By Head of Research Robin Ørnsrud
Here in Norway, livestock feeding has taken place since the Neolithic Period. Feeding herring or saithe is not that common, but the feeding of farmed fish has taken place for many decades and gives us a unique opportunity to produce food that is both healthy and safe.
Food scandals can arise as a result of contamination of feed. The 1999 Belgian dioxin scandal and the UK mad cow scandal in 2001 showed that both chemical contaminants and infectious agents can be transferred to consumers via feed . The feed given to food-producing animals is therefore important for food safety, and undesirable incidents in connection with feed production can have a negative impact on the rest of the food chain. That is why strict regulations have been developed that set high hygiene standards and regulate what feed ingredients are permitted. The regulations also set maximum limits for both additives and undesirable substances.
In the infancy of the aquaculture industry, fish feed was mostly made from fish meal and fish oil. These feed ingredients contain background concentrations of environmental contaminants such as dioxins and PCBs. These stable, fat-soluble ubiquitous compounds accumulate in the marine environment. They are therefore found in fatty fish, which is often used in the production of fish oil and fish meal. In recent years, the proportion of fish meal and fish oil in farmed salmon feed has been significantly reduced due to these ingredients becoming less available. Feed ingredients from agriculture, such as rapeseed oil, wheat, soya, peas and maize, now constitute a large proportion of the fish feed and have resulted in significantly lower levels of the environmental contaminants traditionally found in fish meal and fish oil. All feed ingredients can contain undesirable substances, andNIFES monitors undesirable substances and the nutrient content of fish feed and feed ingredients on assignment for the Norwegian Food Safety Authority. The results of the annual feed monitoring show that the levels of marine environmental contaminants in fish feed have decreased. This is also reflected in the muscle tissue of farmed salmon, which contains 70% less dioxins and PCBs in 2014 compared with 2006.
The increased use of vegetable ingredients therefore reduces the levels of the traditional environmental contaminants in fish feed, but the use of new feed ingredients also introduces new undesirable substances, such as e.g. agricultural pesticides. Such pesticide residues have not previously been associated with fish feed, and the current regulations for pesticides are not adapted to fish feed or seafood. More knowledge is needed about how much and which pesticides are found in the feed ingredients, how much is transferred to the edible part of the fish and what effect this has on fish health. A preliminary screening has found that there may be residues of the pesticides chlorpyrifos and pirimiphos-methyl in feed ingredients and the fish feed, but the substances have not been found in the muscle tissue of the salmon eating the feed. It is important to monitor possible current and future pesticide residues in feed ingredients, fish feed and the muscle tissue of the fish. As a research institution providing knowledge support to the public administration, NIFES aims to be one step ahead when it comes to emerging threats in the food chain. Stringent control of risk factors in feed is crucial for the production of safe food!
Printed in the newspaper Fiskeribladet Fiskaren, 03.06.15