Fish oil is fat from fish parts or industrial fish (i.e. fish that is not intended for human consumption). Fish oil has a high content of the omega-3 fatty acids EPA and DHA. From one kilogram of industrial fish, around 80 grams of fish oil can be produced.
Vegetable ingredients in fish feed are derived from plants like soy, sunflowers, rapeseed, corn, broad beans and wheat. The vegetable products are a source of protein, carbohydrates and fat. Some feed products contain 0.5 percent palm oil as a binding agent.
Fishmeal is produced by fish heads and other parts that are not used for human consumption. Fishmeal contains proteins and minerals. From one kilogram of industrial fish, around 230 grams of dry fishmeal can be produced.
Fish protein concentrate is produced by scrapings from the consumer fishing industry.
Fish feed also contains vitamins, minerals, pigments and amino acids. The antioxidant astaxanthin is added to salmon feed to boost the fish's immune system and to protect their tissue. It is also a source of vitamin A. Astaxanthin is the substance that gives salmon its red colour. Wild salmon get astaxanthin by eating crustaceans.
Does salmon feed contain toxins?
Norwegian fish does not contain high levels of heavy metals or contaminants. The research institute NIFES was commissioned by the Norwegian Food Safety Authority to investigate if Norwegian fish feed contains high levels of illegal substances. The report from 2015 concluded that the regulatory thresholds are rarely exceeded. The results showed that so called complete feed and feed ingredients do not exceed the limits for heavy metals and organic pollutants. The exception is one complete feed, which contains residues of the pesticide hexachlorobenzene (HCB) over the limit. The limit for HCB is 10 micrograms per kilogram, and the complete feed was found to have 11 micrograms per kilogram. According to NIFES, the level is still so low that it does not pose a risk to food safety.
As fish feed increasingly consists of vegetable ingredients, NIFES has expanded the list of monitored pesticides. The samples from 2014 showed that the levels of pesticides are generally low.
Program for monitoring fish feed 2015 (samples collected in 2014): http://nifes.no/wp-content/uploads/2015/11/forrapport2015.pdf (in Norwegian only)