Use of Terrestrial Based Lipids in Aquaculture Feeds and the Effects on Flesh Organohalogen and Fatty Acid Concentrations in Farmed Atlantic Salmon

Abstract

Consumption of salmon, wild or farmed, has been encouraged by many scientists and by national and international health organizations due to the potential health benefits associated with their high contents of omega-3 (n-3) highly unsaturated fatty acids (n-3 HUFAs). In 2004, there was increased public concern regarding the safety of farmed Atlantic salmon following the publication of several studies that indicated higher levels of organohalogens in their flesh relative to those noted in the flesh of wild Pacific salmon. Farmed salmon obtain most of these contaminants from the consumption of marine fish oil (MFO) present in salmon feed. In both a laboratory feeding trial and an on-farm field study, partial replacement of MFO in aquaculture feeds with economical and abundant lipids of terrestrial origin resulted in farmed Atlantic salmon with reduced flesh polychlorinated biphenyl and polychlorinated dibenzodioxin and furan concentrations. Flesh levels of n-3 HUFAs (g/(100 g serving)) were lower in farmed Atlantic salmon fed diets with alternative lipids relative to farmed salmon fed more traditional MFO-based diets. However, the former salmon were found to have higher flesh levels of n-3 HUFAs and also similar or lower flesh levels of organic contaminants than some species of market-size wild Pacific salmon. These findings showthat consumption of either farmed Atlantic salmon or wild Pacific salmon can meet recommended weekly n-3 HUFA levels with minimal concurrent intake of flesh organohalogens.

Fish Nutrition and Current Issues in Aquaculture: The Balance in Providing Safe and Nutritious Seafood, in an Environmentally Sustainable Manner

“…Studies have shown that using plant oils to replace FO for most of the production cycle show large reductions in flesh POPs in salmon; thereby providing a low contaminant product for human consumption [75,76]. Interestingly, Atlantic salmon fed a diet that replaced 75% FO with flaxseed oil showed 61% lower levels of POPs in the flesh compared with fish fed diets with 100% FO, without compromising growth performance [77]. Farrell et al [78] concluded that plant oils in salmon feeds considerably lower contaminant levels in farmed salmon without reducing the human health benefits and compromising production efficiency.…”

Contamination of finfish with persistent organic pollutants and metals

“…Estimated fi sh oil inclusion in salmon feeds in 2010 was 12-15%, while in 2020 it is predicted that 6% fi sh oil will be used (Tacon and Metian 2008). The fi sh oils are replaced with plant oils, or in some cases also animal oils (Drew et al 2007b;Miller et al 2008), and replacement of fi sh oil with these alternative ingredients causes a reduction of POP loads in the farmed fi sh (Bell et al 2005;Berntssen et al 2005;2010a;2010b;Drew et al 2007b;Friesen et al 2008;Nacher-Mestre et al 2009) ( Table 19.7 ).…”

Toward Improved Public Confidence in Farmed Fish Quality: A Canadian Perspective on the Consequences of Diet Selection

“…Friesen et al (2008) similarly evaluated the cost‐effectiveness of utilizing different blends of either cold‐pressed flaxseed oil or poultry fat as replacements for as much as 75% of the supplemental anchovy oil in a premium quality grower diet for sablefish. Sablefish are a marine species with a high genetic propensity to accumulate lipids in their flesh and a promising new aquaculture species.…”