The outbreak of mad cow disease in the 1980s and 1990s was linked to processed animal proteins from cattle carcasses. As a result, all kinds of processed animal protein, including those from fish, pork and poultry, were prohibited in feed production for animals that are used for food production. The ban was implemented in Norway through the EEA Agreement.
After careful risk assessments, a change of EU rules in 2013 made it legal to use processed materials from pigs and poultry as a source of protein in feed for farmed salmon. As raw materials from pigs is controversial in some countries, Norwegian fish feed manufacturers informed the Norwegian Food Safety Authority (the FSA) that they do not use ingredients derived from pigs in fish feed production, and that the FSA will be informed if this changes.