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Seaweeds for foods and feeds

Seaweeds grow in all of the Earth’s coastal climatic zones and have numerous colours, shapes and uses. Although consumed widely in Japan as an important dietary source of fibre and vitamins; in the Western hemisphere, they are overlooked as a nutrition source. Maria Hayes, Food Researcher explains

Seaweeds are consumed widely in Asia especially in Japan where they are considered an important dietary source of fibre and vitamins; but, in the Western hemisphere, they are largely overlooked as a source of nutrition. However, in recent years there is interest in their use as a source of protein and as feed ingredients and there are now a number of Irish companies harvesting or producing seaweeds using aquaculture and supplying them as feed and, indeed, food ingredients.

The BioAlgae project

The BioAlgae project at Teagasc is looking at methods to isolate protein from seaweeds using different novel methods and adding more economic value to this natural resource. Seaweeds can contain up to 47% protein based on the dry weight of the seaweed. However, the content can vary depending on the geographical location and season of harvest. This, however, is significantly more than the protein content of milk, which is about 4%. We are using different dairy processing technologies within this project to target seaweed proteins to convert them into food and feed ingredients. Some of the methods that we are using, include “salting-out” the protein with food grade chemicals and enzymatic treatment of the cell wall of seaweeds in order to break this and release the protein from within. The amino acid profile of several seaweed proteins is similar to egg so it could be a source of protein suitable for vegans, vegetarians and the general population if it can be extracted in sufficient quantities in a cost-effective manner using these methods.

EU-funded Seasolutions Project

A second project that we are involved in at Teagasc is the EU-funded Seasolutions project, funded by ERA-NET. This project is focused on identifying seaweeds that are safe and suitable for use in cattle, sheep and dairy cows as a feed additive ingredient that can reduce methane emissions from these agriculturally important livestock. Greenhouse gas emissions are a problem for agricultural production of food currently. However, we believe that seaweeds have potential to solve the problem of greenhouse gas emissions and improve the health and well-being of our dairy cows, cattle and sheep. Several studies were carried out previously in Australia and New Zealand, as well as Canada, focussed on the use of the red alga Asparagopsis taxiformis to reduce methane emissions from farm animals. These studies found that addition of 0.5-2% dry weight of this seaweed in the feed of farm animals could reduce methane emissions by as much as 98% from the animals. The active agent that is responsible for this reduction is bromoform. This is all very positive but there are caveats concerning its use. Firstly, Asparagopsis taxiformis is not native to Ireland and is difficult to source in large quantities suitable for use in animal feeding trials here. Secondly, bromoform is a carcinogenic agent and its inclusion in animal feed is disputed; and thirdly bromoform production from this seaweed is thought to have a negative impact on the ozone layer. Because of this, the Seasolutions project is looking at other bioactives in seaweeds that are available in abundance in Ireland and their potential to reduce methane emissions from livestock.  These seaweeds must be cost suitable for production of any additive ingredient and must be safe for use in livestock. This project started in March 2020 and will run for three years and we have several international collaborators in EU and Canada. We are using sustainably sourced seaweeds from Irish companies in Ireland as part of this project.


To find out more about Seaweeds you can listen to Maria Hayes being interviewed (c. 18.15 mins in) on a special episode of the Research Field Podcast. Listen to the Research Field Podcast Special Episode: Science Week 2020 here  https://teagasc.ie/publications/tresearch/the-research-field/

Teagasc held a series of exciting virtual events for Science Week (November 8-15) as part of ‘The Festival of Farming and Food – SFI Science Week at Teagasc’. The core theme for Science Week 2020 is ‘Science Week - Choosing our Future’ focusing on how science can improve our lives in the future, and in the present. This will explore how science can help us to make positive choices that will impact the environment, our health, and our quality of life. Changes based in scientific evidence that we make today can hugely improve our future life, but also right now. Watch the events back here.

We’d love to hear from you. Be part of The Festival of Farming and Food journey on Social Media: @Teagasc @ScienceWeek #FestFarmFood #BelieveInScience #ScienceWeek