̽��ֱ�� of Cambridge - David Willer

Fish fed to farmed salmon should be part of our diet, too, study suggests

cg605 — Wed, 20 Mar 2024 16:10:00 +0000

Scientists found that farmed salmon production leads to an overall loss of essential dietary nutrients. They say that eating more wild ‘feed’ species directly could benefit our health while reducing aquaculture demand for finite marine resources.

Researchers analysed the flow of nutrients from the edible species of wild fish used as feed, to the farmed salmon they were fed to. They found a decrease in six out of nine nutrients in the salmon fillet – calcium, iodine, iron, omega-3, vitamin B12 and vitamin A, but increased levels of selenium and zinc.

Most wild ‘feed’ fish met dietary nutrient recommendations at smaller portion sizes than farmed Atlantic salmon, including omega-3 fatty acids which are known to reduce the risk of cardiovascular disease and stroke.

“What we’re seeing is that most species of wild fish used as feed have a similar or greater density and range of micronutrients than farmed salmon fillets,” said lead author, Dr David Willer, Zoology Department, ̽��ֱ�� of Cambridge.

“Whilst still enjoying eating salmon and supporting sustainable growth in the sector, people should consider eating a greater and wider variety of wild fish species like sardines, mackerel and anchovies, to get more essential nutrients straight to their plate.”

In the UK, 71% of adults have insufficient vitamin D in winter, and teenage girls and women often have deficiencies of iodine, selenium and iron. Yet while, 24% of adults ate salmon weekly, only 5.4% ate mackerel, 1% anchovies and just 0.4% herring.

“Making a few small changes to our diet around the type of fish that we eat can go a long way to changing some of these deficiencies and increasing the health of both our population and planet,” said Willer.

̽��ֱ��researchers found consuming one-third of current food-grade wild feed fish directly would be the most efficient way of maximising nutrients from the sea.

“Marine fisheries are important local and global food systems, but large catches are being diverted towards farm feeds. Prioritising nutritious seafood for people can help improve both diets and ocean sustainability,” said senior author Dr James Robinson, Lancaster ̽��ֱ��.

This approach could help address global nutrient deficiencies say the team of scientists from the ̽��ֱ�� of Cambridge, Lancaster ̽��ֱ��, ̽��ֱ�� of Stirling and the ̽��ֱ�� of Aberdeen.

̽��ֱ��study was published today in the journal, Nature Food.

̽��ֱ��scientists calculated the balance of nutrients in edible portions of whole wild fish, used within pelleted salmon feed in Norway, compared to the farmed salmon fillets.

They focused on nine nutrients that are essential in human diets and concentrated in seafood – iodine, calcium, iron, vitamin B12, vitamin A, omega-3 (EPA + DHA), vitamin D, zinc and selenium.

̽��ֱ��wild fish studied included Pacific and Peruvian anchoveta, and Atlantic herring, mackerel, sprat and blue whiting – which are all marketed and consumed as seafood.

They found that these six feed species contained a greater, or similar, concentration of nutrients as the farmed salmon fillets. Quantities of calcium were over five times higher in wild feed fish fillets than salmon fillets, iodine was four times higher, and iron, omega-3, vitamin B12, and vitamin A were over 1.5 times higher.

Wild feed species and salmon had comparable quantities of vitamin D.

Zinc and selenium were found to be higher in salmon than the wild feed species – the researchers say these extra quantities are due to other salmon feed ingredients and are a real mark of progress in the salmon sector.

“Farmed salmon is an excellent source of nutrition, and is one of the best converters of feed of any farmed animal, but for the industry to grow it needs to become better at retaining key nutrients that it is fed. This can be done through more strategic use of feed ingredients, including from fishery by-products and sustainably-sourced, industrial-grade fish such as sand eels”, said Dr Richard Newton of the Institute of Aquaculture, ̽��ֱ�� of Stirling, whose team also included Professor Dave Little, Dr Wesley Malcorps and Björn Kok.

“It was interesting to see that we’re effectively wasting around 80% of the calcium and iodine from the feed fish – especially when we consider that women and teenage girls are often not getting enough of these nutrients”.

Willer said “These numbers have been underacknowledged by the aquaculture industry’s standard model of quoting Fish In Fish Out (FIFO) ratios rather than looking at nutrients.

̽��ֱ��researchers would like to see a nutrient retention metric adopted by the fishing and aquaculture industries. They believe that if combined with the current FIFO ratio, the industry could become more efficient, and reduce the burden on fish stocks that also provide seafood. ̽��ֱ��team are building a standardised and robust vehicle for integrating the nutrient retention metric into industry practice.

“We’d like to see the industry expand but not at a cost to our oceans,” said Willer.

“We’d also like to see a greater variety of affordable, convenient and appealing products made of wild ‘feed’ fish and fish and salmon by-products for direct human consumption.”

̽��ֱ��research was funded by the Scottish Government’s Rural and Environmental Science and Analytical Services Division (RESAS), a Royal Society ̽��ֱ�� Research Fellowship, a Leverhulme Trust Early Career Fellowship a Henslow Fellowship at Murray Edwards College and the ̽��ֱ�� of Cambridge.

Reference: D. Willer et al. Wild fish consumption can balance nutrient retention in farmed fish Nature Food DOI: 10.1038/s43016-024-00932-z

̽��ֱ��public are being encouraged to eat more wild fish, such as mackerel, anchovies and herring, which are often used within farmed salmon feeds. These oily fish contain essential nutrients including calcium, B12 and omega-3 but some are lost from our diets when we just eat the salmon fillet.

Making a few small changes to our diet around the type of fish that we eat can go a long way to changing some of these deficiencies and increasing the health of both our population and planet

Dr David Willer, Zoology Department

Joff Lee / ̽��ֱ��Image Bank / Getty

Mackerel with potato salad

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Innovative aquaculture system turns waste wood into nutritious seafood

jg533 — Mon, 20 Nov 2023 10:00:05 +0000

These long, white saltwater clams are the world’s fastest-growing bivalve and can reach 30cm long in just six months. They do this by burrowing into waste wood and converting it into highly-nutritious protein.

̽��ֱ��researchers found that the levels of Vitamin B12 in the Naked Clams were higher than in most other bivalves – and almost twice the amount found in blue mussels.

And with the addition of an algae-based feed to the system, the Naked Clams can be fortified with omega-3 polyunsaturated fatty acids - nutrients essential for human health.

Shipworms have traditionally been viewed as a pest because they bore through any wood immersed in seawater, including ships, piers and docks.

̽��ֱ��researchers developed a fully-enclosed aquaculture system that can be completely controlled, eliminating the water quality and food safety concerns often associated with mussel and oyster farming.

And the modular design means it can be used in urban settings, far from the sea.

“Naked Clams taste like oysters, they’re highly nutritious and they can be produced with a really low impact on the environment,” said Dr David Willer, Henslow Research Fellow at the ̽��ֱ�� of Cambridge’s Department of Zoology and first author of the report.

He added: “Naked Clam aquaculture has never been attempted before. We’re growing them using wood that would otherwise go to landfill or be recycled, to produce food that’s high in protein and essential nutrients like Vitamin B12.”

Scientifically named Teredinids, these creatures have no shell, but are classed as bivalve shellfish and related to oysters and mussels.

Because the Naked Clams don’t put energy into growing shells, they grow much faster than mussels and oysters which can take two years to reach a harvestable size.

̽��ֱ��report is published today in the journal Sustainable Agriculture.

Wild shipworms are eaten in the Philippines - either raw, or battered and fried like calamari. But for British consumers, the researchers think Naked Clams will be more popular as a ‘white meat’ substitute in processed foods like fish fingers and fishcakes.

“We urgently need alternative food sources that provide the micronutrient-rich profile of meat and fish but without the environmental cost, and our system offers a sustainable solution,” said Dr Reuben Shipway at the ̽��ֱ�� of Plymouth’s School of Biological & Marine Sciences, senior author of the report.

He added: “Switching from eating beef burgers to Naked Clam nuggets may well become a fantastic way to reduce your carbon footprint.”

̽��ֱ��research is a collaboration between the Universities of Cambridge and Plymouth, and has attracted funding from sources including ̽��ֱ��Fishmongers’ Company, British Ecological Society, Cambridge Philosophical Society, Seale-Hayne Trust, and BBSRC

̽��ֱ��team is now trialling different types of waste wood and algal feed in their system to optimise the growth, taste and nutritional profile of the Naked Clams – and is working with Cambridge Enterprise to scale-up and commercialise the system.

Reference

Willer, D F et al: ‘Naked Clams to open a new sector in sustainable nutritious food production.’ Sustainable Agriculture, Nov 23. DOI: 10.1038/s44264-023-00004-y

Researchers hoping to rebrand a marine pest as a nutritious food have developed the world’s first system of farming shipworms, which they have renamed ‘Naked Clams’.

Naked Clams taste like oysters, they’re highly nutritious and they can be produced with a really low impact on the environment.

Dr David Willer

̽��ֱ�� of Plymouth

Naked Clams in wooden growth panel

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Small-scale octopus fisheries can provide sustainable source of vital nutrients for tropical coastal communities

sb726 — Thu, 26 Jan 2023 15:23:51 +0000

Research led by Cambridge scientists, and published in Nature Food, shows that tropical small-scale octopus fisheries offer a sustainable source of food and income to communities that face food insecurity, where the prevalence of undernourishment can exceed 40% and stunting in children under five commonly exceeds 30%.

̽��ֱ��high micronutrient density of octopus - including vitamin B12, copper, iron and selenium - means that human populations only need to eat a small quantity to supplement a diet primarily comprising staple plant crops. ̽��ֱ��new research shows that just a small amount of production in a tropical small-scale octopus fishery can deliver the micronutrient needs to a relatively large number of people.

̽��ֱ��fast growth and adaptability of octopuses to environmental change can also facilitate sustainable production, and catch methods in the fisheries - primarily consisting of hand techniques, small-scale lines, pots and traps - are less environmentally harmful than those of large industrial fishing.

Dr David Willer, lead author, from the Department of Zoology at the ̽��ֱ�� of Cambridge and a Fellow at Murray Edwards College, said: “Worldwide, nearly half of people’s calories come from just three crops – rice, wheat, and maize - which are high energy, but relatively low in key nutrients. Just a small serving of something very, very micronutrient rich, like octopus, can fill critical nutritional gaps. And, of course, if you get better nutrition as a child you’re much more physically and mentally prepared for later life, which can lead to better jobs, better employment and better social development.

“These small fisheries also provide an income and a livelihood, often to women whose economic status is enhanced as a result. Small-scale octopus fisheries revolve around local communities and potentially that gives them a greater resilience against market pressures and other disruptions to global food supply and trade.”

Small-scale fisheries, across all sectors, currently provide more than two-thirds of the fish and seafood destined for human consumption worldwide, and employ over 90% of fishers involved in capture fisheries. 47% of the workforce employed in these fisheries are women.

Based on a global review of data from global seafood databases and published literature, and written in partnership with science-led social enterprise Blue Ventures, the research found that in many cases tropical small-scale octopus fisheries are operating using relatively low impact techniques, and when combined with local and national management approaches can provide a more sustainable source of seafood. Successful approaches include periodic fishery closures, size restrictions, and licences. ̽��ֱ��need for knowledge transfer of fishing gears is also crucial so that the message on fish sustainability and securing the food supply and economic stability is spread widely.

Undernourished coastal communities in the tropics - where children’s growth can be stunted by a lack of micronutrients – can get the vitamins and minerals they need from sustainable small-scale octopus fisheries, say researchers.

Just a small serving of something very, very micronutrient rich, like octopus, can fill critical nutritional gaps.

Dr David Willer, Department of Zoology

Blue Ventures

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Nutritious fish stocks are being squandered by salmon farming, say scientists

jg533 — Tue, 01 Mar 2022 19:00:06 +0000

Scientists studying the Scottish salmon farming industry say that using only fish by-products - such as trimmings - for salmon feed, rather than whole wild-caught fish, would deliver significant nutritional and sustainability gains.

This would allow 3.7 million tonnes of fish to be left in the sea, and enable global annual seafood production to increase by 6.1 million tonnes.

̽��ֱ��study, led by a team of scientists from the Universities of Cambridge, Lancaster and Liverpool and environmental NGO Feedback Global is published today in the journal PLOS Sustainability and Transformation.

As the world’s fastest growing food sector, aquaculture is often presented as a way to relieve pressure on wild fish stocks. But many aquaculture fish - such as Atlantic salmon - are farmed using fish oil and meal made from millions of tonnes of wild-caught fish, most of which is food-grade and could be eaten directly to provide vital nutrition.

̽��ֱ��team collected data on fish nutrient content, fishmeal and fish oil composition, and salmon production, and examined the transfer of micronutrients from feed to fish in Scotland's farmed salmon industry. They found that over half of the essential dietary minerals and fatty acids available in wild fish are lost when these fish are fed to farmed salmon.

Dr David Willer, a researcher in the ̽��ֱ�� of Cambridge’s Department of Zoology and first author of the paper, said: “Fish and seafood provide a vital and valuable micronutrient-rich food source to people worldwide, and we must make sure we are using this resource efficiently. Eating more wild fish and using alternative feeds in salmon farms can achieve this.”

̽��ֱ��team developed various alternative production scenarios where salmon were only produced using fish by-products, and then added more wild-caught fish, mussels or carp for human consumption. All scenarios produced more seafood that was more nutritious than salmon, and left 66-82% of feed fish in the sea.

Feedback’s Dr Karen Luyckx said: “If we want to feed a growing global population well and sustainably, we must stop catching wild fish to feed farmed fish. Until the salmon industry kicks its wild-caught fish oil and fishmeal habit, chefs and retailers should help citizens switch away from unsustainable salmon by offering ultra-nutritious mussels and small oily fish instead.”

Based on their findings on the Scottish salmon industry, the researchers collected global salmon, fishmeal and oil production data to apply their alternative scenarios at a global scale. One scenario shows that farming more carp and less salmon, using only feed from fish by-products, could leave 3.7 million tonnes of wild fish in the sea while producing 39% more seafood overall.

̽��ֱ��authors caution that not enough is known about the source and species composition of fishmeal, but there are positive signs that the use of plant-based feeds is growing.

Dr James Robinson of Lancaster ̽��ֱ�� said: “Aquaculture, including salmon farming, has an important role in meeting global food demand, but nutritious wild fish should be prioritised for local consumption rather than salmon feed, particularly if it is caught in food-insecure places.

“Support for alternative feeds can help this transition, but we still need more data on the volumes and species used for fishmeal and fish oil, as this can show where salmon farming places additional pressure on fish stocks.”

Ultimately, the authors call for a reduction in marine aquaculture feeds, as this will offer opportunities to produce more nutritious seafood while reducing pressure on marine ecosystems.

Willer added: “If we want to feed the growing global population well and sustainably, we must stop catching wild fish to feed farmed fish. There is an urgent need for the food industry to promote consumption of more sustainable seafood species - like mussels or carp - that don’t require other fish as feed.”

This research was funded by the Cambridge Philosophical Society, via a Henslow Fellowship to David Willer.

Reference
Willer, D.F., et al: ‘Maximising sustainable nutrient production from coupled fisheries-aquaculture systems.’ PLOS Sustainability and Transformation, 2022. DOI: 10.1371/journal.pstr.0000005

Adapted from a press release by Feedback Global.

Eating wild-caught fish instead of using it as feed in salmon farming would allow nearly four million tonnes of fish to be left in the sea, while providing an extra six million tonnes of seafood for human consumption, a study finds.

If we want to feed the growing global population well and sustainably, we must stop catching wild fish to feed farmed fish.

David Willer

Fengyou Wan on Unsplash

Shoal of fish

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Scientists supercharge shellfish to tackle vitamin deficiency in humans

ta385 — Mon, 20 Jul 2020 07:00:00 +0000

Over two billion people worldwide are nutrient deficient, leading to a wide range of serious health problems. Fortifying food with micronutrients is already an industry standard for enhancing public health but now scientists at Cambridge’s Department of Zoology have teamed up with Cambridge-based company BioBullets to supercharge one of the world’s most healthy and sustainable sources of animal protein: bivalve shellfish such as oysters, clams and mussels.

Dr David Aldridge and PhD student David Willer have produced the world’s first microcapsule specially designed to deliver nutrients to bivalves which are beneficial to human health. These “Vitamin Bullets” – manufactured under patent by Aldridge’s company, BioBullets – are tailored for optimal size, shape, buoyancy and to appeal to shellfish.

This breakthrough, described in a study published today in the journal Frontiers in Nutrition, is particularly valuable because when we eat bivalves, we consume the entire organism including its gut, meaning that we digest the nutrients which the animals consumed towards the end of their lives. This makes bivalve shellfish the ideal target for nutritional fortification.

In their Cambridge laboratory, the scientists trialled Vitamin A and D fortified microcapsules on over 100 oysters to identify the optimal dose. They also established that this should be fed for 8 hours towards the end of “depuration”, the period in which bivalves are held in cleansing tanks after being harvested.

̽��ֱ��team found that fortified oysters delivered around 100 times more Vitamin A, and over 150 times more Vitamin D, than natural oysters. Even more importantly, they dramatically outperformed salmon, one of the best natural sources of these vitamins. ̽��ֱ��fortified oysters provided more than 26 times more Vitamin A and over four times more Vitamin D than salmon. ̽��ֱ��scientists found that a serving of just two of their supercharged shellfish provided enough Vitamin A and D to meet human Recommended Dietary Allowance (RDAs).

Vitamin A and D deficiencies pose a particularly serious public health challenge – in Ghana more than 76% of children are Vitamin A deficient, causing widespread mortality and blindness. In India, 85% of the population is Vitamin D deficient, which causes cardiovascular diseases, osteoporosis, and rickets. Even in the US, over 40% of people are Vitamin D deﬁcient.

David Willer said: “We have demonstrated a cheap and eﬀective way to get micronutrients into a sustainable and delicious source of protein. Targeted use of this technology in regions worst affected by nutrient deficiencies, using carefully selected bivalve species and micronutrients, could help improve the health of millions, while also reducing the harm that meat production is doing to the environment”.

David Aldridge said: “We are very excited about BioBullets’ potential. We are now establishing links with some of the world’s biggest seafood manufacturers to drive a step change in the sustainability and nutritional value of the seafood that we consume.”

Bivalves have a higher protein content than beef, are a rich source of omega-3 fatty acids, and have some of the highest levels of key minerals of all animal foods. Nevertheless, the nutrients that they deliver naturally is unlikely to solve global deﬁciencies. These shellfish are also highly sustainable to farm, having a far lower environmental footprint than animal meat or ﬁsh, and lower even than many plant crops such as wheat, soya, and rice.

Bivalves are a highly aﬀordable food source when produced at large scale and the global market is rapidly expanding. Production in China alone has grown 1000-fold since 1980 and there is great potential to sustainably expand bivalve aquaculture worldwide, with over 1,500,000 km² available for sustainable low-cost industry development, particularly around the west coast of Africa and India.

̽��ֱ��researchers point out that consumers in poorer regions where vitamin deﬁciencies are most prevalent are more likely to buy slightly more expensive fortified food than to make additional purchases to take supplement pills. They calculate that fortification adds just $0.0056 to the cost of producing a single oyster.

David Willer is supported by the Biotechnology and Biological Sciences Research Council; and David Aldridge is supported by ̽��ֱ�� ̽��ֱ�� of Cambridge, St Catharine’s College and Corpus Christi College.

Reference:

D.F. Willer & D.C. Aldridge, ‘Vitamin bullets. Microencapsulated feeds to fortify shellfish and tackle human nutrient deficiencies’, Frontiers in Nutrition (July 2020). DOI: 10.3389/fnut.2020.00102

Cambridge scientists have developed a new way to fortify shellfish to tackle human nutrient deficiencies which cause severe health problems across the world. ̽��ֱ��team is now working with major seafood manufacturers to further test their microencapsulation technology, or “Vitamin Bullets”.

Targeted use of this technology in regions worst affected by nutrient deficiencies ... could help improve the health of millions

David Willer

Image by Yung-pin Pao from Pixabay

Oysters

Read on

Learn more about the work of David Willer and Dr David Aldridge in this feature.

Yes

̽��ֱ��world's their fish finger

jg533 — Thu, 12 Mar 2020 14:07:27 +0000

Smothered in ketchup or squished into a sandwich, there’s one tasty convenience food that’s hard to resist. Now two Cambridge researchers believe that a twist on the classic fish finger might help address the challenge of sustainably feeding our global population.