On Sep. 19 and 20, the Veterinary Medicine Advisory Committee of the U.S. Food and Drug Administration (FDA) met to evaluate the scientific research on the human and environmental health impacts of genetically engineered (GE) salmon. If green-lighted by the FDA, the AquAdvantage Salmon, produced by Aqua Bounty Technologies, Inc., will be the first genetically engineered animal approved for human consumption.
In regular salmon, the growth hormone gene is deactivated when the fish is in cold water, which it is in for most of its life. AquAdvantage, a GE Atlantic Salmon, has been genetically modified with a growth hormone gene from Chinook salmon and a constitutive promoter from pout fish. The constitutive promoter regulates the expression of the growth hormone, and it is on all the time, causing AquAdvantage to grow twice as fast as regular salmon.
Prof. Craig Altier, population medicine and diagnostic science, sits on the committee, which was charged with evaluating whether the GE salmon actually grew faster. They must assess the potential effects of this change on humans, the environment and the fish itself.
Accordingly, the FDA conducted “every study conceivable,” all of which showed no appreciable difference between levels of proteins, carbohydrates, fats, fatty acids, minerals and vitamins in the regular and GE salmons, Altier said. Because there is no difference in the meats, current FDA guidelines would prevent the agency from requiring AquAdvantage to be labeled as GE.
“My personal opinion is, I do think people should be allowed to know that. People make decisions about eating food for all kinds of reasons – whether it's grown locally, whether it's organic, whether even if it's made in the United States. I would have no problem eating a genetically engineered food if it were the same, but I think a lot of people would," Altier said.
Since the FDA could not possibly test the GE salmon for all possible allergens, it plans to monitor the product using the adverse drug reaction reporting system that has long been in place for doctors to inform the FDA of unexpected symptoms of new drugs.
Although this has been successful, Altier foresees complications when it is applied to GE salmon. “If you go out and eat salmon, it’s unlikely that you’re going to associate any allergic reaction with that,” Altier said, particularly if the salmon is not labeled.
The committee also examined the potential effect on wild populations of salmon if they were contaminated with GE salmon. AquAdvantage is more aggressive in getting food, but studies have also shown that they are slower swimmers and greater risk-takers, making them more vulnerable to predators.
Between its facilities in Canada and Panama, Aqua Bounty has devised “extremely elaborate plans for containment,” Altier said. The facility in Canada contains the company’s female brood stock, from which eggs are extracted and made sterile by placing them under high pressure to make them triploid.
This sterilization process has been demonstrated to be around 99 percent effective; AquAdvantage agreed to maintain a minimum of 95 percent sterilization through this process. The eggs are then taken to the highlands of Panama and hatched in an enclosed facility with multiple redundant security features.
Even if there were a salmon “jailbreak” in Panama, Altier hypothesizes, the warm temperatures of the river that serves as the facility’s water source would not support the salmon’s food source, and as the salmon moves down the river, the temperatures would become too high for it to survive. Lastly, any salmon that did survive would be blocked by a hydroelectric dam.
Even though Aqua Bounty appears to have covered all of its bases at the facility in Panama, the facility in Canada still worries Altier because it is next to the ocean, and fertile female salmon would be highly valuable and susceptible to thievery. For this reason, Altier proposes that the GE salmon be treated as “a controlled substance, like a drug that has high abuse potential.” That way, the facility would be monitored with the same level of scrutiny applied to drug manufacturing plants.
As for whether or not the genetic change poses an inherent risk for the fish, Altier and the Committee found the evidence to be inconclusive because they found fault with the research methods Aqua Bounty used to compare deformities in regular and GE fish.
In one study, the total sample size was 120 fish, but the sample sizes for the different test groups were only three or six fish. The triploid female GE salmon test group seeking FDA approval contained six fish. “It only takes an educated scientist to know that that’s a problem,” Altier said.
To run these studies, Aqua Bounty raises both regular and GE fish. Before determining candidates for the study, however, the company uses a culling process to remove abnormal fish – ones that appear sick, small or deformed. While this is an understandable practice for a company raising fish for market, it was unacceptable to the Committee. The purpose of the study – to compare deformities in regular and GE fish – cannot be achieved if the fish are not allowed to grow and potentially develop deformities.
Altier and the Committee continue the draft process, preparing their recommendations about the approval of the GE salmon. Their primary suggestions are for Aqua Bounty to complete new studies on how the genetic change affects the fish using larger samples sizes for all test groups and forgoing the culling process.