WASHINGTON - March 22, 2011 - (Saving Seafood) With 60 scientists working in 15 labs around the nation, the little known U.S.D.A. Agriculture Research Service (ARS) is working to find alternatives to wild caught menhaden-based fish oil and ensure more efficient use of pelagic species-based feed, according its national program leader for aquaculture research, Jeff Silverstein. 

But while strides are being made, he told Saving Seafood that there remains no economically viable or fully realized alternative to fish oil to ensure that farm-raised fish contain the omega-3 fatty acids that benefit human health.

"What is really integral is the long-chain Omega-3 fatty acids which is not produced by fish but in the things fish eat," said Silverstein, a chemist by training. "The best source is (fish) oil."

Despite the ongoing research, there is currently no plant-based replacement to ensure farm-raised fish contain the proper levels of bad cholesterol lowering fatty acids.  In addition, the alternative oils being tested are still prohibitively expensive for regular use. But this does not mean that ARS scientists and their counterparts in industry are not working on alternatives that could become potentially viable in the future.

While ARS is heavily involved in researching alternative feeds for farm-raised fish and has historically mostly focused on protein alternatives for aquaculture use, Silverstein said more attention is starting to be directed toward lipid and oil alternatives to pelagic fish. ARS is conducting feeding studies with algae-based oil and there is commercial work ongoing in that area as well. In addition, some private companies are examining the use of plant-based stearidonic acids as sources of omega-3 for fish.

"There is a lot of work in some of the grain industries to make oils that have a higher Omega 3 content utilizing their naturally occurring medium-chain variants or breeding long-chain fatty acids into grain," said Silverstein.

As such work continues, ARS is attempting to take advantage of the fact that the requirement of fatty acids for good human health is lower than what is typically found in commercial caught fish by utilizing phased feeding techniques. This involves introducing fish oil later in their raising and at smaller quantities as a means to try and use less fish oil in the face of spiking demand for the product. 

Citing projections from the United Nations' Food and Agriculture Organization, Silverstein argued that more efficient use of fish oil is needed as the demand for fish oil continues to rise with demand for farm-raised fish. He noted 90 percent to 95 percent of the fish oil produced worldwide is now used in aquaculture compared to 65 percent of the total commercial fishmeal produced.  

"There is work being done at ARS to basically extend the supply of fish oil," said Silverstein. "We have to reduce the amount of fish oil included in the diet for health until harvest size."

With a 2010 budget of $37.8 million for aquaculture research on a wide variety of species and into reproduction, health, genetics, nutrition and diets, as well as production systems, Silverstein stressed that the agency is not working to place the wild caught and aquaculture industries at loggerheads. He said that ARS could help both to complement each other further in the same manner that Chesapeake Bay oystermen are currently working with oyster farmers to replenish stocks. He cited ARS research into the recovery of flesh and oil from commercial fish frames and viscera as an example of the sort of opportunities available for cooperation.

"There is a lot of opportunity for benefits to both (sectors)," said Silverstein. "I don't think they are naturally at odds."