Seaweed – an untapped source of protein and bioactive compounds for aquaculture

Seaweed – an untapped source of protein and bioactive compounds for aquaculture

Seaweed is fast gaining a reputation as the ideal sustainable food source. Certainly, the nutritional properties of seaweeds are both unique and interesting, with some seaweeds having protein levels as high as 47%. Seaweed, therefore, represents an untapped source of protein and has great future potential.

As the global population continues to rise, the need for sustainable, alternative sources of protein also increases. In fact, it is estimated that the worldwide requirement for food will increase up to 50% by 2030, thus highlighting the absolute need for sustainable development. Recently, Ocean Harvest Technology has worked in collaboration with a number of research institutes to evaluate the use of different seaweeds as a sustainable protein source for aquaculture.

Why Seaweed Protein?

Protein is the most expensive constituent of fish feed whereby global expenditure exceeds €1bn per annum. Fishmeal is a high-protein animal feed used extensively in aquaculture but uses wild fish stocks to feed farmed fish and is an unsustainable feed resource. The ability of fishmeal supply to meet future demand is a massive global concern – especially given that aquaculture production is growing at a rate of nearly 9% per annum.

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Ocean Harvest Technology Produce

As wild fish stocks decline, the aquaculture industry faces a massive challenge to identify cost-effective and environmentally-friendly alternatives to fishmeal on which it is so heavily reliant. Seaweed protein has the potential to provide a solution to this problem as it is relatively underexploited, contains high amounts of protein and can be cultured in a sustainable, environmentally-friendly manner.

Essential Nutrients

Proteins are an important source of energy, present in all cells and are an essential component of most biochemical processes. Proteins comprise one or more chains of various amino acids, organised in a specific manner that give the protein a specific structure. When ingested, proteins are broken down into amino acids or short chains of amino acids called peptides. These amino acids play key roles in important metabolic pathways associated with maintenance, growth, reproduction, and immunity.

Amino acids can be classified as either essential or non-essential. Essential amino acids cannot be produced by the animal and must be sourced solely from the diet. Most seaweed species contain all of the essential amino acids and are also rich in some nonessential amino acids such as aspartic and glutamic acid.

In general, the protein content of seaweed ranges from 3-47% and considerable differences exist in the protein content of brown, green and red seaweeds. In contrast to brown seaweeds, red seaweeds contain higher levels of protein which can be up to 47% (Porphyra sp.). Brown seaweeds can have protein levels up to around 20% (Alaria esculenta) whereas the levels found in green seaweeds are as high as 29% (Ulva lactuca). Differences in season, species and environment can have a significant impact on the composition of amino acids and protein in seaweeds.

Bioactive Proteins

Seaweed is a natural source of biologically active proteins, amino acids and peptides. Two groups of bioactive proteins – lectins and phycobiliproteins – are present in some seaweed. Lectins are a group of carbohydrate-binding proteins that display anti-bacterial, anti-cancer, anti-HIV and anti-inflammatory biological activity; lectins have been successfully isolated from a number of seaweeds including Eucheuma sp. and Codium fragile.

Harvesting Seaweed to extract protein

Harvesting Seaweed to extract protein

Another group of proteins – phycobiliproteins – exhibit antioxidant, anti-inflammatory, cholesterol-lowering and antiviral activities to name but a few and have been isolated from the red seaweed, Palmaria palmata. A number of bioactive amino acids are also present in seaweed. One such example is taurine – a bioactive amino acid required for some biological functions. Other bioactive amino acids present in seaweeds include laminine, kainoids, and mycosporinelike amino acids. These amino acids have a wide range of biological properties including antioxidant, hypotensive, insecticidal, anthelmintic, and neuroexcitatory activity. In addition to bioactive amino acids, some bioactive peptides have been isolated from seaweed. These include carnosine and glutathione both of which are antioxidant peptides that protect cells from damage caused by reactive oxygen species. Another bioactive peptide produced by seaweed is Kahalalide F which is a cyclic depsipeptide with anti-cancer activity and is also active in the treatment of AIDS.

Seaweed Protein in Aquafeed

The functional biological properties of seaweed protein make it an excellent candidate for a natural, sustainable alternative to fishmeal in aquaculture. The capacity for large-scale production of seaweeds in Ireland, together with the high-purity seaweed protein extraction developed by Ocean Harvest Technology further enhances the future potential. The availability of such sustainable protein sources is a prerequisite for our ability to continually produce high-quality and safe products.

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Seaweed Protein: Properties and Possibilities in Aquaculture

Seaweed Protein: Properties and Possibilities in Aquaculture

Seaweed is a natural and sustainable ingredient with a lot of different functional biological properties, amongst them protein. Protein are biochemical compounds comprising one or more polypeptides typically folded into a globular or fibrous form that facilitate biological functions in the body.

Although the structure and biological properties of seaweed proteins are still poorly documented, the amino acid compositions of several species have been known for a long time. Habitat – and especially seasonal variation – has an effect on proteins, peptides and amino acids in seaweed. The protein fraction of seaweed varies with the species but is generally low in brown seaweed, <15%. Higher protein contents are recorded for green and red seaweed, up to 40%. These levels are comparable to those found in highprotein vegetables such as soybeans.

Essential Amino Acids

Most seaweed species contain all the essential amino acids and are a rich source of the acidic amino acids, aspartic acid and glutamic acid and in general are higher than those found in terrestrial plants.

One bioactive protein present in algae are lectins, which are a structurally diverse group of carbohydrate binding proteins. Marine algal lectins exhibit antibiotic, mitogenic, cytotoxic, anti-nociceptive, anti-inflammatory, antiadhesion and anti-HIV bioactive properties and are currently commercially produced for a variety of purposes.

Peptides are 2-20 amino acid long chains which once a protein is broken down are released and become bioactive and fulfil certain functions in the body. The depsi-peptide kahalalide-F from Bryopsis sp. – a green alga is active in the treatment of lung cancer, tumours and AIDS. Many other bioactive functions have been ascribed to algal peptides. When protein and peptides are broken down to their individual building blocks we have amino acids. The eight essential amino acids (cystine, isoleucine, leucine, lysine, methionine, phenylalanine, tyrosine and valine) cannot be synthesised by animals, nor can they be replaced by other ‘less valuable building blocks.

All essential amino acids are present in brown and red seaweed species; red species feature uniquely high concentrations of taurine – an ingredient found in a well-known energy drink.

Extracting Protein

Ocean Harvest Technology in association with several universities has already embarked on optimising extracting total protein – finding and isolating bioactive peptides for applications in aquaculture and animal feed.

Harvesting Seaweed to extract protein

Harvesting Seaweed to extract protein

Why is this important?

Because a global protein crisis is looming. Currently, about 5 million tonnes of fishmeal is produced and used as feed ingredient in livestock and aquaculture. Virtually all fishmeal is used as a high protein ingredient in feed for farmed land animals and farmed fish. The typical inclusion rate for fishmeal in farm animal diets is 1-5% of dry matter, mainly in specialist diets – e.g. for weaner pigs. A typical farmed salmon diet contains 20-30% fishmeal.

Fishmeal Components

In the ten years to 2002, aquaculture expanded worldwide by more than 9% per annum and since then at a slightly slower rate. While the use of fishmeal will consequently increase – improved efficiency and some substitution means this is likely to be at a slower rate.

Making Pellets from Seaweed Protein

Making Pellets from Seaweed Protein

Nevertheless, fish stocks used for fishmeal are diminishing and prices are rising. A lot of work has taken place on plant protein as replacement; however, often these plant proteins like soya are less suitable for use in aquaculture due to anti-nutritional factors or lower performance. The large fish-feed manufacturers currently purchase more than €1bn in fish protein and oil per year, sourced primarily from South America by harvesting wild fish from around the world.

Two of the biggest financial and environmental costs for these companies and all fish-feed processors are increasing shortage and the spiralling cost of fish protein. It takes 3-4 kg of wild fish (herring, capelin for example) to create 1kg of fish meal. This is a completely unsustainable scenario that has a major negative impact on the ocean environment.

Seaweed Purity

Seaweed protein extracted for example by Ocean Harvest Technology has a high purity, comprising over 80% protein in contrast to fishmeal at about 65%. It is also extremely popular amongst aquaculture feed manufacturers because of its excellent amino acid profile.

When large-scale production of seaweeds starts in earnest (e.g. in Ireland), it most definitely could help alleviate the problem currently experienced with fish meal and plant protein  replacements. Moreover, seaweed protein is derived from a sustainable marine resource and does not have the stigma of being a food crop.

These attributes make seaweed protein an excellent source for use in aquaculture feeds and show great potential for it in the future.

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Tide must turn to use potential of seaweed

An estimated 100,000 ton of seaweed washes up daily on the Irish coastline, but only a fraction of this resource is currently being exploited for its potential as a foodstuff, and the raw material for medical, cosmetic and other uses.

Countries such as Norway, France and Spain are decades ahead of us when it comes to the commercial harvesting of seaweed, and IFA aquaculture secretary Richie Flynn believes exploiting our seaweed resources needs to be part of any government vision for the overall seafood industry.

“There is huge potential for public-private investment on the seaweed side,” says Mr Flynn.

“Apart from the food industry, the research proves there’s a multitude of potential uses for seaweed in the medical and synthetics In the ocean, some seaweed stands proudly up from the Ocean floorindustries.

“It’s a really exciting area for new development, if only the relevant government authorities would allow our SMEs [small and medium enterprises] to fully research and develop the scope of the product that is out there.

“This is a sustainable and renewable resource, and 100,000t of it washes up on our shores every day.

“It’s a no-brainer that developing this resource should be a priority for the so-called ‘smart economy’.”

One company that is taking a lead in the hi-tech application of Ireland’s seaweed resources is Ocean Harvest Technology, based in Tuam.

After seven years of research, Ocean Harvest is ready to start commercial production of a new salmon-feed ingredient, which some experts believe could help revolutionise the €6bn global salmon-farming industry.

It’s an industry that has been dogged by environmental, animal welfare and food safety concerns, but some of these issues could be addressed by Ocean Harvest’s organic OceanFeed salmon-feed ingredient, which is made from a mix of seaweeds — 40pc of which is sourced in Irish waters.

OceanFeed replaces the synthetic chemical additives and colourants currently used in salmon fish feed and has been shown to improve the health of the environment in which the fish are reared.

Test results have also confirmed that fish eating OceanFeed have increased resistance to sea-lice infestation, one of the big environmental problems in salmon farming.

“As an industry, salmon farming has taken significant criticism in terms of environmental impact,” says Patrick Martin, an Irish seafood expert, who co-founded Ocean Harvest along with Dr Stefan Kraan, an internationally recognised authority on seaweed and former head of the Irish Seaweed Centre at NUI Galway.

“The long-term importance and value of aquaculture means that sustainable solutions have to be found and we believe OceanFeed will be a key ingredient in making the industry more environmentally as well as financially sustainable.”

EWOS, one of the main suppliers of feed for the global salmon farming industry, assisted Ocean Harvest on the technical side of manufacturing its OceanFeed product, and Dr Kraan says the industry response has been very positive. “It’s a slow process, but there are contracts in place, and the big retail players [such as] Tesco and Sainsbury’s are interested,” he said.

The Ocean Harvest Technology LogoOcean Harvest’s salmon feed ingredient was developed after several years of research into the commercial application of seaweed.

Dr Kraan believes it’s just one example of the type of product that could be developed from the seaweed species in Irish waters.

“We could build a whole industry around seaweed,” he said.

“The Norwegians have been at it for the last 50 years. Harvesting seaweed is like cutting your lawn — it always grows back. Apart from the food industry, there are many other applications in the medical, alginates and cosmetics areas, and seaweed could also be a key ingredient in the production of bioethanol.

“There are 625 species of seaweed around the Irish coastline, so Ireland should be heaven on Earth for seaweed researchers and entrepreneurs.”

– Ronnie Belle

Dr Krann inspecting seaweed

Salmon Feed Breakthrough for Ocean Harvest Technology

Salmon Feed Breakthrough for Ocean Harvest Technology

Ocean Harvest Technology, based in Galway on the Atlantic coast of Ireland is about to start commercial production of a new salmon feed ingredient that could revolutionise the €6 Billion global salmon farming industry.

The Ocean Harvest Technology Logo

The industry has been beset by concerns over environmental impact, animal welfare and food safety concerns but all of those issues will be addressed by OceanFeed™, a wholly sustainable, seaweed-based salmon feed ingredient that not only replaces all synthetic chemical additives and colorants currently used in salmon fish feed – but also has been shown to significantly improve the health environment in which the fish are reared.

OceanFeed™ is a macro algae-based ingredient which is 100 per cent natural and wholly sustainable within the ocean environment.

Recently completed European sea trials with EWOS in Scotland have shown that the thousands of fish used in the trial have been healthier and displayed better weight gain, taste and appearance results when compared to fish fed on the current market leading feed.

Astaxanthin levels in fish fed on the OceanFeed diet were only 20 per cent of those in the control diet fed fish while OceanFeed™contained higher levels of natural pigments, notably Lutein, and of Omega 3 PUFA’s.

The feed ingredients are designed to reduce stress, enhance the immune system and minimize autoimmune problems, At the same time, the fish eating OceanFeed™ have significantly improved flesh quality and flavour — the ‘taste of the sea’ compared to a control test group.

The feed reduces many of the environmental issues associated with current aquaculture practices. Many of these have related to the use of synthetic, petroleum-based additives that represent about 20 per cent of the cost and 15 per cent of the weight of farmed salmon fish feed.

The market for additives used in the manufacture of salmon feed was worth more than US$615 million in 2007.

OceanFeed™ is the first commercial product to emerge from several years’ worth of research and development into the application of macro-algae and seaweed based products conducted by the team at Ocean Harvest Technology.

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When pigs will swim?

When pigs will swim?

The world population is ever increasing and so is pork consumption . During the last 40 years, global pork production increased with a factor 4 from 24.7 million ton in 1961 to 100.6 million ton in 2009 (FAO, 2011). However, as usual the case with intensive farming many disease-associated problems start to develop, resulting into increased chemical and antibiotic use in the industry. Bioactives in seaweeds might be one of the answers to make the industry more sustainable and chemical free, making pigs more of a marine mammal!

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Link to OceanFeed Swine product information

 Disease and antibiotic use

Intensive pig farming is susceptible to many diseases amongst them several bacterial diseases and parasitic worms. In human medicine, antibiotic use is generally confined to treatment of illness. In contrast, antibiotics and other antimicrobials often are routinely given to food animals in order to grow animals faster and to compensate for unsanitary conditions on many industrial farms. Bacteria exposed to antibiotics at low doses for prolonged periods can develop antibiotic-resistance—a dangerous trait enabling bacteria to survive and grow instead of being inhibited or destroyed by therapeutic doses of a drug. Since many of the classes of antibiotics used in food animal production also are important in human medicine, resistance that begins on the farm can lead to a serious public health problem.  This has already happened in the border area between The Netherlands and Germany where pigs with a type of MRSA have developed 100% resistance to tetracyclines (an antibiotic) and has jumped from pigs to humans with the resulting consequences that there is no antibiotic treatment available. The same has happened in Britain with Clostridium difficile.

Recognizing the potential for a health crisis, Denmark stopped the administration of antibiotics used for growth promotion (i.e., non-medical uses). Today in Denmark, all uses of antibiotics in food animals must be accompanied by a prescription in a valid veterinarian-client-patient relationship, and veterinarians cannot profit from the sale of antibiotics. In addition, farmers, veterinarians and pharmacies must report the use and sale of antibiotics, and farm inspections are conducted regularly. The Danish government and industry data show that livestock and poultry production has increased since the ban, while antibiotic resistance has declined on farms and in meat. There are real concerns that unless antibiotics are used much more sparingly we will soon find ourselves facing a range of serious diseases in humans and animals that can no longer be treated effectively.

 Natural alternatives

With several countries now banning or voluntary reducing the antibiotic use an urgent need has arisen to use alternative and sustainable feed ingredients and antibiotic replacements. The recent food scares in the swine industry in 2008 (Ireland) and 2011 (Germany) showing pork with unacceptable high levels of PCB’s and dioxins and other bio-accumulative contaminants, demanded further action to be taken to reduce contaminant levels in feed. Moreover, there has been a strongly growing demand for organic farmed products in many countries, insisting that pigs have to be organically fed and reared. In this respect seaweeds have received limited attention; nevertheless several studies have demonstrated that seaweeds can be used as partial replacement for many ingredients in animal feeds, such as, vitamin & mineral mixes, binders, antibiotics, and antioxidants. Several studies have shown that addition of single seaweed species can reduce certain enterobacteria, improve pig gut health and increase iodine in meat. Furthermore they have an antibacterial effect and prebiotic effect and help reducing scouring/ Diarrhoea and Ammonia reduction.

Certain bioactive molecules from seaweed like laminarin and fucoidan have a pronounced anti-microbial action, similar to in-feed antibiotics in piglets. This is beneficial from a performance perspective, as a lower microbial load will result in a lower energy cost to the pig. Also, the removal of harmful bacteria like E. coli helps control disease rates in piglets.

 Ocean Harvest Technology

The Ocean Harvest Technology LogoTo tackle current problems Ocean Harvest Technology has developed and specific macroalgae mix for the swine industry. Oceanfeed™- swine contains a plethora of natural bioactive compounds which by incorporating in the diet can modulate several functions in the pig and assist in the control of chronic diseases and infections found in the pig industry. It allows for disease-free farmed pigs to be reared in a more natural and sustainable way, easing concerns on environmental impact and sustainability. Oceanfeed™-swine is the first marine natural and sustainable functional feed ingredient derived from macroalgae. Nutrition plays a key role in the efficient production of pork, and accounts for more than 70% of the cost of production. Nutrition is constantly evolving in order to ensure we cost effectively supply the feeds to produce high quality pork.

Earlier this year Ocean Harvest Technology in conjunction with Sharragh pigfarms conducted feeding trials with 240 pigs and Oceanfeed-swine at different percentages of inclusion (0.5%, 2% and 5%) and compared the results against an industry reference diet. During and at the end of the trial 16 pigs were slaughtered and processed at the Dawn Pork and Bacon factory in Waterford. Intestinal samples were taken and meat samples were obtained after the pigs were processed by a local butcher (Jarlath Kelly, Tuam) and send to University College Cork for taste analysis and packaging trials. After 4 months of trial from weaning stage to 100 kg pigs the results showed a positive outcome in several ways.

The following results have been obtained:

  1. Higher weight gain, leaner meat and lower food conversion efficiency when pigs were supplemented with 0.5% Oceanfeed-Swine
  1. Significantly improved flavor, juiciness and overall consumer acceptability of the meat at 5% inclusion of Oceanfeed-Swine
  2. Improved observed health and alertness of animals at trial site

There are still some results to be analyzed on gut flora and gut development but the results so far are very encouraging for full commercialization of Oceanfeed-Swine. This strongly indicates that seaweeds could play an important role in intensive swine farming in Ireland and the EU.

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Seaweed and the aquaculture Industry; feed it or grow it!

Seaweed and the aquaculture Industry; feed it or grow it!

Anecdotal observations over many years have suggested that seaweeds are an important nutritional resource for terrestrial and aquatic species. Sheep are known to graze regularly on seaweed if they have coastal access. Cod have been observed grazing on seaweed immediately before breeding, while single species of seaweed have demonstrated a significant improvement in disease resistance when included in diets for farmed shrimp. Over the last 10 years the fed aquaculture industry has been bombarded by concerns over environmental impact, animal welfare, sustainability and food safety concerns.

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Ocean Harvest Technology Produce

Seaweeds have been used historically as a feed supplement, but only as single species of seaweed. Benefits from use of seaweed as feed supplements are well documented in many research publications. Different species of seaweed contain many different bioactive molecules. These bioactive ingredients are:

  • Lectins, phycobiliproteins, peptides and functional amino acids such as laminine and hydroxyproline
  • Fucoidan, laminarin, alginic acid, mannitol, carageenan, agars and other short chain oligosaccharides
  • Antioxidants, phenolic compounds and pigments
  • Sterols
  • Fatty Acids
  • Iodine
  • Bromophenols

Scientific evidence of the last decade has shown that these ingredients have antibiotic, antiviral, antimicrobial, mitogenic, anti-inflammatory, anti-adhesion, ACE-inhibitory, antioxidant, anti-cancer and antithrombotic effects with immune-modulation and cytomodulatory effects.

In addition to these ‘bioactive’ molecules seaweeds are a rich source of vitamins and minerals and the right blend of seaweeds can replace most or all of the ‘synthetic’ sources of these ingredients that are used in aquatic and animal feeds.

The Ocean Harvest Technology LogoWith this in mind Ocean Harvest Technology Ltd, an Irish company operating out of Milltown, saw an opportunity and formulated and tested a seaweed-based ingredient, OceanfeedTM that addresses the issues of sustainability and the use of ‘chemical’ ingredients that gives significantly improved performance in growth rate, feed conversion ratio, mortalities, disease and lice resistance and finally flavour and texture of Salmon and shrimp. Many of these synthetic additives such as colorants, antibiotics and preservatives end up in the farmed salmon and have led to recent health scares. An urgent need has arisen for cost-effective alternative and sustainable organic and natural fish feed ingredients and Oceanfeed™ can be part of the solution.

Trial results   

Exhaustive trials were run at the Trial Feed Unit owned and operated by Marine Harvest on the Scottish west coast. The feeds, both reference and test, were manufactured by EWOS (UK) Ltd.  The fish were mixed sex Atlantic Salmon smolts with a starting weight of 145 gms and fish were fed to satiation, light regime followed natural photoperiod and water temperature was ambient. All trials were run in triplicate and the cages were inspected daily. All other physical parameters were measured on a daily basis, and mortalities were recorded on a daily basis. Fish were sampled and assessed against standard farming KPI’s (Key Performance Indicators). Evaluation included growth rate, feed conversion ratio (FCR), condition factor, yield, fat analysis, lice counts, pigmentation, lipid content and profile, flesh flavour and flesh texture. Samples of whole guts were taken for microbiological evaluation and samples of lower intestine were taken (being immediately fixed in buffered formalin) for histological examination. Scottish Quality Cuts (SQC’s) of flesh were taken for lipid analysis, lipid profile, protein analysis and pigment analysis.

IMG_0668

The trial was run for over 1.5 years to go through to complete life cycle from smolt up to 5-7 kg salmon. The following benefits were shown at a 15% inclusion levels of oceanfeed compared with a high grade reference diet:

  1. Higher weight gain
  2. FCR lowered by 0.1 point
  3. Uptake of pigmentation from algae up to 23-24 on SalmoFan.
  4. Higher Omega 3 oil levels in feed
  5. Overall health improvement and faster recovery from Anesthetic
  6. Significant lower sea lice on fish, up to 60% less gravid females and adult stages of male and female lice
  7. 55% lower mortality rates
  8. No deformities or runts
  9. Improved gut health as shown in histological staining of gut sections of trial fish. Caused by short chain Oligosaccharides
  10. Significantly improved taste and texture of fish
  11. Low fat (belly flaps) and leaner fish
  12. Easier to process, fillet and smoke (no oil leakage)
  13. Improved environmental record due to no release of foreign synthetic matters in the feed. Seaweed is a marine product harvested from the marine environment in a sustainable way.

Shrimp trials

The shrimp industry is a factor 10+ larger compared to salmon, with salmon needing about 1.8 million tonnes of feed per annum and shrimp 28 million tonnes of feed. With the results from the salmon trial we could with some adjustments do a similar thing and replace premixes in shrimp feed and improve disease resistance. This shrimp seaweed ingredient called Oceanfeed™- shrimp contains a plethora of natural bioactive compounds which by incorporating in the diet can modulate several functions in shrimp and assist in the control of chronic diseases and viral infections found in farmed shrimp. It allows for disease free farmed shrimp to be reared in a more natural and sustainable way, easing concerns on environmental impact and sustainability. Late last year and early this year several shrimp trials were undertaken using a 10% Oceanfeed diet compared to high standard reference shrimp feed in P. monodon and vannemei, globally the two most cultured shrimp. At the end of the trial part of the shrimps were blast frozen and send for taste testing. After the growth trials OHT commissioned the Shrimp Research unit of the University of Ghent to conduct challenge tests to test for the effect of the inclusion of Oceanfeed on viral and bacterial diseases. The results showed a positive outcome of having Oceanfeed incorporated at 10% in the diet.  In brief the following results were obtained:

  • Higher weight gain (Shrimp fed with Oceanfeed at harvest were 5.2% heavier on average than control)
  • FCR lowered by 0.1 point
  • Uptake of pigmentation from algae in Shrimp.
  • 25% lower mortality rates
  • No deformities or runts
  • Significantly improved taste and texture of the shrimp. Tested and proven with independent taste panels
  • Improved survival and onset of mortality times
  • Improved environmental record due to no release of foreign synthetic matters in the feed. Seaweed is a marine product harvested from the marine environment in a sustainable way.

OceanFeed Shrimp

Growing seaweeds

As most seaweeds that we use for Oceanfeed™ are still from sustainable wild harvest we looked at the possibility of cultivating specific seaweeds of high importance for our feed formulations. Of course seaweed cultivation is nothing new and has been practised for over 300 years in Japan. In Asia, seaweed cultivation is by far more important in terms of output and value than any other form of aquaculture. Looking at a global scale the value of cultivated, managed and wild harvested seaweeds exceed over € 7.0 billion with 89% of this value derived from aquaculture. Seaweeds are also the industrial sources of carrageenans (Chondrus, Eucheuma and Kappaphycus), alginates (Ascophyllum, Laminaria, and Macrocystis) and agars (Gelidium  and Gracilaria). These important polysaccharides are used in the food, textile, paint, biotechnological and biomedical industries and have a global value of approximately € 600 million. Seaweeds have significant value in agriculture as soil additives, fertilizers and seaweed meals with their value over € 20 million. The increasing demand for safe, healthy, and minimally processed foods is creating an opportunity for seaweed products as functional foods, nutraceuticals, and alternative medicinal products. In Ireland, over the last 5 years a strong interest has developed in seaweeds as functional food or nutraceuticals. Research is focused on the establishment of low-volume high-value seaweeds in aquaculture. Moreover, new applications of algae and specific algal compounds in different sectors, such as food supplements, cosmetics, biomedicine and biotechnology are developed. Recent trends in life style towards natural, healthy products are favourable for advancement of seaweed aquaculture in Ireland

Additional environmental benefits

Seaweeds are well-able to reduce N and P in their surrounding environment. If no fertilizers are used seaweed farms could act as N and P filtering units in near coastal environments reducing eutrophication risks from agricultural land run-off .Moreover, seaweed farms can act as short-term CO2 sink reducing acidification of global oceans. Inputs of  biodegradable organic matter and inputs deriving from fertiliser run-off together with run off or dilution from finfish and shellfish rearing in near-shore waters and land based activities have many effects on the quality of coastal inshore waters and are a primary cause of eutrophication due to increased availability of nutrients. Kelp farms (inshore and nearshore) are able to act as bio-filters and are able to remove nitrates and phosphates from the surrounding eutrophic inshore waters. This allows for increased production of farmed seaweed as demonstrated by Chopin et al.,in Canada. Eutrophe waters are high in ammonia and phosphorous which can be stripped from the water by seaweed at rates varying from 60% up to 90% of the nutrient input. Macroalgae are able to take up nitrogen from seawater with rates to allow for a biomass increase of ca. 10% day-1. It is well documented that the green alga Ulva is able to remove 90% of the nitrogenous compounds and the red alga Gracilaria up to 95% of dissolved ammonium from fish effluent. By sea cultivating and harvesting macroalgae as biofilters integrated with other shellfish or fish production systems, nutrient polution from these aquaculture systems could be alleviated through a process called IMTA (Integrated Multitrophic Aquaculture) while increasing production and carrying capacity. Production of macroalgae in near-shore sea cultivation can be harvested for the bioethanol market to produce a value added marketable product acting as both an economic incentive and environmental incentive.

However, the focus has shifted and is more and more fixed on alternative protein resources. Seaweed has levels of crude protein between 15-40% of the dryweight and could be an untapped resource for protein production for fed aquaculture. Analysis of the amino acid profiles of the protein fraction shows very comparable or better profiles compared to fish meal, with the advantage that seaweed protein is about 90% of the extracted product while fishmeal contains about 60-70% protein. By using seaweeds and seaweed proteins it will help reduce the pressure and reliance on wild fish stock and some other traditional ingredients and will soon play an important role in the feed and food production. . Development of future large-scale seaweed farms will positively contribute to the growth of maritime sectors and can be a viable alternative for fisherman as existing infrastructure can be applied. It further might enhance employment opportunities in local rural coastal areas in the form of seed hatcheries, seeding units and processing units and create employment opportunities that otherwise would not exist.

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