Every year, the US raises millions of fish for food, but many of them die of diseases. Theoretically, using genetic engineering to give fish genes that fight disease could cut down on waste and make fish farming less harmful to the environment. A group of experts has tried to reach this goal by putting an alligator gene into the genomes of catfish.
In America, people eat a lot of catfish. In the US in 2021, catfish farms made a total of 307 million pounds (139 million kg) of catfish. Rex Dunham, who works on catfish genetic development at Auburn University in Alabama, says, "On a per-pound basis, anywhere between 60 and 70% of US aquaculture is... catfish production."
But sick organisms also grow well in farms that raise catfish. Dunham says that between the time farmed fish are born and the time they are collected, diseases kill about 40% of animals around the world.
Can a new way of changing genes be helpful?
Dunham's work found that the alligator gene, which makes the cathelicidin protein, could be a solution. Dunham says that the protein has antibacterial qualities that could help keep alligators from getting infections in the wounds they get when they fight each other so violently. Dunham wondered if animals whose DNA had the gene added on purpose might be less likely to get sick.
Dunham and his coworkers also wanted to take things a step further by making sure that the modified fish they made couldn't have offspring. That's because if genetically modified animals get out of fields, they could hurt wild species by eating their food and taking over their homes.
To "try to kill two birds with one stone," transgenic survivors Dunham, Baofeng Su (also at Auburn University), and their colleagues used the gene-editing tool CRISPR to put the alligator gene for cathelicidin into the part of the genome that codes for an important reproductive hormone. Without it, fish can't have babies.
In fact, the fish that come out of it are less likely to get sick. When two types of bugs that cause disease were put into water tanks, fish whose genes had been edited did much better than those whose genes hadn't been changed. Dunham said that, based on the infection, "the survival rate of the cathelicidin transgenic fish was between two and five times higher."
The researchers posted their results online at the preprint server bioRxiv. They also said that the transgenic fish are sterile and can't have babies unless they get shots of hormones that make them fertile. The paper has not yet been reviewed by other people.
"When I heard about the study for the first time, I was shocked. Who would have thought to do that? Greg Lutz, who studies genetics in aquaculture at Louisiana State University and has been doing so for decades, asks, "And why would they?" But Lutz thinks the work has promise because, as he points out, gene editing has been used to reduce waste in farm animals for a long time. Disease resistance can have a big effect on the amount of trash that fish farms make.
He says that growing fish that are resistant to diseases will use less resources and make less waste in general. Lutz is excited about the project, but he isn't sure if CRISPR catfish will be the future of farming. The team's way of changing genes is hard, and it's likely that it would have to be done for every breeding cycle of hybrid catfish, which are often used in aquaculture. He says that it's just too hard to breed enough of these fish to create a strong, genetically sound line.
Getting hungry?
Researchers at Auburn are trying to get their modified catfish approved so that it can be sold and eaten. It can take a long time, though.
In the US, only one other type of fish that has been changed genetically has been allowed. AquaBounty, the company that makes the fish, has gotten approval from the FDA to put AquAdvantage salmon on the US market in 2021. This is after 26 years. The fish are a lot bigger than they would be if an extra gene from another type of salmon hadn't been added to their genome.
Let's say that in the end, the catfish can be sold. Who is going to eat them? Both Dunham and Su agree. Su says that the alligator gene makes a protein that loses its biological function when the fish are cooked. This means that it probably won't hurt the person who eats the fish. In any case, he says, a lot of people eat alligator meat right now. Dunham says, "I'd eat it up in an instant."
But Lutz says that the idea of eating a catfish with an alligator gene could be gross to some people. "I'm sure there will be people who think that catfish will bite them because it has a big mouth and sharp teeth," he says.
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La Shon Y. Fleming Bruce a/k/a SHONSPEAKS is a blogger, thought leader, mental wealth coach for those who are experiencing overwhelm, anxiety, depression or a feeling of not belonging in a world growing in artificial intelligence and are ready to break the chains of the poverty mindset and limitations caused by religious, social and political ideology. I am also certified brain health specialist, and lead creator of https://shonspeaks.org I am also a lawyer and managing member of The Fleming-Bruce Law Firm, P.L.L.C. If you want to check out more of my writings and other video that may not be released on this site, go over to my website at https://shonspeaks.org
La Shon Y. Fleming Bruce a/k/a SHONSPEAKS is a blogger, thought leader, mental wealth coach for those ready to break the chains of a poverty mindset caused by religious, social and political ideologies, a certified brain health specialist, a speaker, and lead creator of https://shonspeaks.org I am also a lawyer and managing member of The Fleming-Bruce Law Firm, P.L.L.C. whose practice areas focus on divorce, custody, probate, car accidents, and bankruptcy.