Livestock News

Scientists find gene-edited pigs are resistant to PRRS virus


Scientists have cracked the code in fighting one of the most devastating viruses in the pork industry and it’s all through gene-edited pigs. Researchers at the University of Edinburgh’s Roslin Institute have produced pigs that can resist Porcine Reproductive and Respiratory Syndrome, or PRRS, by changing their genetic code.

Tests with the virus found the gene-edited pigs do not become infected at all. And the animals show no signs that the change in their DNA has had any other impact on their health or wellbeing.

PRRS costs the pig industry around $2.5 billion each year in lost revenue in the US and Europe alone. The disease causes breathing problems and deaths in young animals and if pregnant sows become infected, it can cause them to lose their litter.

The virus infects pigs using a receptor on their cells’ surface called CD163. Researchers used gene editing techniques to remove a small section of the CD163 gene. They focused on the section of the receptor that the virus attaches to, leaving the rest of the molecule intact. The team collaborated with Genus PLC, a leading global animal genetics company, to produce pigs with the specific DNA change.

Previous studies had shown that cells from these animals were resistant to the virus in lab tests. This is the first time researchers have exposed these pigs to the virus to see if they become infected.

They found that none of the gene-edited pigs became ill when exposed to the virus. Blood tests found no trace of the infection.

Other groups have used gene editing to create PRRS-resistant pigs by removing the whole CD163 receptor. Removing only a section of CD163 allows the receptor to retain its ordinary function in the body and reduces the risk of side effects, the researchers say.

Dr Christine Tait-Burkard, of the University of Edinburgh’s Roslin Institute, said: “These results are exciting but it will still likely be several years before we’re eating bacon sandwiches from PRRS-resistant pigs.

“First and foremost we need broader public discussion on the acceptability of gene-edited meat entering our food chain, to help inform political leaders on how these techniques should be regulated.

“We also need to carry out longer term studies to confirm that these genetic changes do not have any unforeseen adverse effects on the animals.

“If these studies are successful and the public are accepting of this technology, we would then be looking to work with pig breeding companies to integrate these gene edits into commercial breeding stocks.”

Genetically modified animals are banned from the food chain in Europe. It is not clear what regulations would apply to gene-edited animals, however, as the approach is different.

Tags: Livestock News, Genetic Modification, Agriculture
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