General
1. What is different about AquAdvantage Salmon?
AquAdvantage Salmon has been genetically engineered to grow to market size more rapidly than its non-GE Atlantic salmon counterpart. It does so because it contains an rDNA construct that is composed of the growth hormone gene from Chinook salmon under the control of a promoter (a sequence of DNA that turns on the expression of a gene) from ocean pout (another type of fish). This allows the salmon to grow to market size faster.
2. What is the source of the data in the application?
For its review, FDA relied on the data provided in the application, as well as other sources of data and information, including articles from peer-reviewed journals, taking care to ensure the most relevant data and information received the most weight in the agency’s decision-making process.
The data in the application are provided by the company, because the burden of proof is on the sponsor, or company, to demonstrate safety and to validate the claim that is being made. As part of the review process, whenever the FDA had additional questions, the sponsor provided additional data or information.
3. What did the FDA consider to be the potential environmental impacts?
In compliance with requirements of the National Environmental Policy Act (NEPA), the FDA evaluated the potential effects on the environment of the United States from an approval of the application related to AquAdvantage Salmon. Specifically, the FDA asked the following four questions:
- What is the likelihood that AquAdvantage Salmon will escape the conditions of confinement
- What is the likelihood that AquAdvantage Salmon will survive and disperse if they escape the conditions of confinement
- What is the likelihood that AquAdvantage Salmon will reproduce and establish if they escape the conditions of confinement
- What are the likely consequences to, or effects on, the environment of the United States should AquAdvantage Salmon escape the conditions of confinement
Based on the multiple forms of physical and biological containment proposed by AquaBounty Technologies in the application, the FDA found that an approval of the application related to AquAdvantage Salmon would not cause a significant impact on the environment of the United States. This finding is based on the extremely low likelihood that AquAdvantage Salmon could escape into the environs surrounding the PEI and Panama facilities and survive in an ocean or waterway and interbreed with wild Atlantic salmon due, in part, to the physical and biological containment measures specified in the approved application, and thus affect the environment of the United States. Based on the agency’s conclusion from the final Environmental Assessment, the agency issued a final Finding of No Significant Impact (FONSI).
4. What kinds of physical containment does the approved application specify will be at the two facilities at which AquAdvantage Salmon will be raised?
The facilities in Canada and Panama have a series of multiple and redundant levels of physical barriers to prevent eggs and fish from escaping. The facilities use land-based tanks, not ocean net pens, which are not allowed under the approved application. The first level of barriers (Primary Containment) includes items such as metal screens on tank bottoms, stand pipes, and incubator trays to prevent the escape of eggs and fish during hatching or rearing. Tanks also have covers, nets, jump fences, and screened overflow tanks to prevent escape over the sides of the tanks or incubators. Tank netting also keeps predators such as birds from entering the fish tanks at the outdoor facilities in Panama. All tank drains and stand pipes have covers or sleeves permanently attached to them. In order to prevent eggs or small fish from passing through the pipes or plumbing there is a closed septic system and additional screens and chlorine pucks are used to kill any escaped fish in the main drain area.
Several additional sets of barriers, also in series (Secondary, Tertiary, and sometimes Quaternary Containment), add increased physical security to the Primary Containment measures described above. These barriers are designed to prevent fish from entering the drainage system or sedimentation pools and the local river (in the case of the Panama facility) and include floor drain covers, barrier screens inside the drains, drum and sock filters, and a series of sedimentation ponds with outlet filters.
To augment physical containment, strict security measures and equipment are in place at both facilities. This includes locked gates for entry and exit to the properties, the presence of guard dogs, perimeter fences with barbed wire, and monitoring systems.
Graphics describing these containment measures can be found at Figures 6 and 7 of the EA.
5. Why is FDA not requiring mandatory labeling of food from GE Atlantic salmon?
The FDA has determined that food from AquAdvantage Salmon is as safe and nutritious as that from non-GE Atlantic salmon. The Federal Food, Drug, and Cosmetic Act (FD&C Act) provides statutory authority for mandatory labeling of food if there is material information that must be disclosed within the meaning of sections 403(a) and 201(n) of the FD&C Act. Because the data and information evaluated show that AquAdvantage Salmon is not materially different from other Atlantic salmon, the FDA has determined that no additional labeling of food from AquAdvantage Salmon is required.
The FDA requires additional labeling in cases where it is necessary to ensure that the labeling is not false or misleading. For example, if a material difference, i.e., changes in the nutritional profile, cooking qualities, etc. was found to exist between a given product and its conventional counterpart additional labeling describing the material difference would be required. FDA has required a statement on low-fat margarine indicating that it is not suitable for frying.
As with all foods, a company may include voluntary information in labeling, provided the information is truthful and not misleading.
The FDA recognizes that some consumers are interested in knowing whether a food is derived from GE Atlantic salmon, so the agency is also publishing a draft guidance for food manufacturers who wish to voluntarily label their food products or ingredients derived from salmon as either containing or not containing GE Atlantic salmon. You can see the draft guidance here: http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/ucm469802.htm.
6. How will the FDA monitor AquAdvantage Salmon now that it has been approved?
All FDA-approved new animal drugs have post-market surveillance programs. For this application, the approval letter describes record-keeping and reporting requirements, including demonstrating the presence and stability of the AquAdvantage rDNA construct, ensuring that the triploidy process (a method used in finfish and shellfish to prevent their sexual maturation and to make them sterile) is within specifications, reporting of any adverse effects of the rDNA construct on animal health, and reporting of any instances of presumed infectious disease. In addition, the sponsor is required to monitor physical containment, including reporting of any likely or actual breaches of physical containment.
7. Does the agency expect this decision to pave the way for approvals of other genetically engineered animals?
The FDA cannot speculate on whether more producers of genetically engineered animals will submit applications based on this approval and cannot comment on whether other sponsors have already submitted such applications. The agency reviews each application on a case-by-case basis, and its own merits in order to determine whether the product is effective, safe for the animal and, in the case of applications for GE food animals, is safe for humans and animals to eat.
The rigorous review process includes seven elements of evaluation. Companies seeking an approval must provide data to substantiate each element:
- Product definition: a broad statement characterizing the GE animal and the claim being made for the GE animal;
- Molecular characterization of the construct: a description of the rDNA construct and how it is assembled;
- Molecular characterization of the GE animal lineage: a description of the method by which the rDNA construct was introduced into the animal and whether it is stably maintained over time;
- Phenotypic characterization of the GE animal: comprehensive data on the characteristics of the GE animal and its health;
- Durability plan: the sponsor’s plan to demonstrate that the modification will remain the same over time, and continue to have the same effect.
- Environmental and food/feed safety: the assessment of any environmental impacts, and for GE animals intended for food, that food from those GE animals is safe to eat for humans and/or animals;
- Claim validation: a demonstration that the GE animal does fulfill the product definition stated in the beginning of the review process.
The first genetically engineered animal that received FDA approval was a line of genetically engineered goats that produce a recombinant human anti-clotting protein in their milk. The FDA’s Center for Biologics Evaluation and Research also approved that protein (ATryn) as a human biological drug for the prevention of abnormal clotting in people with hereditary antithrombin deficiencies who are having surgery or giving birth.
For more information on the review process, see http://www.fda.gov/AnimalVeterinary/DevelopmentApprovalProcess/GeneticEngineering/ GeneticallyEngineeredAnimals/ucm113605.htm.
8. Are AquAdvantage Salmon more susceptible to disease than non-GE salmon?
No. Scientific data do not support the assertion that AquAdvantage Salmon are any more susceptible to disease than non-GE farm-raised Atlantic salmon under the aquaculture conditions in which they are raised.
9. Why is the FDA approving the AquAdvantage Salmon?
Under the Federal Food, Drug and Cosmetic Act, FDA is required to review applications for safety and effectiveness. Based on a comprehensive analysis of the scientific evidence, the FDA has determined that the AquAdvantage Salmon meets the statutory requirements for safety and effectiveness under the FD&C Act. The fish are safe for humans and animals to eat, the rDNA construct is safe for the animal, and the claim about faster growth made by the sponsor has been confirmed. Because the sponsor has met these and other statutory requirements, the FDA must approve the application.
The FDA has also analyzed the potential environmental impact that an approval of the AquAdvantage Salmon application would have on the U.S. environment and has published its final Environmental Assessment and Finding of No Significant Impact.
10. How are genetically engineered animals regulated?
Genetically engineered animals are regulated under the new animal drug provisions of the Federal Food, Drug, and Cosmetic Act (FD&C Act) because an rDNA construct that is intended to affect the structure or function of the body of the resulting animal meets the definition of a drug. Please see GFI 187 for a detailed description of the kinds of recommended for sponsor to submit, and that the agency will review.
The FDA held a Veterinary Medicine Advisory Committee meeting that addressed the application and a Part 15 hearing that addressed labeling of food from AquAdvantage Salmon, which were both open to the public, released draft environmental documents on the application, and solicited public comment in connection with all of these activities.
11. What is triploidy?
Triploid fish have three sets of chromosomes in the cells of their body instead of the more common two sets (referred to as “diploid”). Triploidy is a method used in certain plants and animals, including finfish and shellfish, to prevent their sexual maturation and thereby make them functionally sterile. In addition to providing a form of biological containment, this can redirect energy to growth instead of to reproductive development. The sponsor has proposed to induce triploidy by a method that is commonly used in commercial aquaculture -- shortly after they are fertilized, the fertilized eggs are put in a pressure chamber (a large stainless steel container resembling a very heavy-walled thermos bottle) and pressure is applied to them.
Containment
1. What is meant by “multiple redundant containment” in the context of AquAdvantage Salmon?
Multiple redundant containment means that there are several independent levels and types of barriers to prevent escape and establishment of salmon populations outside the land-based tanks in which the AquAdvantage Salmon are bred and raised. For example, for physical containment there are multiple screens and filters throughout both facilities. With respect to biological containment, there are two independent but complementary methods: producing only one sex of fish, and making the female fish sterile via triploidy induction (a method used in finfish and shellfish to prevent their sexual maturation and make them sterile). In addition, particularly at the Panama grow-out facility, there are geographical/geophysical containment features, including high river and ocean water temperatures, and other conditions that would not be supportive of salmon survival.
2. What is meant by biological containment?
Biological containment is a term that means limiting the reproductive ability of an animal. We use biological containment when we neuter our pet dogs or cats. More advanced methods of biological containment, or bio-confinement, use methods such as altering the chromosome number of an organism such as triploidy (a method used in finfish and shellfish to prevent their sexual maturation and make them sterile), and making single sex populations to induce sterility and/or prevent gene flow and reproduction in the environment.
3. What is meant by physical containment?
Physical containment refers to mechanical (or chemical) measures or barriers used at a facility to prevent the physical movement or escape of fish from that facility. Physical containment equipment includes screens with very small openings that allow water to flow through, but that will not allow the passage of eggs and fish. The mesh size of the screens range from 0.03 to 0.5 inches in diameter, which is roughly 10 to 100 times narrower than the fish is wide. Examples of these barriers include metal (usually stainless steel) and plastic screens, fine meshes, filters, and grates in the water drainage pipes and sumps that prevent eggs, fry (very small fish that have just hatched from eggs), and larger fish from being able to escape to the outside environment. Physical containment also includes tank covers and nets to prevent fish from being able to jump out of tanks and prevent predators such as birds from being able to remove them. (See EA Figure 6.)
4. What would happen if any of the AquAdvantage Salmon escaped from the Canadian facility? Would the fish survive and impact the environment of the United States?
In the highly unlikely event that any salmon escaped from the facility, the potential for survival would be extremely low. Eggs and young fish would not survive if they escaped because they can only live in fresh water. The location of the facility is near an estuary (a body of water in which fresh and salt water mix and that is “slightly salty”) and the sea itself. Both of these conditions are too salty for young life stages to survive. For an older, larger fish to escape, it would have to make its way past a series of barriers and screens whose openings are very small (0.03 to 0.5 mm), which is roughly 10 to 100 times narrower than the fish is wide (see Figure 6 of the EA). Even then, the fish’s survival would depend on the season of the year because the winters where the facility is located in Prince Edward Island (PEI), Canada, are very cold and the water temperature is sometimes at or even below freezing (this is possible because the water is salty). Even if one of these fish were somehow able to escape, it is extremely unlikely it would survive for long or become established in the local environment. This is because currently there are no native Atlantic salmon in the nearby river system or any of the other rivers in the area, despite intentional stocking attempts over many years, which indicates that conditions are inhospitable for survival.
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本文地址：http://www.wjbb.com/know/1340
原文出处：http://www.fda.gov/AnimalVeterinary/DevelopmentApprovalProcess/GeneticEngineering/GeneticallyEngineeredAnimals/ucm473237.htm
