Omega-3 and alpha-tocopherol provide more protection against contaminants in novel feeds for Atlantic salmon ( Salmo salar L.) than omega-6 and gamma tocopherol

Abstract

Extended use of plant ingredients in Atlantic salmon farming has increased the need for knowledge on the effects of new nutrients and contaminants in plant based feeds on fish health and nutrient-contaminant interactions. Primary Atlantic salmon hepatocytes were exposed to a mixture of PAHs and pesticides alone or in combination with the nutrients ARA, EPA, α-tocopherol, and γ-tocopherol according to a factorial design. Cells were screened for effects using xCELLigence cytotoxicity screening, NMR spectroscopy metabolomics, mass spectrometry lipidomics and RT-qPCR transcriptomics. The cytotoxicity results suggest that adverse effects of the contaminants can be counteracted by the nutrients. The lipidomics suggested effects on cell membrane stability and vitamin D metabolism after contaminant and fatty acid exposure. Co-exposure of the contaminants with EPA or α-tocopherol contributed to an antagonistic effect in exposed cells, with reduced effects on the VTG and FABP4 transcripts. ARA and γ-tocopherol strengthened the contaminant-induced response, ARA by contributing to an additive and synergistic induction of CYP1A, CYP3A and CPT2, and γ-tocopherol by synergistically increasing ACOX1. Individually EPA and α-tocopherol seemed more beneficial than ARA and γ-tocopherol in preventing the adverse effects induced by the contaminant mixture, though a combination of all nutrients showed the greatest ameliorating effect.

Dietary pesticide chlorpyrifos-methyl affects arachidonic acid metabolism including phospholipid remodeling in Atlantic salmon (Salmo salar L.)

“…The decreased content of membrane cholesterol observed in the present work may further influence membrane structure and possibly affect biosynthesis of steroid hormones, bile acid and vitamin D. Perturbed cholesterol homeostasis by contaminants has been demonstrated in numerous mammalian and teleostean studies (Elskus et al, 2005). A recent study reported that cell membrane stability and vitamin D metabolism were the main responses affected in salmon hepatocytes exposed to a contaminant mixture containing CLP (Softeland et al, 2016). Another recent study revealed effects on cholesterol metabolism and lysophospholipids in salmon hepatocytes exposed to pirimiphos-methyl (Olsvik et al, 2017b).…”

“…CLP induced changes in physiopathological alterations, and hematological characteristics have also been reported in Tilapia guineensis (Chindah et al, 2004) and Cyprinus carpio carpio (Ural, 2013). On a biochemical level, recent in vitro studies with Atlantic salmon hepatocyte showed perturbation of lipid metabolism as one of the main non-AChE target effects of CLP exposure (Softeland et al, 2014, Softeland et al, 2016, Olsvik et al, 2015.…”

“…Chlorpyrifos-methyl (CLP-m) has been identified in feed ingredients by the ARRAINA EU-project and in fish feed by Norwegian feed surveillance as one of the new potential undesirables (Nacher-Mestre et al, 2014). Recent studies with Atlantic salmon hepatocytes have reported perturbation of lipid metabolism as one of the main target effects of CLP exposure (Softeland et al, 2014, Softeland et al, 2016, Olsvik et al, 2015. At the same time, the European Union (EU) pesticide maximum residue limit (MRL) for animal feeds do not include the nonpersistent organophosphate (OP) pesticides (EC, 2002) such as CLP-m. EU MRL legislation comprises most food commodities (EC, 2005), but for feed (crops exclusively used for animal feed purposes) and fish, harmonized EU MRLs are not yet established.…”

Metabolic and immune responses of Chinook salmon (Oncorhynchus tshawytscha) smolts to a short‐term poly (I:C) challenge

“…Metabolomics involves the study of chemical processes mediated by metabolites, and with the help of analytical techniques, statistical differences can be observed among samples and metabolic signatures identified as biomarkers for specific challenges (Alfaro & Young, 2018). Past metabolomic studies of salmonids focused on nutrition Jasour et al, 2017;Roques et al, 2018a;Wagner et al, 2014) and the metabolic effects of contaminants (Olsvik et al, 2015(Olsvik et al, , 2017Olsvik & Søfteland, 2018;Softeland et al, 2014;Softeland et al, 2016), among others. Recently, metabolomics has been used to demonstrate the effects of pre-sampling handling and sedation practices on O. tshawytscha biochemistry (Young et al, 2019).…”

Diet and Life Stage-Associated Lipidome Remodeling in Atlantic Salmon

“… 17 Lipidomics aims to take a snapshot of all lipid species present in a sample at a given time. This is a powerful tool for assessing global changes in the lipidome and has been successfully applied to study immunology in grouper 19 and toxicology in salmon 20 and to assess the freshness of commercial salmon filets. 18 Lipidomics has not yet been widely utilized in nutritional studies of aquaculture species, with most studies employing traditional lipid profiling approaches such as fatty acid methyl ester analysis 21 and thin-layer chromatography.…”