FutureEUAqua and sustainable innovative tailor-made fish diets

The ongoing positive growth trend of the aquaculture industry continues, reflecting the rising demand for healthy human food products. Availability of sustainable ingredients in fish feeds is crucial to maintain the increasing demand of the aquaculture industry and the consumers. In FutureEUAqua, resilient fish, efficient in utilizing sustainable innovative tailor-made diets are developed.

European aquaculture production has reached 1.3 million tonnes in volume with a value of over 4 billion euro (EU-28 member states). Of this amount, 4% is certified as organic, amounting in 2015 to a total of approximately 50,000 tonnes (Lembo and Mente, 2019). Nevertheless, significant bottlenecks present in organic farming need to be overcome in order to maintain this positive trend. In 2015, EU consumers spent 54 billion euro for buying fisheries and aquaculture products, reaching the highest amount ever recorded (EUMOFA, 2017).

However, Europe is still heavily dependent on external markets to cover this demand. Thus, EU aquaculture needs to increase the competitiveness of its products and respond to consumer demands for high-quality and safe food, in a challenging context of climate change, greater competition for natural resources, and conflicting interests for space and markets. To ensure food and nutrition security by 2030, the food production sectors have to sustainably expand in terms of space use, production and new value chains, exploring and enhancing innovation opportunities offered by sustainable and resilient aquaculture production systems, implementing the circular economy principles and increasing social acceptance of the corresponding activities and products.

The ongoing positive growth trend of the aquaculture industry continues, reflecting the rising demand for healthy human food products. Availability of ingredients in fish feeds is crucial to maintain the increasing demands of the aquaculture industry and the consumers. However, fish performance, health status and final product quality (Kousoulaki et al., 2016) may be jeopardized when substituting dietary fishmeal by alternative ingredients of lower nutritional value.

Thus, new fish feeds and feeding strategies and the exploitation of the genetic potential of farmed fish, by selective breeding in using and transforming more efficiently the dietary component to the necessary essential nutrients, provides great potential and may allow safer larger steps in the progress of achieving sustainable and resilient fish farming practices. Therefore, the onus is on the aquatic nutritionist to select and test ingredients, design formulations for commercially relevant tailored-made aqua feeds for the European aquaculture ensuring high performance, maintaining or enhancing nutritional value and environmental friendliness (Mente et al. 2019).

In FutureEUAqua, resilient fish, efficient in utilizing sustainable innovative tailor-made diets are examined (Figure 1) for the two main aquaculture species, salmonids and marine Mediterranean fish. FutureEUAqua will finetune feed formulations for smart, optimised and better performing conventional and organic aquaculture. Ingredients and tailored made potentially low eco-footprint aqua feeds will be selected, ensuring higher fish performance, nutritional quality, and safety. How can we improve feed to ensure optimal nutrition, safety and performance?

The aqua farming production of salmonids in the EU is the most valuable commercial species, accounting for about 45% of the value of total aquaculture output (Eurostat, 2019). Being a rapidly expanding sector, it places enormous pressure on the aquaculture industry to find sustainable and cost-effective ingredients in fish diets. Salmon alone requires more than 1.500.000 tons of aqua feeds per year. Plant ingredients are now mainly used to improve sustainability of ingredients used in feeds for high valuable carnivorous species like salmonids. However, plant ingredients have some restrictions, including competitive demand with human consumption and international market availability with escalating prices and questionable sustainability with respect to environmental stewardship, facts that forces the industry to move in other innovative solutions.

In terms of sustainable feed formulations, recent advances prove, among other low trophic level organisms the concept of the nutritional (Kousoulaki et al., 2020) and technical (Samuelsen et al., 2018) feasibility of substituting fish oil by heterotrophically produced microalgae in salmon feeds. Such organisms may be grown on side stream biomass of other agricultural industrial practices. Nevertheless, achieving the desirable circular economy, which demands recycling of organic and inorganic nutrients, we unavoidably press the current set regulatory limits for undesirable compounds in raw materials and seafood products with potential risks for animal health, welfare, production performance and product safety for the consumers.

For the Atlantic salmon nutritional trials, FutureEUAqua compared dietary fishmeal and fish oil with main raw materials that are already or can be produced in high quantities in the future. Those were tunicate meal, insect meal, and phototrophic and heterotrophic microalgae meals, and in the created formulations replaced parts of fishmeal and/or fish oil, and soy-based ingredients, whereas a fishmeal, fish oil and soy-free diet was also formulated combing all the innovative ingredients at once. The preliminary results from these trials showed that growth rates were similar among treatments including innovative ingredients such as tunicates, insect meal and heterotrophic or phototrophic microalgae with reduced fish performance when both fishmeal and fish oil were removed completely from the formulation.

Following the same increasing trend, marine aquaculture industry in Mediterranean has undergone a significant growth producing traditional finfish species like, European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata). Being a rapidly expanding sector, it places enormous pressure on the aquaculture industry to find sustainable and cost-effective ingredients in fish diets. Currently, few non marine origin ingredients allow substantial replacement of fish meals (FM) and fish oils (FO) in sea bass and sea bream feeds without affecting fish performance. This is due to their inadequate content of essential nutrients, including protein, amino acids and minerals as well as the presence of antinutritional components.

Biotechnology has recently played a significant role on animal feed improvement in the production of innovative sustainable feed ingredients, value-addition to forage used as animal feed through processing, production of feed additives and the manipulation of rumen microbes to improve feed utilization. Algae, Bacterial protein and yeast protein constituted the innovative ingredients used for conventional and organic sea bass and sea bream feeds. These ingredients were selected on the basis of potential near future availability and the condition to have the characteristics to be produced organically in the future. According to their nutritional profiles these ingredients, in combination with commonly used conventional and organic raw materials, were tested in laboratory and production scale trials in commercial type aqua feeds.

Both sea bass and sea bream fed the organic and conventional FutureEUAqua diets showed better growth performance when the new ingredients mixture (bacterial protein, yeast meal, fish meal trimmings) inclusion in the diets was at 25% level showing the potential of using such innovations.

Acknowledgements
FutureEUAqua is funded by the H2020 program Sustainable European aquaculture 4.0: nutrition and breeding (GA nr. 817737).

References

1. Eurostat, 2019. https://ec.europa.eu/eurostat/web/products-eurostat-news/-/EDN-20191015-2
2. Kousoulaki,, Berge, G.M., Mørkøre, T., Krasnov, A., Baeverfjord, G., Ytrestøyl, T., Carlehög, M., Sweetman, John, Ruyter, B., 2020. Microalgal Schizochytrium limacinum Biomass Improves Growth and Filet Quality When Used Long-Term as a Replacement for Fish Oil, in Modern Salmon Diets. Front. Mar. Sci., 14 February 2020; https://doi.org/10.3389/fmars.2020.00057
3. Kousoulaki, K., Mørkøre, T. Nengas, I. Berge R. K. and Sweetman J. (2016): Microalgae and organic minerals affect lipid retention efficiency and fillet quality in Atlantic salmon (Salmo salar L.). Aquaculture 451, pp. 47-57.
4. Lembo, P and Mente, E. (2019). Organic aquaculture impacts and future developments. Springer -Nature Publishers. ISBN 978-3-030-05602-5
5. Mente, E. Jokumsen, A., Carter, C., Tacon A., Antonopoulou, E. (2019). Nutrition in relation to organic aquaculture: sources and strategies. Chapter 9 in: Organic aquaculture impacts and future developments (Lembo, P and Mente, E. (Editors), Springer-Nature Publishers.
6. Samuelsen, T.A., Oterhals, Å., Kousoulaki (2018): High lipid microalgae (Schizochytrium sp.) inclusion as a sustainable source of n-3 long-chain PUFA in fish feed—Effects on the extrusion process and physical pellet quality. Animal Feed Science and Technology 236, 14–28.
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About Elena Mente
Professor Elena Mente has more than 20 years’ experience on research in sustainable aquaculture and aquatic animal nutrition. Her research contributes to increasing available, accessible, affordable and nutritious aquafood and feed, while conserving natural resources and contributing to climate change mitigation (FutureEUAqua project). On-going research is related to organic aquaculture and the investigation of how diet affects and to what extent the gut microbial communities and the subsequent food assimilation in aquaculture.

About Katerina Kousoulaki
Dr. Katerina Kousoulaki is senior researcher at Nofima (2007-today). Her research areas are downstream processing, food and feed development, and physiology, i.e., appetite regulation, metabolism, and mineralization, with special interest in novel ingredient applications. In FutureEUAqua she leads tasks related to raw material quality and salmon nutrition. She is the coordinator of AQUABIOPRO-FIT (BBI JU Horizon 2020) developing nutritional supplements for humans from fish side stream biomass.

About Ioannis Nengas
Dr. Ioannis Nengas holds a PhD in Fish Nutrition and he is working at the Hellenic Center for Marine Research on applied fish nutrition. Among his research experiences are the evaluation of nutritional quality of feed ingredients and feeds, nutritional requirements of aquaculture species, formulations of commercial diets, effect of nutrition on quality, health and defense system of fish and fish feed technology. Has participated in numerous European Union and national research projects and produced over 50 publications in peer- reviewed journals.