Researchers found that 80 per cent of marine proteins in conventional feed can be substituted with vegetable ingredients. (Photo: Aquamax/FIS)
Vegetables can replace much of fish ingredients in feed
Tuesday, February 15, 2011, 03:30 (GMT + 9)
The AquaMax international project has determined that vegetable ingredients can replace a large portion of the fish proteins and fish oil used in farmed salmon and salmon trout feeds without sacrificing the products’ health benefits. The project is a collaboration between 33 partners from 14 countries and was headed by the National Institute of Nutrition and Seafood Research (NIFES).
The researchers found that 70 per cent of the fish oil and 80 per cent of the marine proteins in conventional feed can be substituted with vegetable ingredients without harming fish health.
“We know we risk losing some of the beneficial marine omega-3 fatty acids in fish fat by altering the feed composition,” noted Project Coordinator Øyvind Lie, director of NIFES. “Compared to vegetable sources, however, those same marine ingredients may contain more pollutants such as dioxins, PCBs and brominated flame retardants.”
“The risk of ingesting contaminants must be weighed against the health benefits of eating seafood rich in the marine omega-3 fatty acids EPA and DHA,” pointed out Lie. “Pregnant women and the children they are carrying are most vulnerable to pollutants such as dioxins – yet they also have the greatest requirement for the nutrients in fish.”
For the experiment, researchers raised salmon on a customised feed whose large proportions of marine ingredients were replaced with vegetable meal.
The fish fillets were eaten by 62 pregnant women twice a week, from Week 21 of their pregnancy until delivery, and the babies were observed during their first six months. The control group of 62 pregnant women consumed the same amount of fish they normally did.
“In the group that ate the test salmon fillets, omega-3 levels were elevated in both the mothers and their babies,” Lie said. “This means we can raise salmon on feed with high proportions of vegetable ingredients.”
Although vegetable ingredients used in fish feed do contain pollutants as well, AquaMax’s preliminary results show that most do not appear in the actual fish fillets.
Part of the AquaMax project was also to analyse media coverage and interview focus groups to get an idea of public opinion and understanding on eating fish fed vegetable ingredients.
“Public opinion is highly relevant to the issue; unfortunately, the negative perceptions outnumber the positive,” Lie continued.
“Norwegians tend to trust that the authorities will implement proper regulation of this more than people in many other countries,” he said. “And in several countries people were not even aware that salmon is farmed.”
The project was integrated into the European Union (EU) Sixth Framework Programme and included China, India and Norway. The project cost EUR 15 million and launched in March 2006.
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By Natalia Real