Reduction of persistent and semi-persistent organic pollutants in fillets of farmed European seabass (Dicentrarchus labrax) fed low fish oil diets

Abstract

Traditionally, a major part of aquaculture technology requires fish oil (FO) and fish meal (FM) to produce the aquafeed for farmed species. FO is the main source of persistent organic pollutants (POPs) in fish feed. In recent years, the use of vegetable-origin ingredients in fish feeds has been increasingly studied as an alternative to reduce the levels of these lipophilic pollutants in farmed species. The aim of this study was to evaluate the effect of the use of dietary vegetable oils in the farming of European sea bass (Dicentrarchus labrax) on the contents in persistent - polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) - and semi persistent pollutants - polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (BDEs) - of their edible parts. A total of 60 seabass muscle pools were obtained from fish farmed employing six experimental diets, which contained different percentages of FO (6 vs. 3%) and FM (20%, 10% and 5%). We did not observe differences in the contamination level of seabass muscle in relation to the percentage of FM in their diet. However, the fish farmed using feed which had lower levels of FO (3%) showed significantly lower muscle levels of ΣPCBs and carcinogenic PAHs (Σc-PAHs), with a reduction of 25.6% and 95.11% (respectively), as compared with those fished raised with feed with higher levels of FO (6%). Also much lower levels were found in OCPs such as sum of DDTs (30.88% of reduction), sum of chlordanes (42.85% of reduction), and sum of BDEs (48.16% of reduction) in those seabass fed with a lower percentage of FO. The results of this study indicate that the use of alternative feed ingredients that allow the employment of low percentage of FO in feeds help to reduce the load of several toxic pollutants in the fillets of European seabass.