Tasty Transgenics

Tasty transgenics

Posted by Jennifer Welsh

[Entry posted at 28th July 2010 02:41 PM GMT]

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AquaBounty Technologies made big news when they announced they were getting close to approval for their fast-growing transgenic salmon, but this isn't the only transgenic project with its eyes on our food supply. Several other projects are underway to develop transgenic animals that may eventually make their way into agriculture's mainstream and end up in your grocery aisle. And scientists aren't just interested in bigger animals -- they're also looking at making meat that's more environmentally friendly, and healthier.  A cleaner pig  Enviropigs Image: University of Guelph The stereotype of pigs as dirty animals is being challenged by the University of Guelph's "Enviropig," which, while growing at a normal rate, produces less waste and needs less food. The pig was specifically created to solve the environmental run-off problems of pig farming.  Normal pigs can't digest phytate, which makes up around 50-75 percent of phosphorus present in cereal grains, corn and soybeans -- the pig's main food. This excess phytate comes out in their waste, and they need to be fed additional phosphorus in a digestible form. The Enviropig contains a gene from E. coli called phytase, which encodes an enzyme which metabolizes phytate molecules into readily absorbed phosphate. As a result, it eats less feed and produces less waste, including 30-65 percent less phytate waste, which in turn decreases the chemical contamination of agriculture drainage areas.  "We originally set out to help farmers around the world reduce the environmental impact of raising pigs," said Richard Moccia.  The University owns the rights to the pig, and has been in the process of getting approval from both the U.S. Food and Drug Administration and Health Canada since 2007. Health Canada is satisfied that the Enviropig does what it says it does, and will not harm the environment, but the university is still in the process of assembling documentation of the safety of Enviropigs for human consumption. Approval, if it happens, is at least a few years off, said Moccia.  Fat-friendly meats  Omega-3 piglets Image: Jing Kang, Harvard Medical School Omega-3 fatty acids are trendy, and for good reason -- their consumption is linked to better cardiovascular health and lower risks of diabetes and cancer. But they can be hard to come by in a land-locked diet, since they are only produced by plants and lower life forms, such as algae in the ocean. Farm animals fed a diet consisting mainly of grain, soybeans and corn don't consume much omega-3, and naturally contain only omega-6 fatty acids, which don't have the same health benefits.  "We realize the huge imbalance in omega-6 to omega-3 in the human diet," said Jing Kang at Harvard Medical School. "We want to decrease the omega-6 and increase the omega-3."  Kang has inserted the fat-1 gene from C. elegans into pigs, which allows them to convert the omega-6 fats found in their normal feed into omega-3s.  Kang is currently working on other animals, such as chicken and fish, and also vegetables which don't usually contain omega-3, like tomatoes. Kang is looking for a company to commercialize the technology, and to help with the time and expense of dealing with regulatory issues, and couldn't offer a projection of when the food could hit the market.  A fatter salmon  An AquaAdvantage Salmon and  its non-transgenic sibling AquaBounty Technologies The AquaAdvantage salmon grows twice as fast as regular salmon, reaching full growth in captivity by 200 days, instead of 400. The salmon grows faster because researchers inserted the gene for a growth hormone from the Chinook salmon (which grows much faster) into Atlantic salmon eggs.  In theory, the AquaAdvantage salmon could provide relief to the ongoing pressure on natural fisheries, and, because it is grown in pens built on land, cut down on the environmental impact of shipping fish from the coasts.  The AquaAdvantage salmon is the transgenic animal closest to getting FDA approval for human consumption, having passed five sections of the FDA's seven-part application. The company has submitted all the remaining required information, and is expecting a decision soon.  AquaBounty is also working on implementing the same growth-hormone technology in tilapia, shrimp and other important aquacultures, said Val Giddings, a consultant who worked for the food and agriculture division of the Biotechnology Industry Organization for a decade and has worked with AquaBounty.  Big fish, mutant cows, flu-resistant birds  - Terry Bradley, an aquaculture researcher at the University of Rhode Island, has produced rainbow trout with six-pack "abs" and hulk-like shoulders by blocking the fish's myostatin gene, which inhibits muscle differentiation and growth.  - BioDak, LLC is producing cows that are resistant to bovine spongiform encephalopathy (the prion-based "mad cow disease"), as well as cows that don't produce antibodies, for research purposes.  - Laurence Tiley from Cambridge Veterinary School is working with Helen Sang of the Roslin Institute to produce chickens that are immune to the flu virus, hopefully decreasing the impact of avian flu on chicken stocks. Their technique includes introducing the antiviral protein Mx into the chickens and inserting small RNAs to disrupt the flu virus.

Read more: Tasty transgenics - The Scientist - Magazine of the Life Sciences http://www.the-scientist.com/blog/display/57577/#ixzz1ryaUVLAf


Available in: http://classic.the-scientist.com/blog/display/57577/

Entry author: Astrid Espinosa Sánchez.