AquAdvantage salmon

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AquAdvantage salmon is the trade name for a genetically modified Atlantic salmon developed by AquaBounty Technologies. The AquAdvantage salmon has been modified by the addition of a growth hormone regulating gene from a Pacific Chinook salmon and a promoter from an ocean pout to the Atlantic's 40,000 genes. These genes enable it to grow year-round instead of only during spring and summer. The purpose of the modifications is to increase the speed at which the fish grows, without affecting its ultimate size or other qualities, though competing commercial conventional salmon growers have publicly challenged the purported fast growth rates of AquaBounty's salmon.[1] The fish grows to market size in 16 to 18 months rather than three years.[2] The latter figure refers to varieties whose growth rate has already been improved by 2:1 as a result of traditional selective breeding.

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Aquaculture [edit]

Main article: Aquaculture

Commercial aquaculture is the most rapidly growing segment of the agricultural industry, accounting for more than $60B sales in 2003. While land-based agriculture is increasing between 2% to 3% per year, aquaculture has been growing at an average rate of approximately 9% per year since 1970. The UN expects the consumption of farmed fish to outpace global beef consumption by nearly 10% within five years, according to the UN.[3] As of 2007, Salmon aquaculture produced approximately 69% of world salmon output, and over 80% of Atlantic salmon.

Genetic modification occurs when incorporated gene construct opAFP-GHc2 is transferred into the Atlantic salmon (Salmo salar) and gene construct OnMTGH1 is transferred into the Coho salmon (Oncorhynchus kisutch)[4][5] These transferred genes allow the genetically modified fish to achieve accelerated growth rates, which confer longer survival and reproductive success.[6]

Production [edit]

AquaAdvantage has created a 100-ton/year aquaculture facility in landlocked highlands in Panama, compared to the current 230,000 ton output of farmed Atlantic salmon. Whole Foods has announced that it will not sell AquaAdvantage salmon.[7]

Concerns [edit]

Aquaculture that uses naturally occurring salmon, mostly Atlantic salmon, cultivates the fish in net pens. In North America, this occurs mostly in coastal waters along Washington State, British Columbia and Maine. However, the application for FDA approval of AquAdvantage salmon requires land-based tank cultivation and there are no sea-based pens under discussion. [8]

Genetically modified salmon have raised concerns over the environmental impact they could have if they were to be released into the wild. Currently, no genetically modified salmon have been introduced into the wild. Modeled invasion scenarios in semi-natural environments suggest that genetically modified salmon would have the ability to outcompete wild-type salmon.[9][10][11][12] However, the researcher who developed the "Trojan gene" hypothesis frequently cited by critics of this salmon has discounted this scenario and describes this as an "urban myth". [13]

Wild-Type Atlantic Salmon (Salmo salar).
Wild-Type Atlanta Salmon (Salmo salar).

Survival in new habitats [edit]

Genetically modified fish can learn to feed on new prey, regain a feeding pattern, and switch to different types of food after leaving hatchery environments.[14] These adaptations could pose a risk if genetically modified salmon were to be released into the wild.[14]

Genetically modified salmon can potentially survive twice as long as wild-type salmon.[9] The ability of genetically modified salmon to grow faster does not mean they are preferentially preyed upon, and this leads to increased survival.[9] In a competition scenario, such as a release of genetically modified fish from a salmon farm into the wild, the genetically modified salmon could initially outcompete wild-type salmon for food. This success would allow the genetically modified salmon's greater survival.[9][14]

Rate of growth [edit]

Genetically modified fish have the potential to feed more efficiently than wild-type salmon.[6] This leads to an accelerated growth rate during their first year after birth. These fish have the capability to grow eleven times faster than wild-type salmon. This characteristic allows genetically modified salmon to achieve maturation more rapidly and gives them the ability to reproduce in a time span of less than two years.[6][9] With this accelerated maturity, there is a risk that genetically modified salmon can reproduce at a much faster rate than wild-type salmon.[6]

Smoltification [edit]

Smoltification is the process of salmon adapting from freshwater to marine water. Concerns have been raised around the genetically modified salmon’s ability to potentially achieve smoltification in only one year.[10] This could allow genetically modified fish to reach freshwater quicker. The ability to reach freshwater first could allow genetically modified salmon to be in the presence of more food with less competition from the wild-type salmon.[10]

Potential benefits [edit]

Under simulated models, both prococial parr and anadromous genetically modified male salmon lack reproductive success and have a reduced number of offspring survivals. Additionally, they lack in swimming capabilities as compared to wild-type salmon.[6][10][11][15] The genetically modified salmon expel more energy when swimming than wild-type salmon. This is most likely due to the type of muscle fibers. The genetically modified fish’s muscle fibers are smaller in diameter than wild-type salmon. The force a specific muscle can generate is proportional to the diameter of the muscle, and with a smaller muscle diameter than wild-type salmon, they produce less force than their wild type counterparts.[15]

Genetically modified salmon’s lack of fertilization success can be attributed to nest fidelity, quivering frequency, and spawn participation.[10] Under simulated competition environments, 94% of siring occurred by wild-type salmon, while only 5.4% was attributed to genetically modified salmon.[6] This advantage for wild-type salmon allows the possibility for more than twice as many wild-type offspring to be produced.[6] Other characteristics that could cause wild-type males to be chosen more frequently could be the lack of growth of the kype, the hooked jaw of a male, and red coloration on anadromous males, which shows sexual maturity to females.

Using in vitro analysis, genetically modified salmon's ejaculate was much less concentrated, had a lower sperm count, and decreased sperm velocity, which can decrease the genetically modified salmon’s fertilization success.[6]

Genetic fitness [edit]

Genetically modified salmon can have a higher risk of acquiring disease.[6][10][11]

Potential solutions [edit]

The fish's developer proposes to address these concerns by cultivating only sterile females at inland farms. They claim escapees could not reproduce, either natively or by interbreeding with wild stocks, because they are all triploid, with three sets of chromosomes.[16] They plan to provide farmers with eggs rather than fish.[2] As an extra precautionary measure, it has been suggested that the genetically modified fish only be raised in land-based facilities (as opposed to aquatic, since there has been a history of escapes in such pens).[17]

FDA review [edit]

The Food and Drug Administration (FDA) has an ongoing review of an application by AquaBounty Technologies to allow the AquAdvantage salmon as the first genetically modified animal into the United States food supply. The developer submitted its first data set to the FDA in 1996 and has raised 10 generations of the fish.[18]

In September 2010, an FDA advisory panel indicated that the fish is "highly unlikely to cause any significant effects on the environment" and that it is "as safe as food from conventional Atlantic salmon"[19][20] Kathleen Jones of the FDA's Center for Veterinary Medicine said:

“ In conclusion, all of the data and information we reviewed ... really drive us to the conclusion that AquAdvantage salmon is Atlantic salmon, and food from AquAdvantage salmon is as safe as food from other Atlantic salmon.[21] ”

However the FDA advisory panel also concluded that more research was necessary.[22]

In October 2010, 39 lawmakers wrote to the FDA requesting that it reject the application. Other groups have requested that the fish carry a label identifying its transgenic origin.[20] Concerns included alleged flaws in sterilization, isolation and excessive antibiotic use.[18] In 2012, the major shareholder of AquaBounty Technologies said that he doubted that approval would be granted for the AquAdvantage salmon in a US election year.[23]

On 25 December 2012, the FDA published a draft Environmental assessment for Aquadvantage salmon.[24] The FDA also published a preliminary Finding of No Significant Impact.[25] There was to be a 60 day period for the public to comment before the FDA reviewed Aquadvantage salmon again.[26][27]

As of May 2013, the public comment period officially ended. The FDA is now scheduled to finalize its assessment.[7]

See also [edit]

Notes [edit]

  1. ^ Salmobreed 2011.
  2. ^ a b Blumenthal 2010
  3. ^ Doward 2010
  4. ^ Higgs et al. 2009, pp. 127-137
  5. ^ Raven et al. 2008, pp. 26-37
  6. ^ a b c d e f g h i Fitzpatrick et al. 2011, pp. 185-191
  7. ^ a b Ledford 2013.
  8. ^ Interview with Ron Stotish at BIO
  9. ^ a b c d e Sundström & Devlin 2011, pp. 447-460
  10. ^ a b c d e f Moreau, Conway & Fleming 2011, pp. 736–748
  11. ^ a b c Wei & ZuoYan 2010, pp. 401-408
  12. ^ Ahrens 2011, pp. 583-597
  13. ^ Foes of GE salmon raise specter of 'Trojan gene' effect
  14. ^ a b c Sundström et al. 2009, pp. 762-769
  15. ^ a b Lee, Devlin & Farrell 2003, pp. 753-766
  16. ^ Ron 2010
  17. ^ % (2013-02-11). "Is Genetically Modified Salmon Safe? : Discovery News : Discovery News". News.discovery.com. Retrieved 2013-05-08. 
  18. ^ a b Naik 2010
  19. ^ FDA 2010.
  20. ^ a b Mundy & Tomson 2010
  21. ^ Carollo 2010
  22. ^ Hedlund 2012
  23. ^ Pollack 2012
  24. ^ FDA December 2012.
  25. ^ FDA May 2012.
  26. ^ Federal Register 2012.
  27. ^ Reardon 2012

References [edit]

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