Lipid Composition and Contaminants in Farmed and Wild Salmon

Abstract

Levels of omega-3 (n-3) and omega-6 (n-6) fatty acids and lipid-adjusted concentrations of polychlorinated biphenyls (PCBs), dioxins, toxaphene, and dieldrin were determined in 459 farmed Atlantic salmon, 135 wild Pacific salmon, and 144 supermarket farmed Atlantic salmon fillets purchased in 16 cities in North America and Europe. These were the same fish previously used for measurement of organohalogen contaminants. Farmed salmon had greater levels of total lipid (average 16.6%) than wild salmon (average 6.4%). The n-3 to n-6 ratio was about 10 in wild salmon and 3-4 in farmed salmon. The supermarket samples were similar to the farmed salmon from the same region. Lipid-adjusted contaminant levels were significantly higher in farmed Atlantic salmon than those in wild Pacific salmon (F = 7.27, P = 0.0089 for toxaphene; F = 15.39, P = 0.0002 for dioxin; F > or = 21.31, P < 0.0001 for dieldrin and PCBs, with df = (1.64) for all). Levels of total lipid were in the range of 30-40% in the fish oil/fish meal that is fed to farmed salmon. Salmon, especially farmed salmon, are a good source of healthy n-3 fatty acids, but they also contain high concentrations of organochlorine compounds such as PCBs, dioxins, and chlorinated pesticides. The presence of these contaminants may reduce the net health benefits derived from the consumption of farmed salmon, despite the presence of the high level of n-3 fatty acids in these fish.

Differences in organochlorine accumulation accompanying life history in the catadromous eel Anguilla japonica and the marine eel Conger myriaster

“…The extreme high lipidosomatic ratios, up to 31% compared to 3-9% of most freshwater species, coupled with its breeding biology make anguillid eel species sensitive to the bioaccumulation of organic contaminants and to their toxicological effects (Corsi et al 2005). Farmed Atlantic salmon had greater levels of total lipid (16.6% on average) than wild Pacific salmon (6.4% on average), which means the farmed salmon contained high concentrations of OCs (Hamilton et al 2005). These results suggest that even in the same species, family and order having similar growth stages, habitats and feeding, OCs accumulation was different depending on the Fig.…”

Negative externalities of food production: discourses on the contested Norwegian aquaculture industry

“…Veterinary science, for example, observes that every time a dense animal population is placed in the same area over a long period of time, pathogens build up (Børresen 1995;Jansen et al 2012;McNeill 1976). Mennerat et al's study (2010) identifying the correlation between aggressive sea lice and sea farming is supported by Jansen et al (2012) and Hamilton et al (2005) who confirm the causal relationship between density of salmon populations and disease. These statements address these findings:…”

Mast cells and multiple sclerosis in females and males

“…Salmon and trout were in fact far too expensive for everyday consumption in these communities. Today the farmed salmon is cheap and easily available, but unfortunately the nutritional value has been questioned due to altered composition of their fatty acids [16][17][18], resulting from modern aqua-cultivation of salmon. As proposed by others [19,12] the epigenetic effect of vitamin-D consumption by the mothers or grandmothers may be highly beneficial for the fetus, and may explain why MS was low in coastal areas since herring, mackerel and cod liver is high in vitamin-D [20].…”