Will gene editing ever take off in pig production?

Caroline Stocks investigates how the technique could help deliver a PRRS-free future – if public perception changes

It’s been hailed as the next major development for livestock breeding and production.

Giving scientists the ability to make precise genetic changes which would ordinarily take years of selective breeding to achieve, gene editing has the potential to enable significant improvements, particularly in the battle against disease.

But given Europe’s track record of caution when it comes to new farming technologies – particularly where food is involved – the question of whether gene-edited pigs will be seen any time soon is a tricky one.

It’s a situation not helped by European legal experts. Recently, the European Court of Justice (ECJ) ruled that organisms obtained by mutagenesis – a process which improves a plant or animal’s characteristics without introducing foreign DNA – must be classed as genetically modified (GM).

By deciding that gene editing makes changes to genetic material that wouldn’t occur naturally, the court placed the technology under the stringent GMO Directive: a tough piece of legislation set out in the 1980s that has resulted in GM technology being all but shut out of the EU.

It was a blow to Europe’s scientific community, with some scientists claiming the decision had put the technology out of reach of European farmers, consigning them to a generation of being disadvantaged against their competitors.

While much of the focus has been on crops, for many in the pig sector the ruling was particularly frustrating, given that just weeks before, scientists at the Roslin Institute had been hailing the development of PRRS-resistant pigs, produced using the technique. Gene editing had been used to remove a small section of the CD163 gene, which acts as a receptor for the PRRS virus on the surface of pigs’ cells. When exposed to the virus, none of the animals became ill.

“The work on PRRS could offer a solution to a disease that’s really troublesome for pig producers around the world, and it would have a huge impact on pig health and welfare,” said Georgina Crayford, NPA senior advisor. “Not only that, it could be beneficial to public health, too, in terms of antibiotic use and antimicrobial resistance.

“The ECJ’s ruling is frustrating and it’s something academics now have to navigate, but the biggest disappointment is that the conversation was around GM. It has frightened consumers before they could understand what it means and before scientists could complete their research.”

But Helen Browning, Soil Association chief executive and organic pig producer, said the decision was undoubtedly the right one.

“We have always been clear that this technology should be seen as a GM,” she said. “We still know comparatively little about it. DNA has a purpose at a specific time, and the process of selecting genetic structures and making changes could have unintended consequences.”

Mrs Browning’s primary concern is that the technology could be used by the pig sector to ‘engineer its way out of trouble’, rather than looking at ways to improve husbandry and biosecurity.

“Instead of putting on a sticking plaster, we should be addressing the problems of our pig systems and looking to get the basics right,” she added.

“We already have the tools to get that balance between productivity and welfare right, so I’m not sure what being without the technology won’t allow producers to do.”

Christine Tait-Burkard, one of the Roslin scientists behind the PRRS-resistant pig project, has some sympathy with these views – and with the ECJ’s ruling.

“It’s a biotechnology – people have been frightened by the GM discussion and we’ve not properly recovered from that,” she said. “Even though many animals eat GM feed, people are still wary.

“If you look at the letter of the law, it’s about the modification of the genome, so I don’t think the ECJ could have ruled any differently – it’s the European Parliament that needs to define what’s in the law.

“If the court had said it’s not GM, then it would have put us in a different limbo, because what is it then?

“Even though it’s a different technology, it’s better that it’s going through this public discussion. People are afraid of it, but by informing them, it will hopefully make them amenable to it.”

Bill Christianson, chief operating officer of PIC – a subsidiary of global livestock genetics leader Genus, which has invested in gene editing, such as at the Roslin PRRS project – said that while he understands the concerns, consumer and government caution shouldn’t stop research into the field or prevent pig producers from utilising the technology in the long-term.

“The ECJ ruling lumped gene editing with GM, which we don’t agree with, but we will be pragmatic and keep going,” he said. “Gene editing is a technology with huge potential, and we are investing millions of dollars to see that it’s developed properly.

“I do think it will become more acceptable – as a company we wouldn’t be investing at this level otherwise.”

Given Europe’s reputation for caution around new technologies, Dr Christianson said transparency is a critical component of gaining consumer, business and government acceptance – something PIC is working hard on.

“We are a responsible company and we’re not going into this naïvely: we recognise there’s a need to engage with regulators and scientists around the world to make sure we are doing it properly, and we also need to get it accepted by industry and consumers,” he added.

“It starts with putting ourselves in consumers’ shoes. It’s one thing to talk about the benefits to us as company, or to farmers, but that doesn’t resonate. We need to talk about the benefits to them and to animals. We want to be transparent, but we don’t want to confuse people and we are spending a lot of time engaging ahead of time. We’re not near commercialisation yet, but we’re learning from the GM situation to understand the right way to discuss this.”

It’s also possible that Brexit could encourage more discussion about the tools UK farmers have available to them.

Farming minister George Eustice has said in the past that gene editing has the potential to improve the country’s ability to breed plants and animals with beneficial traits, ‘thereby contributing to making food production more efficient and sustainable’. He and Defra Secretary Michael Gove have both suggested that Brexit could offer the opportunity for the UK to embrace the technology, even if the EU doesn’t.

But while Defra said it would continue to take a science-based approach to regulation following the ECJ’s ruling, Dr Crayford said it’s important not to expect too much, too quickly. “Brexit offers a glimmer of hope that there could be some regulatory leniency, but it depends what deal we get and how tied we will be to regulations.

“Although it’s frustrating, the jury is still out,” she said. “Ultimately, whether gene editing is embraced in the UK will come down to what consumers are prepared to eat, and whether the GM label has scared them away.”

Mrs Browning. added: “Government and business will be led by consumer demand and how people feel about the technologies.

I don’t think there’s any sense that people are looking for this in their food.”

However, Dr Tait-Burkard said it’s important to take a longer- term view about when and how – rather than if – the technology will be used on farms.

“From a practical perspective, it will take another 7-10 years [for the PRRS technology]to go through the testing process and get it into pig breeding systems, and perceptions might have changed by then,” she said. “We need to engage with the public and talk to them about what the technology is, and with time it will get better. We do a lot of engagement with schools now where they learn about genetics, so they don’t see it as threatening.

“As that understanding grows, there will hopefully be more acceptance, and we will start seeing this technology used on farms to help pigs.”

What is gene editing?
While genetic modification involves inserting new genetic material from a different species into a genome, gene editing is a process which is used to alter an animal or plant’s existing DNA to make changes which could occur naturally through years of selective breeding. The most common technique, known as CRISPR-Cas9 – the technique used by Roslin scientists to develop PRRS- resistant pigs – acts as ‘molecular scissors’, which target a specific point on the genome and cut it open.

The cells’ DNA repair the break and introduce changes to one or more gene, enabling scientists to precisely remove, add or alter sections of the DNA sequence, which can alter the genes that determine an animal or plant’s characteristics.

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About The Author

Editor of LBM titles Pig World and Farm Business and group editor of Agronomist and Arable Farmer. National Pig Association's webmaster. Previously political editor at Farmers Guardian for many years and also worked Farmers Weekly. Occasional farming media pundit. Brought up on a Leicestershire farm, now work from a shed in the garden in Oxfordshire. Big fan of Leicester City and Leicester Tigers. Occasional cricketer.