January 20, 2004

SIUC Country Column Canola oil may offer multiple benefits to fish farmers

by K.C. Jaehnig

CARBONDALE, Ill. -- Canola oil could help fish farmers raise a better fish.

Research has shown that eating foods containing Omega-3 long-chain fatty acids can protect the heart, kidneys, immune system and brain, so scientists at Southern Illinois University Carbondale have been working to develop an inexpensive way of boosting levels of these polyunsaturated fats in the flesh of hybrid striped bass.

Adding fish oil to what the fish themselves eat could do the job, but fish oil doesn't come cheap.

"We found that we can thin the fish oil with 50 percent canola oil and not adversely affect the Omega-3 levels," said Christopher C. Kohler, director of SIUC's Fisheries and Illinois Aquaculture Center.

"It's as good as using 100 percent fish oil."

Using the canola-fish oil mix could not only help farmers save a little money on feed but could aid the environment, too. Most fish oil comes from menhaden. Members of the herring family, these silvery fish feed near the bottom of the food chain and serve as dinner for larger species.

"Aquaculture is sometimes criticized for using too much fish oil and fish meal because of worries about depleting fish stocks," Kohler said.

"The more we can use renewable resources, such as canola, the better it is for the industry as a whole. It's also good for the farmers who grow canola, as they would become one of the major suppliers."

SIUC researchers will next try using various combinations of feed grain to reduce or cut out altogether the feed's fish meal component.

"Fish meal, like fish oil, is very expensive," Kohler said. "Availability -- and therefore price -- goes up and down depending on what's happening with the weather."

While the researchers have focused mainly on hybrid striped bass in this project, they are also looking at oil-enhanced diets for catfish -- for a different reason.

"The human immune system seems to get a boost from Omega-3 fatty acids, so we're trying to see if that holds true in catfish," Kohler said.

"Are they more robust than fish that don't get this? If so, there may be good reason to have it in their diets even if they don't get much of a boost in their own Omega-3 levels."

A $600,000 grant from the National Science Foundation is paying for the project, which is providing a wealth of experience for graduate students. Emily J. Wonnacott ofBelleville (36 Kingston Drive), for example, wrote her master's thesis on her work with the canola-fish oil mix.

"Almost all of my students are doing research on Omega-3 now," Kohler said. "The grant has allowed us to approach this area from many different angles."