“Keep America First in Agriculture” was launched June 25 by the National Pork Producers Council, stressing the need for establishing the proper regulatory framework for gene editing in livestock across the United States.


According to the National Pork Producers Council, gene editing technology, which introduces useful genetic variation into food animal breeding programs, promises significant animal health benefits, including a natural immunity to disease and a reduction in the need for antibiotic use. (Journal photo by Kylene Scott.)

This innovation will help ensure U.S. farmers have the opportunity to remain competitive in the world market.

“Without an appropriate regulatory framework, we risk U.S. agriculture one of our country’s most competitive economic sectors falling behind other countries,” Jim Monroe, assistant vice president, communications, NPPC said. “The U.S. has always been the global leader in agriculture innovation.”

Alison Van Eenennaam, an animal biotechnology and genomics Extension specialist, University of California-Davis, gave the low down on gene editing and how it works. Gene editors are basically a “very sophisticated pair of scissors,” she said. They look for a very specific piece of DNA.

“Gene editing really offers an approach to precisely introduce useful genetic variation in food animal breeding programs, because these genome editors can go to a precise location based on the DNA sequence,” Van Eenennaam said. “It very precisely introduces a double strand break at that location in the genome.”

Once a break in the genome has been introduced, it can be repaired one of two ways.

“I think it’s important to note that gene editing is really distinct from genetic engineering, because it is very targeted where that double strand breakthrough occurs. And it doesn’t necessarily involve the introduction of foreign DNA,” she said.

A double strand break is repaired by naturally occurring cellular machinery, according to Van Eenennaam, and those breaks are what is responsible for all genetic variation and for evolution.

“It is actually what animal breeders work on when they’re selecting animals—is basically naturally occurring in mutations introduced by naturally occurring breaks,” she said.

Sometimes when there is a deletion or an insertion of a couple of base pairs often inactivates the gene.

“So if you very precisely go in and break a gene that is responsible for a pig, for example, being susceptible to a disease, you can therefore create a pig that’s no longer susceptible to that particular disease or virus,” she said.

And in this case it doesn’t involve introduction of any novel DNA sequences.

In the homology directed repair pathway it depends on what the donor template is, but it “can do things as simple as altering maybe a single base pair from a T to C, which maybe alters the amino acid that’s coated for the triplet code on and alters the proteins coding which can have a desired function,” Van Eenennaam said.

“Or you might use it, for example, to entergress an allele or a form of a gene from one breed of pig to another, or from one breed of cow to another,” she said.

Van Eenennaam’s lab is involved with introducing an allele for not growing horns in dairy cows so they no longer need to be manually dehorned.

“If it’s donor template is from within the species, then that’s really analogous to the type of alterations you can do using conventional breeding by base basically crossing two different breeds together,” she said.

At the end of the day, gene editing really opens up a new opportunity for breeders’ to address critical problems like disease resistance, animal welfare traits— dehorning and resilience—heat tolerance, and product quality traits.

“I think that’s why the global academic community is so excited about the potential to use this in our food animal breeding programs,” Van Eenennaam said.

NPPC’s own Dan Kovich, deputy director of science and technology, said producers are excited to be able to use gene-editing technology once it becomes available.

“Basically, it allows for precise, small changes to specific genes and for example, the pigs genome that can have huge impacts, and particularly on disease resistance,” Kovich said. “As a veterinarian, that’s what excites me most about this technology is it really offers a powerful new tool to combat particularly diseases of livestock that are caused by viruses.”

Kovich said pig producers have been stuck for a long time because they didn’t have the right tools in their toolboxes to combat viruses and the problems they cause.

“There’s some real timely examples of how gene editing could potentially help our industry,” Kovich said.

Porcine reproductive and respiratory syndrome virus is one of those. PRRS causes reproductive losses in sows and eventually impacts their respiratory systems, causing a decrease in the production across the entire cycle.

“This is a disease that we have struggled as an industry,” Kovich said. “As well as really the entire world where there are significant populations of pigs for years. It has up to a billion dollar a year impact here in the U.S..”

Kovich hopes with gene editing, technicians can make a small change—basically knocking out one specific gene in the genome of the pig—and making them resistant to all the strains of PRRS.

“That will really, really revolutionize how we control that particular disease,” Kovich said.

He hopes the same can be done for African swine fever and foot-and-mouth disease.

“I think that it’s, again, producers are excited because it offers benefits in terms of preventing animal deaths, animal suffering and it makes production more sustainable,” Kovich said. “I think there’s also a lot of other public health benefits that are out there too.”

Often when animals get sick with a virus, producers have to follow-up secondary bacterial infections with antibiotics.

“If we can get a handle on viral disease, it will actually lead probably to a big reduction in anti microbial use in agriculture as well,” Kovich said. “So really tremendous benefits that producers should be able to see from this technology, really just by making these small, precise changes within the animals own genome.”

But without this type of technological advancement, food animal production will stagnate, Andrew Bailey, NPPC lead counsel for science and technology, said.

“Unfortunately, despite all of the promise of this technology, our current proposed regular framework for this we are at a huge disadvantage to other countries across the world,” Bailey said.

The Food and Drug Administration has proposed in its draft guidance for industry, No. 187, it is seeking to treat the altered animal genome itself as a drug instead of the actual technology that alters the genome. Bailey said it has done this on the theory that it meets the regulatory definition of intended to affect the structure of the function of the body of the animal. The Center for Veterinary Medicine states that it will do this regardless of the technology used as the genes and whether or not the genomic alterations are heritable.

“Under this guidance, CVM is proposing to consider each specific genomic alteration as a separate new animal drug requiring approval, and they will restrict any new animal drug approvals and food producing animals to the individual animals and their progeny,” Bailey said.

These rules would “require sponsors to seek a separate approval for the same genomic alteration and each new lineage into which it has introduced in the case of heritable genomic alterations,” he said.

CVM would also consider all animals with the altered genome from the same limit lineage to contain an animal drug, including those that acquired the alteration through crossbreeding.

“They would retain the authority over the initially treated animals as well as all the progeny in perpetuity and forever,” Bailey said. “This approach creates, as you might imagine, a host of problems related to on farm and in plant authorities, as well as enormous trade barriers.”

Many other countries are interested in the technology, and some have their own versions already. Diseases such as African swine fever are driving extreme interest in GE livestock across Europe and in China.

“Many other countries and regions are looking to adopt this technology, recognizing the need to update the regulations to accommodate it,” Bailey said.

Bradley Wolter, a leading pork producer and president of The Maschhoffs, a company that produces over 4 million market hogs per year, spoke on behalf of pork producers. He said American pork is some of the most competitive pork across the globe, and has resulted in millions of U.S. jobs and contributes over a trillion dollars to the U.S. economy.

“We’re a critical industry, not only within agriculture, but the whole of the US economic growth,” Wolter said. “It’s been mentioned this morning, one of the big concerns we have as an industry today is the global spread of African swine fever.”

Because of the rapid spread of ASF across the eastern hemisphere, there’s been “significant investment” in the EU and China to explore ways in which gene editing could create a pig that’s resistant to the virus.

“If they’re successful in editing the genome of these animals, they may be protected and spared from the impact of the virus. And consequently, they may be able to eradicate the impact from their pig populations, if this situation were to occur,” Wolter said.

If ASF were to come to the U.S., swine herds would be decimated, creating a large business risk for American producers.

“The concern we have as producers is that the current FDA regulation, as has been highlighted would preclude the use of gene editing here in the U.S. as a means of mitigating that risk today,” he said. “Even though if it were approved as a legitimate technology in one of these other countries that again have begun investment, likely to be successful in our opinion, we would be precluded from using that technology and clearly put our competitive position at risk.”

Pork producers need something like this technology would provide, Wolter said.

“We are dependent upon the gene editing technology as we see it to remain competitive in this space, adding value to the whole of us agriculture, in protecting the competitive advantage of the family farmers that raise pigs throughout the continental U.S. today,” he said.

Kylene Scott can be reached at 620-227-1804 or kscott@hpj.com.

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