November 17th, 2006
Researchers at the Swedish University of Agricultural Sciences (SLU) are testing alternative feeding for farmed salmon and rainbow trout. Farmed fish is normally fed fish products and fish oil, and the omega-3 fatty acids EPA and DHA are important constituents in their food. Alternative feeding is now being tested since fish oil may be in short supply in the future.
The researchers conclude that the fish grows well when the fish oil is replaced with rapeseed oil by 75, 50 and 25 percent. When rapeseed oil is part of the fish's diet the meat will contain the short chain fatty acid ALA and bioactive sterols. A negative aspect is however that the fish contains less of the long chain fatty acids EPA and DHA.
If the fish is allowed to chose what food to eat, it prefers the fish oil before the rapeseed oil.