New solutions to support sustainable growth in aquaculture

EM3 19 AQ new aquafeed Abb. 1Omega-3 fatty acids from microalgae instead of fish oil

Fish oil is not available in sufficient quantities to meet the growing needs of the aquaculture and nutraceutical industries. Although essential omega-3 fatty acids are also to be found in microalgae, production capacity has so far been low. That is now changing, however, and developments in this field are making rapid progress. The first feeds for aquaculture with omega-3 fatty acids from algae are now available on the market.

Human beings – like fish – have to consume a certain amount of essential, long-chain, polyunsaturated fatty acids with their food every day in order to stay healthy and develop "normally". The omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are particularly important. These are not produced in the body but must be obtained from food. Hundreds of scientific studies have revealed that EPA and DHA are of huge importance for the development and health of the brain, eyes and cardiovascular system.

With regard to their use in animal and aquaculture feed both of these fatty acids have up to now been obtained almost exclusively from marine fish oil sources. However, fish oil supply is limited because the available wild fish catches cannot be increased at will and they are also used more for direct human consumption. Global fish oil production is currently stagnant at around one million tonnes a year and is indeed tending to decline. This situation is already endangering the growth of aquaculture which uses almost three-quarters of worldwide fish oil production. Significant increases are not to be expected for the time being despite the fact that fish oil producers now also gain raw materials from previously unused reserves such as slaughterhouse waste and by-catches from the fishing sector which were previously discarded at sea immediately after the catch. It is estimated that 15 to 20 million tonnes more raw material could be taken from these sources each year. Hopes now also rest on the stocks of mesopelagic fish species which live in the oceans at depths of between 200 and 1,000 metres. Scientists have estimated their biomass at 10,000 million tonnes. If this is correct it would be by far the largest known fish resource. Access to these fish, however (they live at the upper limit of the deep sea) poses enormous risks to oceanic ecosystems because we still know far too little about the mesopelagic fish world to be able to use it sustainably.

 

In spite of this, aquafeed producers are increasingly optimistic about their ability to meet aquaculture’s growing feed requirements. And this confidence is justified: progress made in the large-scale use of microalgae has provided a rewarding and virtually inexhaustible source of the much needed omega-3 fatty acids. Basically, the idea of extracting fatty acids directly from microalgae is not new because the microscopically small algae that float in the light-flooded, near-surface layers of the oceans are themselves the producers – i.e. the original source – of omega-3 fatty acids. In the course of the marine food chains the fatty acids accumulate successively in zooplankton and then, further on, in the fish. This means that anyone who wants to make use of the valuable fatty acids does not necessarily have to obtain them from fishes because they are also present in algae biomass. The extraction of fatty acids from algae was for a long time only possible in the lab for there were still no suitable technologies and processes available for the large-scale production of algae. Added to that was the fact that the upscaling of algae production and the extraction of fatty acids from algae required considerable investments. As long as relatively cheap fish oil from fishing sources was available in sufficient quantities it made no sense to look elsewhere. But things look quite different now. In the face of decreasing supply of fish oil the growing demand for omega-3 fatty acids has clearly strengthened the position of algae oil in the competitive field. And because limited supply already leads to rising prices algae cultures have suddenly become economically viable. From an ecological point of view they have always had an advantage anyway, because this method of fatty acid production does completely without fish. In other words it preserves fish stocks.

Schizochytrium algae produce DHA from sugar cane residues

So what is the situation now? The US company TerraVia, which develops technologies for food, nutrition and special ingredients, has pushed forward microalgae culture and extraction processes for fatty acids so that they are now ready to go into practice on a large scale. To commercialise the innovative technology TerraVia has set up a joint venture with the agribusiness company Bunge Limited, one of whose work areas is the processing of oil and cereal seeds. This collaboration will make it possible to achieve a relevant production size more quickly.

In the Brazilian state of São Paulo the joint venture operates a production plant for marine microalgae of the genus Schizochytrium. These are cultivated in huge, six-storey high fermentation tanks. The unicellular marine algae produce particularly large amounts of DHA. Their natural habitat is the mangrove forests of tropical coasts. One energy-saving advantage of this algae species is that it requires no light because it feeds on organic substances such as dead mangrove leaves. This feature can be put to good use in their culture: within the biofermenter the Schizochytrium algae are "fed" on residues of sugar production from sustainably produced sugar cane. These residues come from a neighbouring sugar factory that is certified by Bonsucro according to sustainability criteria. The energy-rich food pulp seems to be much liked by the microalgae which are kept under optimal conditions in the biofermenter: It takes only a few days for their biomass to multiply with the result that a certain proportion can be removed regularly. Dried and processed accordingly, this is then used to produce an omega-3-rich powder which is marketed under the name AlgaPrime DHA and used as an additive for animal feed, particularly in aquaculture. No genetic engineering tricks are needed to produce this algae-based fatty acid for it grows in a completely natural way. The process can be carried out in almost any location that can supply suitable organic substrates for feeding the algae… independent of climatic conditions and other external influences, which enables a stable supply of DHA of constant quality.

TerraVia says that AlgaPrime contains 280mg DHA per gram of dry algae mass. If one translates this to the omega-3 fatty acid content of fish then one tonne of AlgaPrime corresponds to nearly forty tons of industrial fish! This comparison makes it clear why algae cultures are a real omega-3 fatty acid alternative that can reduce our dependence on fish oil and natural resources. AlgaPrime is produced in a sustainable way, it preserves fish stocks, does no damage to the environment, and contains no harmful substances or heavy metals. Another advantage is that AlgaPrime in powder form can be dosed precisely to the gram and added to animal feed as required. The feed producer BioMar already uses AlgaPrime DHA in some of its products that are used in aquaculture in Norway, Scotland and Chile. Omega-3-rich oil from the microalgae Schizochytrium can now even be used in food. The EU Commission approved its placing on the market in accordance with Regulation (EC) No. 258/97 with an implementing decision of the European Parliament and the Council on 14 July 2014.

EM3 19 AQ new aquafeed Abb. 4Evonik and DSM invest USD 200 million in an algae project

The supply situation of omega-3 fatty acids is likely to ease further in the near future. In March 2017, Evonik, a leading specialty chemicals company, and Royal DSM, a science-based health, food and materials company, announced their plan to jointly invest approximately $200 million in a facility for the industrial production of omega-3 fatty acids from natural marine algae.

The joint venture, called Veramaris, has its headquarters in the Netherlands but the production facility will be built at Blair (Nebraska) in the United States, in the immediate vicinity of an existing Evonik plant. This provides direct access to the raw materials that are needed for the production of the high-quality, pure omega-3 fatty acids EPA and DHA. Completion and commissioning of the production facility are scheduled for 2019. Production will initially focus on feeds for salmon aquaculture and pet food. Once the planned production capacity is reached, Veramaris is expected to meet 15 per cent of the annual EPA and DHA needs of the global salmon farming industry. Since the marine algae are produced on land under controlled conditions, salmonid aquaculture now has a sustainable omega-3 source that can be scaled to meet growing demand.

The decision in favour of the 200 million dollar investment, which is shared equally by Evonik and DSM, was preceded by various feasibility studies and tests... not only to examine the demand for omega-3 fatty acids and highly concentrated algae oil products for animal nutrition, but also to test other parameters that are decisive for the cost-effectiveness of production. At an existing DSM plant in Kingstree, South Carolina, USA, the two companies produced omega-3 algae oil in advance in a pilot plant so that the product could be thoroughly tested in practice. In collaboration with feed manufacturer Skretting, for example, the digestibility and absorption of algae oil in the fish body and its influence on the growth and health of salmon and trout were investigated. The results were apparently so convincing that the decision was taken to build the large-scale plant. This positive step was probably also influenced by EU approval which gave the go-ahead for the use of algae oil in animal feed.

The highly concentrated algae oil "MicroBalance" consists of more than 50% DHA and EPA and is free of any impurities. According to Evonik and DSM, 1 kg of their EPA- and DHA-rich algae oil replaces approximately 60 kg of wild fish. Both emphasize that process and product development was only possible due to the complementary competencies that Evonik and DSM brought to the cooperation. DSM is a recognized specialist in biotechnology, the culture of algae and other aquatic organisms. The science-based company has particular expertise in life sciences, health, nutrition and materials sciences. Evonik, a creative industrial group from Germany, is one of the world's leading suppliers of specialty chemicals and currently concentrates its activities on the megatrends health, nutrition, resource efficiency and globalization.

"Fish-free” feeds can safeguard the future of aquaculture

In February 2017 two US companies, Heliae and Syndel, announced a partnership for the mass production and distribution of Nymega, a new algae-based DHA-containing component for aquaculture feeds. From its headquarters in Ferndale, Washington, Syndel manufactures and markets a wide range of products specifically designed for fish health and biosafety for the global aquaculture industry. Heliae, an applied life sciences and technology company located on the outskirts of Phoenix, Arizona, focuses on the research and development of algae and other lower organisms. In the announcement of the strategic cooperation it was pointed out that the algae required for Nymega can be produced cheaply. Nymega's DHA content can be targeted at specific fish species and stages of development which offers particular advantages during use and enables affordable prices.

The possibility of industrial production of omega-3-rich algae-based products for aquaculture is a long-awaited step and innovation breakthrough in that it makes the vision of salmon farming without fish-based resources a little more realistic. The use of fish meal and fish oil in aquaculture feed is becoming increasingly untenable both ecologically and economically. Their replacement by algae-based EPA and DHA alternatives improves the fish-in-fish-out balance of salmon farming and enables aquaculture to continue to grow sustainably. Most experts will agree that the future of aquaculture lies in "fish-free" feed and that algae will play a central role here. This opens up a broad field of activity for science since the characteristics and potentials of this diverse group of organisms have only just been recognised and require further thorough investigation. It will be worth it: the global aquafeed market was already estimated at more than USD 100 billion in 2017 and continues to grow at annual growth rates of almost 12 per cent!

EM3 19 AQ new aquafeed Abb. 5Algae are not a substitute but an equivalent alternative

The biochemical diversity displayed by algae is much greater than that seen in land plants, something which paleobiologists see as an indication of the early evolutionary divergence of algae groups in the history of life on earth. Although macro- and microalgae are generally regarded as "plants" they are very different from land plants. This is also reflected in the composition of their components. Some algae species may even be suitable as an alternative to fish meal in fish feeds because they contain a high proportion of high-quality proteins and all essential amino acids. Their value for fish nutrition is estimated to be about as high as that of fish meal. In addition, some macroalgae such as Laminaria, Undaria and Porphyra as well as certain microalgae also contain significant concentrations of taurine. This organic acid, with which many people are familiar only as a component of energy drinks, is considered an essential nutrient for carnivorous animals, including fish. Although taurine is not an amino acid in the strictly scientific sense it is usually classified as such. The importance of this substance, which in contrast to algae does not occur in land plants, lies in its ability to maintain organ and cell functions. Taurine stabilizes the fluid balance in cells, has an antioxidant effect and increases the regularity and strength of heart contractions.

Other algae such as Haematococcus, Spirulina or Dunaliella can serve as pigment sources in fish feed for they contain considerable amounts of precursors of astaxanthin and carotenoids. This makes them ideal for applications in salmon and trout farming as well as in the hobby sector because they intensify the colouring of koi carp and other ornamental fish. A lot of algae species already play an important role in aquaculture. It is well known that the addition of microalgae to the rearing tanks of fish larvae ("green water") has a number of advantages. For example, they prevent larvae from colliding with the walls of the tank, they improve the absorption of live food (zooplankton) because the prey organisms can be fixed more precisely, they increase the nutritional value of the prey and strengthen the digestive function of the larvae and their immune system. There are now dried algae in pasty or pill form, which makes them more practical for use. However, the nutritional and physical properties of such preparations often require adjustments. That is why many hatcheries continue to produce their own requirements of high-quality microalgae in their own cultivation systems. This is expensive and time-consuming but fully justified by the exceptional nutritional value of the algae. 

Before algae can be used to feed fish they sometimes have to be specially prepared first. Some algae species, for example, produce extracellular polysaccharides that act as binding agents in the feed pellets but at the same time make the absorption of nutrients more difficult. Thick cell walls, such as those found in Chlorella algae, have a similar effect. Some types of algae also contain substances and trace elements that can be indigestible or even harmful. If it is not possible to successfully eliminate these inhibitors (Latin: hinder, prevent) the algae in question may be unsuitable for use in fish feed, despite an excellent nutrient spectrum. Inhibitors can be found in some kelp species that contain phenolic resins and in Laurencia red algae that contain harmful brominated compounds.

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