🇳🇴 Scientists make guide for assessing gene editing

Press release from Nofima

December 20, 2023
384

It all started with finding a solution to prevent salmon lice infection and harm. The cooperation between scientists from a range of different disciplines and backgrounds is now providing lessons that will help improve the welfare, health and sustainability of many other animals and plants.

Nick Robinson and Diego Robledo, along with their collaborators from Nofima, Deakin University and the University of Edinburgh, have created a useful guide for assessing the use of gene editing. Photo: Georg Mathisen / Nofima.

“We are trying to understand the genetic mechanisms that affect how salmon become resistant to lice”, says Robinson.

He is Australian and a senior scientist at Nofima in Norway, and he has just settled down in a chair in an office in Scotland. Accompanying him is Diego Robledo. He comes from Spain, but he conducts research at the Roslin Institute at the University of Edinburgh. The project that Nick Robinson leads really is international.

Lice and salmon

Sea lice live by eating skin and blood. Salmon become sick and lice are a problem both for fish welfare and for the industry. But there are salmon that do well against salmon lice:

“In wild coho salmon, this occurs naturally. The cells of the salmon surround the lice and kill them”, explains Diego Robledo.

Coho and also pink are two salmon species native to the Pacific Ocean that combat sea lice naturally in a way that Atlantic salmon (the salmon we know from Norwegian rivers and fish farms) are unable to manage.


Lice attach to the Atlantic salmon skin and feed on blood and mucus. If untreated, the parasites can create sores that stress and can ultimately lead to death of the fish..

About sea lice

Sea lice are small parasites, adults six to twelve millimetres long, that feed on the skin and blood of salmonids. When the skin and protective mucous layer are damaged by adult lice, the fish are weakened and become more prone to infections.


Welfare and survival

“Our genomic research is helping us to understand which genes are involved in providing resistance against sea lice in the Pacific salmon species, and the next step in our project is to test the function of these genes in Atlantic salmon using gene editing. Early next year, we will be ready to introduce gene edited Atlantic salmon to sea lice in a closed biosecure facility. We want to see whether small and precise changes disrupting the function of these genes can cause the immune cells in Atlantic salmon to encapsulate the lice and kill them, like occurs in coho, or to prevent attachment like occurs in pink salmon”, says Nick Robinson.

He emphasises that there is no question of the project editing genes in fish that are going to be grown in the ocean, sold and eaten. The scientists will test which genes can affect whether salmon are able to repel lice infestation. They will look at what happens exactly where the lice attach themselves to the salmon and the importance of genes in relation to stopping the lice.

“The benefits could be large in the future if it is possible to use the knowledge gained from the project to produce a resistant salmon. Lice create wounds that become infected. If we can help the fish to become resistant to lice, it has benefits for fish welfare. By potentially changing the whole epidemiology of lice infection on farms we could also relieve the lice pressure on wild salmon”, he says.

Salmon lice are also more tempted to settle on Atlantic salmon than on other salmon species, such as pink salmon. If scientists find out why, it can help salmon avoid lice altogether.

Risks and benefits

In the project, the scientists will edit genes that their research suggests will keep salmon healthy and the lice away. However, is gene editing safe to use on salmon that are to be farmed and sold? ”In each instance, there needs to be a thorough evaluation of how the edit might affect the welfare and health of the fish, the aquatic ecosystem and society. This should involve consumers and other interest groups in the decision-making process. The benefits should be weighed in relation to any potential harms”, say Robinson and Robledo.

Therefore, they have written a guide along with their collaborators from Nofima, University of Edinburgh and Deakin University in Australia, (A guide to assess the use of gene editing in aquaculture) that helps assess the risks of gene editing.

 

“The guide was written to help assess risks and benefits so that informed decisions can be made”, says Robledo. “How to edit the genes, how to make gene editing part of a research programme, how case-by-case applications might affect wild animals, how society views the approach, what benefits it might bring to animal health and welfare, ecology, environmental footprint, human nutrition, and local communities?”

“The changes we are making are quite small. We don’t take genes from other animals, we make slight adjustments to the genes that salmon already have”, explains Robinson.

Pigs and cucumber

Their gene editing guide can just as easily be used on other fish, animals and plants. “We focus on aquaculture, but the guide is just as relevant for other species”, says Robledo. “The questions that need to be asked are the same for livestock or plants. We haven’t seen anything like this guide to gene editing risk assessment published or proposed for these other food species”, says Robinson.

The scientists emphasise that gene editing should not replace regular breeding. This is where you select animals with the best genetic variants for the traits you want, and breed these animals in favourable combinations, so that the best genetic variants are passed on the next generation.

More about the projects behind the research

CrispResist
Harnessing cross-species variation in sea lice resistance

Do Pacific salmon species carry a secret they could share with Atlantic salmon? What is it in the genes that make these relatives of Atlantic salmon less susceptible to lice? Researchers is looking for the answers to these questions, using the gene editing method CRISPR-Cas9.

PERIOD 2021 – 2024

FUNDED BY The Norwegian Seafood Research Fund – FHF

 

NoLice
Novel tools and knowledge for a future with no lice infestations in Norwegian aquaculture

The overall aim of this project is to identify naturally produced compounds that are associated with Atlantic salmon susceptibility and resistance to two parasitic sea lice species and to develop tools that can be applied to boost Atlantic salmon resistance and reduce lice infestation in Norway.

PERIOD 2021 – 2024

FUNDED BY The Research Council of Norway

Contact person

Portrait of Nicholas Andrew Robinson

Nicholas Andrew Robinson

Senior Scientist


Originally published on 18 December by Nofima.

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