Do You Like Your Chicken Extra CRISPR?

Last month I wrote about some scary new changes that the poultry industry is fighting hard to bring about. Industry is hoping to ditch a long-standing USDA regulation that mandates any chickens with lesions discovered during processing must be “condemned” and not sent forth into the food supply.

Those lesions, or tumors, which can appear internally or on the skin of a bird (and, according to some experts are not merely cosmetic, but systemic as well), are tell-tale signs of a devastating and deadly retrovirus called avian leukosis. Current USDA rules require that such diseased birds are not fit for consumption and must be disposed of.

Enter the National Chicken Council (NCC), which believes that such rules are ridiculous, a waste of good food and an unnecessary delay in processing time. Oh, and avian leukosis isn’t really a problem in the poultry industry anymore, but… should a chicken have the disease, it’s fine and dandy to just cut any tumors off and send the bird down the line. Apparently the NCC wants consumers to have a choice over which selling point they feel most comfortable sitting down to dinner with.

But here’s where things get really interesting: While the NCC claims that avian leukosis is basically nonexistent these days, scientists have been scrambling to genetically “fix” chickens so that they are no longer susceptible to the disease.

Utilizing the controversial, powerful, and highly sophisticated genetic editing method known as CRISPR, researchers first attempted to alter “primordial germ cells” from chickens, inserting those altered cells back into chick embryos. That was in 2016, and the method failed more often than it succeeded.

chicken test tube
Chicken in formaldehyde

But Jiri Hejnar, group leader at the laboratory of viral and cellular genetics at the Czech Academy of Sciences, thinks he may have cracked the egg problem.

Three years ago Hejnar (who is quoted as saying that avian leukosis is a problem for poultry farmers around the world) took those altered germ cells and used them to restore fertility in previously sterilized young roosters (called cockerels), which enabled him to create a cockerel that hatches with a specific gene deleted. That, Hejnar claims, has allowed him to produce a flock of genetically modified “white leghorn chickens” that are immune to avian leukosis.

Now, CRISPR, aside from its remarkable potential to cure humans of genetic diseases, comes with a lot of unknown risks. As biotech expert Dr. Greg Licholai told Yale Insights recently “we think we know what we’re doing…but there’s always the possibility that either we miss something or our technology can’t pick up on other (inadvertent) changes that have been made.”

What kind of uh-oh changes is the doctor referring to? Uncontrollable mutations that could create “incurable disease(s)” or even antibiotic resistance, for starters. Then there’s the issue that it’s reasonable to presume these genetically modified chickens will at some point send their manipulated genes forth to the rest of the poultry world, making a “normal” chicken or turkey or any other fowl a thing of the past.

But knowing if your eggs or drumsticks came from a GM chicken or not (should Hejnar’s fowl go forth in farming) will prove to be even more difficult than determining the GMO status of wheat, corn or any other bioengineered or cross-contaminated foodstuffs.

The Mushroom Chronicles

Another application of CRISPR technology is in crop cultivation. China is working on manipulating rice, the EU is attempting to create wheat with no gluten, and the U.S. is hard at work making CRISPR-modified cacao and oranges. And those are the advanced examples; dozens more from coffee to watermelon are in the works.

Then there are mushrooms — white button mushrooms, to be precise.

Several years ago, Dr. Yinong Yang, a plant pathologist at Pennsylvania State University, used CRISPR to create a white button mushroom that is resistant to bruising and browning. Since Yang’s “frankenfungi,” as it’s been called, were created by deleting genes in the mushroom that produce a browning enzyme – rather than inserting a “foreign” gene, virus or bacteria – it easily zipped by any regulatory scrutiny. In fact, four years ago the USDA announced that it had no intention of regulating the cultivation or sale of Yang’s fungi, which can take its place in the supermarket alongside any other mushroom, no labeling required.

At the time, plant biologists in China applauded the USDA’s sidestep, saying they are “confident” many more crops will fall “outside of regulatory authority.”

And be it fowl or fungi, that seems to be the end goal.

As far as avian leukosis goes, the chicken council is eagerly awaiting the publication of its cancer chicken rule in the Federal Register, at which point consumers and industry alike will be able to comment. We’ll know more next month when the fall agenda is issued.

But be it trimming tumors off the birds or hatching genetically modified ones that may be immune, it sure seems as if avian leukosis is a far bigger issue than industry would like us to believe.

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