F3 (Fish Free Feed) Fish Oil Challenge to create a fish-free 'fish oil' substitute. Consequently, new sources of omega-3-rich oils from marine microalgae and genetically-modified oilseed crops have been developed and tested as feed ingredients for farmed fish, including salmon. While these studies have proved the effectiveness of these new oils in increasing omega-3 content of farmed fish, the impact on fish health has been neglected. This project will directly investigate the important health impacts of entirely novel omega-3 rich oils as feed ingredients for farmed Atlantic salmon. The studies will focus on determining not only impact of the new omega-3 sources on the response of salmon to specific disease and parasite challenges, but also on defining the biochemical and molecular mechanisms underpinning fish health, quantifying the potential of these new dietary oils for use in UK salmon farming. The proposal is timely and highly relevant and appropriate as it responds to current needs with cutting edge research to improve the quality and effectiveness of modern alternative feeds in fish farming, enhancing production and feed efficiency, while maintaining the health and improving the nutritional quality of farmed fish, delivering greater sustainability and food security.

Impact Summary

Outcomes will impact at many levels including the salmon feed and production industries, consumers and the general public, in addition to academia. Primary exploitation will be through development and production of novel sustainable feed formulations utilising entirely new de novo sources of the omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA), EPA and DHA, as replacements for the dwindling and expensive marine ingredients, fishmeal and especially fish oil, currently used in UK aquafeeds. The project will therefore provide industry with a new strategy with huge potential to improve the nutritional quality of farmed fish and, in turn, the economic viability and sustainability of UK aquaculture. Tangible outcomes will be the development of more sustainable feeds formulated with very low marine ingredients, but without the negative impacts on n-3 LC-PUFA levels in farmed salmon, expandable to all sectors of the aquaculture industry. However, our exploitation strategy will be far wider than just the feed sector, as we will target fish production industries as a whole, and increase awareness of the potential of new ingredients supplying high levels of EPA and/or DHA to mitigate fish health and product quality issues currently associated with existing sustainable feed formulations. There are two main beneficiaries, the UK salmonid farming, and aquaculture feed industries. The aquafeed industry itself will play a key central role in the commercial application and uptake of the omega-3 sources with our industrial project partner, BioMar taking a lead role. All partners, Universities of Stirling (UoS), Aberdeen (UoA), Highlands and Islands (UHI) and Rothamsted Research (RRES) have worked extensively with BioMar for more than a decade, collaborating on several research studies including BBSRC IPA, BBSRC-NERC and BBSRC Super Follow-on-Funding projects, and PhD CASE studentships. Moreover, UoS and UoA have long established histories as centres of excellence forfish nutrition and health research and are recognised as trusted sources of independent research. All four partners have extensive links with all sectors and key stakeholders in the UK aquaculture industry that involve regular direct contact, engagement and discussion. Thus, we will use these well-established links, along with the support of the industry-led Scottish Aquaculture Innovation Centre (SAIC), to engage with potential end-users including major fish farming companies, to ensure industry-wide dissemination and engagement. Currently, all partners have joint projects with industrial partners at all levels of the industry and these direct links are ideal for a two-way flow of information, and actively involving and engaging end users, stakeholders and beneficiaries, seeking their input throughout the project. UoS, UoA and UHI membership of ARCH-UK (BBSRC-NERC aquaculture Research Hub-UK) involves both Government and HEIs, knowledge will be rapidly disseminated to relevant stakeholders and used to develop further collaborations and strategic initiatives. Tocher and Martin lead ARCH-UK Working Group 1 on finfish nutrition. Communication of issues relating to human health, such as farmed fish and dietary omega-3 will be effected through existing contacts directly in Government (e.g. Food Standards Agency, the Scottish Executive and UK Government), and through various pan-Governmental food security initiatives that we are involved with. Results will be published as usual in scientific peer-reviewed literature (conference proceedings and papers in high impact journals), but also disseminated widely to industry through contributions to trade and professional magazine articles and online sites such as FISHupdate, and the public via Institutional web pages and social media, as well as mainstream media articles and interviews in local and national press.

Committee	Research Committee A (Animal disease, health and welfare)
Research Topics	Animal Health, Animal Welfare, Immunology
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	Industrial Partnership Award (IPA)

Associated awards:

BB/S005919/1 Novel Omega-3 Sources in Feeds and Impacts on Salmon Health

I accept the terms and conditions of use (opens in new window)

export PDF file

back to list new search