Transgenic plants could make for more nutritious salmon
Although salmon are known to be a good source of healthy omega-3 fatty acids, farmed fish typically contain much less of them than their wild counterparts. Norwegian scientists are working on a solution to that problem, in the form of fish feed made from a genetically-engineered plant.
Among other things, omega-3's such as EPA and DHA are known to reduce the risk of heart disease, boost the neurological development of infants, lessen depression, and reduce the effects of rheumatoid arthritis.
Salmon don't produce significant amounts of the fatty acids on their own, but instead obtain them by eating other fish. In the wild, this isn't a problem. In farms, however, salmon are fed mainly plant-based foods. Fish oil used to be added to these in order to increase their nutritional content, although increased demand for commercial salmon feed has led to a shortage of such oils, boosting their price and reducing their availability – vegetable oil is now often used instead.
According to scientists at the Norwegian University of Science and Technology, this has resulted in farmed salmon having as little as one quarter the amount of omega-3's as they used to. "Before, eating farmed salmon twice a month was sufficient to consume enough omega-3," says Prof. Rolf Erik Olsen. "Now you may need to eat it more like twice a week."
With that in mind, Olsen and colleagues transferred genes from an omega-3-producing algae to camelina plants (Camelina sativa), which caused the plants to produce high amounts of EPA and DHA in their seeds. Oil made from those seeds was subsequently fed to young salmon until they doubled their weight. No health problems were noted in the fish, the meat of which contained EPA and DHA levels similar to those of salmon raised on a much more expensive fish-oil diet.
Once further research has been conducted at Scotland's University of Stirling, it is hoped that the engineered plants could be grown commercially. Camelina, incidentally, is already grown as a source of biofuel.