Removal of persistent organic pollutants from Atlantic salmon (Salmo salar L.) diets: Influence on growth, feed utilization efficiency and product quality Jan Josef Olli a, ⁎, Harald Breivik b , Turid Mørkøre c , Bente Ruyter c , Johan Johansen d , Patric Reynolds d , Olav Thorstad e , Gunnar Berge f a AVS Chile SA, Casilla 300, Puerto Varas, Chile b Neperdo Biomarine, Uranusveien 22, NO-3942 Porsgrunn, Norway c Nofima Marin AS, P.O. Box 5010, NO-1432 Ås, Norway d Gildeskål Forskningsstasjon AS (GIFAS), NO-8140 Inndyr, Norway e Pronova BioPharma Norge AS, P.O. Box 2109, NO-3202 Sandefjord, Norway f Pronova BioPharma Norge AS, P.O. Box 420, NO-1327 Lysaker, Norway abstract article info Article history: Received 6 July 2010 Received in revised form 27 September 2010 Accepted 30 September 2010 Keywords: Atlantic salmon (Salmo salar) Growth rate Feed utilization efficiency Product quality Short-part distillation Persistent organic pollutants Atlantic salmon were fed diets with fish oil, either normal (control group) or cleansed for persistent organic pollutants (POPs) as the sole lipid source from smolt stage to harvest size. The POPs were removed using short-path distillation, aided by a working fluid, and were highly efficiently removed resulting in low dietary levels. Each diet was fed to fish in four cages, 5 × 5 × 5 m, and the fish were fed ad libitum by aiming at least 10% over feeding every day. Although the growth rate was low during the first months of the trial, the growth rate was good in total, from sea transfer to harvest size. The fish fed the diet with the cleansed oil grew significantly better than the control fish in 1 of the 5 periods. Feed conversion ratio (FCR) was significantly lower for the cleansed oil group for 2 of the 5 periods, as well as the total trial period. Nutrient digestibility was measured when the fish were around 1 kg and at termination of the study, and there were no significant differences between the dietary groups. There were no significant differences in dress out loss and condition factor, and hepatosomatic index was found to be significantly higher for the control group at the last sampling. Colour was measured by using DSM Salmofan at four points on the fillet as well as in the Norwegian Quality Cut, and found to be significantly higher for the control fish in one intermediate sampling. At the last sampling, there was however a tendency of higher colorization for the cleansed oil group. For fillets sampled at the termination for quality assessments, there were only minor differences in muscle pH, firmness, colour and consumer test. The muscle pH was significantly higher and muscle firmness tended to be higher for the cleansed oil group. The levels of POPs in fillets were highly significantly lower in fish fed diets with the cleansed oil. In conclusion, none of the parameters measured in the present study indicate any negative effects of the cleansing process in Atlantic salmon from smolt stage to harvest size. On the contrary, the study suggests positive effects on growth, feed utilisation efficiency and product quality. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Persistent organic environmental pollutants (POPs), such as polychlorinated biphenyls (PCBs), dioxins [polychlorinated dibenzo- p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs)] and polybrominated diphenyl ethers (PBDEs) have been getting more attention because of their negative impact on human health the recent years, and increasing consumer concerns about food safety in general. The levels of POPs have been found to be well below recommended action levels in farmed Atlantic salmon in Norway (http://www.nifes.no/index.php?page_id=137) and in Atlantic salmon from Europe, and North- and South America (Hites et al. 2004). However, the latter authors reported concerns regarding the concerted effects of all POPs. They found the levels of POPs to be higher in farmed Atlantic salmon compared to wild pacific salmon, and higher in farmed salmon from Europe than in farmed salmon from America. Higher levels in farmed salmon compared to wild salmon is also reported by Carlson and Hites (2005). Foran et al. (2005a) reported that consumption of farmed salmon at relatively low frequencies resulted in elevated exposure to dioxins and dioxin-like compounds with commensurate elevation in estimates of health risks, and Foran et al. (2005b) proposed that recommended levels of EPA and DHA intake (1 g/day) cannot be achieved solely from farmed or wild salmon while maintaining an acceptable level of carcinogenic risk. Ikonomou et al. (2007) reported on the other hand no concerns regarding consumption of farmed or wild Aquaculture 310 (2010) 145–155 ⁎ Corresponding author. Stabbursnes naturhus, NO-9710 Indre Billefjord, Norway. Tel.: +47 958 20 286. E-mail address: janolli@online.no (J.J. Olli). 0044-8486/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2010.09.044 Contents lists available at ScienceDirect Aquaculture journal homepage: www.elsevier.com/locate/aqua-online