FDA Approves U.K. Biotech Produced Gene-Edited Pigs for U.S. Consumers

Written by Brenda Baletti, Ph.D. on May 15, 2025. Posted in Current News

The U.S. Food and Drug Administration (FDA) last week gave a U.K.-based biotech company the green light to produce gene-edited pigs for human consumption in the U.S.

PIC, formerly the Pig Improvement Company, uses CRISPR gene-editing technology to genetically engineer pigs to be resistant to porcine reproductive and respiratory syndrome (PRRS), a viral infection that affects pigs produced in industrial factory farms, according to Technology Review.

PRRS, which first emerged in the 1980s, is a contagious respiratory virus that causes fever, respiratory issues and reproductive failure in pigs. It can also suppress the immune system, making pigs more vulnerable to other infections.

A recent analysis showed the virus cost the industrial pork industry about $1.2 billion in lost production between 2016 and 2020. Producers have had difficulty controlling the virus because it mutates quickly, rendering vaccines ineffective.

CRISPR gene editing makes it possible for scientists to manipulate an animal’s own DNA, rather than adding DNA from other species to it, as has been done with previous genetically modified organisms (GMOs).

The FDA’s approval allows the company to produce the pigs commercially, which includes allowing the pigs to reproduce and pass on their genetic modification.

The designers of the pig used the CRISPR gene-editing “scissors” to edit pig embryos, cutting out the molecular receptor the PRRS virus uses to enter the cells. They then implanted the embryos into young female pigs.

“This approval is a milestone in biotechnology, with gene-edited animals potentially offering a more sustainable and disease-resistant source of protein,” wrote Food & Drink International.

Supporters also tout the idea that gene-edited pigs will need fewer antibiotics, because they won’t get sick.

However, critics doubt the editing will work for long. They also raised concerns about the technology’s unintended effects.

GMWatch, a GMO watchdog group that reported the FDA approval in its newsletter, wrote:

“We don’t expect the genetically engineered virus resistance — which even now is leaky — to last long in the gene-edited pigs. We saw in the COVID pandemic just how quickly viruses mutate to evade any barrier placed in their path.

“The genetically altered pigs will drive the evolution of mutations in the virus that enable it to break through the engineered virus resistance — potentially leading to the emergence of even more virulent strains of the virus.”

Swine disease researchers have also raised doubts about whether the gene editing will even work. A retired University of Minnesota professor and veterinarian told AVMA News, “There is no silver bullet when it comes to PRRS.”

“It will hopefully improve the control of PRRS,” he said. “But as it has not been tested under conditions representative of large-scale pork production, producers and veterinarians will still need to apply all the control measures that have been proven to be effective against this virus.”

In response to the news, the Center for Food Safety (CFS) is calling on the FDA to implement stricter regulations on genetically engineered animals. The organization said the current regulatory structure “lacks the necessary rigor and public transparency.”

CFS also said that gene-editing animals can lead to unanticipated animal health issues, environmental disruption, and that without labeling laws, it can take away consumers’ rights to make informed decisions about what they eat.

Other attempts at gene-editing animals … and people

The FDA decision on PIC’s pigs is among the first for gene-edited livestock in the U.S. The process has long raised concerns, because in animals, gene editing has led to unexpected side effects, including enlarged tongues and extra vertebrae.

Often, researchers don’t know the extent of a gene’s functions until they attempt to make changes to it, Dr. Joseph Mercola reported.

Technology Review said the pig-editing project is “scientifically similar” to an attempt in China in 2018 to genetically engineer humans. Scientist He Jiankui edited the embryos of what would become twin girls to make them resistant to HIV by removing a receptor gene.

When the news broke about the twins, there was international outcry. Jankui was sentenced to three years in prison and a hefty financial penalty. It is unclear what happened to the girls. Jiankui told NPR they are “living a normal, peaceful, nondisturbed life,” but declined to comment on whether there had been any negative effects.

An international panel decided no one should modify babies again “until it has been clearly established that it is possible to efficiently and reliably make precise genomic changes without undesired changes in human embryos.”

However, those restrictions don’t apply to pigs.

Raymond Rowland, a University of Illinois researcher involved in creating the first PRRS-proof animals, told Technology Review that gene editing is “in its largest sense, a way to create more perfect life.”

So far, only a few gene-edited animals have been allowed in the U.S. In 2015, the FDA approved AquaBounty Technologies’ application to create and farm its genetically engineered salmon, designed to grow twice as fast as normal salmon.

However, after approval, the company faced opposition from environmental activists and low demand for its product. Last December, it closed its fish factory and culled the remaining stock.

In 2022, the FDA gave gene-edited cattle, developed by bioengineering company Recombinetics, a low-risk determination for marketing products, including meat. The animals have their genes modified to make their coats shorter and slicker, which is intended to help them better withstand heat stress, allowing them to gain more weight and increase the efficiency of meat production.

The FDA said there were no safety concerns and allowed the development to move forward. The low-risk determination means that when the company is ready to market the gene-edited cattle, it will face lower hurdles in the regulatory process.

The same company was attempting to gene-edit cattle in Brazil to be hornless, but found unexpected genomic alterations during the process, which Brazil subsequently halted.

Not the first gene-edited pigs in U.S.

PIC’s pigs are the second genetically modified pigs approved as food in the U.S. In 2020, Revivicor won FDA approval for its GalSafe pigs, edited to be safe for people with the alpha-gal syndrome to eat.

Alpha-gal syndrome sensitizes people to allergic reactions to beef, pork and lamb, usually after a tick bite. The GMO animal was created by removing the gene for alpha-1, 3-galactosyltransferase, which “attaches alpha-galactose sugars to cell surfaces,” Medpage Today reported.

While the GalSafe pigs were for a specialty market, PIC hopes its pigs will be widely adopted across the livestock industry. The company is seeking approval in Canada, Mexico and China and plans to launch sales in the U.S. next year, Food & Drink International reported.

More gene-edited animals are also in the works. Last year, the FDA announced the establishment of two Animal and Veterinary Innovation Centers focused on making genetic alterations to animals that “support agricultural resilience, food security, animal health, or public health.”

The agency provided funding to the University of Wisconsin-Madison to develop gene-edited chickens to resist highly pathogenic avian influenza, also known as bird flu. It also funded the University of California, Davis, to work on various major livestock species for food and to share their data to help ease the regulation process.

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