Influence of terrestrial lipid and protein sources and activated carbon‐treated fish oil on levels of persistent organic pollutants and fatty acids in the flesh of Atlantic salmon

Reductions in flesh contaminant concentrations were evaluated in a 36-week feeding trial examining several dietary techniques. Atlantic salmon were fed one of seven dietary treatments for 24 weeks. These diets included a fishmeal, fish oil control diet, an industry control diet, three diets that examined a 75% replacement level of anchovy oil (AO) with flaxseed oil, canola oil and poultry fat, and two diets formulated to be low in contaminants formulated with canola oil, activated carbon-treated anchovy oil and canola protein concentrate or soy protein concentrate. Following this initial 24-week feeding interval, a 12-week finishing diet was utilized to restore the levels of omega-3 highly unsaturated fatty acids (n-3 HUFAs). The salmon had marked reductions in their flesh concentrations of total polychlorinated biphenyls (PCBs), dioxin-like PCBs and total toxic equivalents by the end of the grow-out phase, but also exhibited significant depressions in their flesh concentrations of n-3 HUFAs relative to 100AO-fed fish. The 12-week finishing diet period was effective in partially re-instating omega-3 levels to those present in the flesh lipids of fish fed 100AO while concurrently maintaining lower flesh contaminant concentrations.