Scientists genetically engineer PRRS-resistant pigs
Scientists in Scotland have discovered a way to genetically engineer pigs to be resistant to one of the mostly costly livestock diseases in the world.
The researchers found they can change the genetic make-up of pigs to make them entirely immune to porcine reproductive and respiratory syndrome (PRRS), without having any other effect on the animals.
They hope that the development will improve pig herd health and reduce costs associated with the virus, which accounts for $2.5 billion (£1.75 billion) each year in lost revenue in the US and Europe alone.
The virus, which causes breathing problems and deaths in young animals — as well as miscarriages in pregnant sows — infects animals using a receptor on their cell’s surface called CD163.
By deleting a small section of the CD133 gene, which the virus attaches to, researchers at the University of Edinburgh’s Roslin Institute found they can produce animals which show no symptoms or traces of infection when they are exposed to the virus.
What’s more, the animals show no signs that changing their DNA impacted their health, fertility or well-being.
Dr. Christine Tait-Burkard, one of the scientists behind the study, said the findings could result in production systems which are less costly and have higher welfare standards for animals.
“The PRRS virus evolves rapidly, meaning vaccinations are always a step behind the disease,” she said
“However, making them genetically resistant means the pigs are healthier, while producers won’t have to use other treatments such as vaccination.”
But while the results are exciting for pig producers, Tait-Burkard said it will be some time before the technology can be used commercially.
“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,” she said.
“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 (GM) animals are banned from the food chain in Europe. However, it is not clear what regulations would apply to gene-edited animals, as the approach is different.
While GM techniques can involve introducing genes of other species into an animal, gene editing speeds up processes that could occur naturally through breeding over many generations.
The study is published in the latest issue of the Journal of Virology.
To view the abstract, click here.
Posted on July 30, 2018