Effects of eicosapentaneoic acid on innate immune responses in an Atlantic salmon kidney cell line in vitro

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Low Omega-3 Levels in the Diet Disturbs Intestinal Barrier and Transporting Functions of Atlantic Salmon Freshwater and Seawater Smolts

Due to a limited access to marine raw materials from capture fisheries, Atlantic salmon feeds are currently based on mainly plant ingredients (75%) while only 25% come from traditional marine ingredients including marine fish meal and fish oil. Thus, current feeds contain less of the essential omega-3 fatty acids. The aim of the study was to assess the impact of different omega-3 levels in fish feed on intestinal barrier and transporting functions of Atlantic salmon freshwater and seawater smolts. Atlantic salmon were fed three levels of omega-3 (2, 1 and 0.5%) and fish performance was followed through smoltification and the subsequent seawater acclimation. Intestinal barrier and transporting functions were assessed using Ussing chamber methodology and combined with transcript analysis of tight junction related proteins and ion transporters. A linear decrease in growth was observed with decreasing omega-3 levels. Low (0.5%) inclusion of omega-3 impaired the barrier function of the proximal intestine compared to 2% inclusion. Further, low levels of omega-3 decrease the transepithelial electrical potential across the epithelium indicating disturbed ion transport. It can be concluded that low dietary levels of omega-3 impair somatic growth and intestinal function of Atlantic salmon.publishedVersio

Dietary Level of the Omega-3 Fatty Acids EPA and DHA Influence the Flesh Pigmentation in Atlantic Salmon

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Toxicological evaluation of a fish oil concentrate containing Very Long Chain Fatty Acids

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Improved fillet quality in harvest-size Atlantic salmon fed high n-3 canola oil as a DHA-source

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Omega-3 Futures in Aquaculture: Exploring the Supply and Demands for Long-Chain Omega-3 Essential Fatty Acids by Aquaculture Species

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Different Dietary Ratios of Camelina Oil to Sandeel Oil Influence the Capacity to Synthesise and Deposit EPA and DHA in Zucker Fa/Fa Rats

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Long-term feeding of Atlantic salmon with varying levels of dietary EPA+DHA alters the mineral status, but does not affect the stress responses after mechanical delousing stress

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Kunnskapskartlegging pigmentering i laks

Gjennomgangen av data på filetfarge i norsk oppdrettslaks viser at det har vært en viss nedgang i farge, fra 2012 og frem til om lag 2021. Deretter har fargenivået økt noe. Variasjonen i filetfarge er blitt større, med pigmentnivå fra 4 til 8 mg/kg. Tilbakemeldinger fra oppdrettere bekrefter at flertallet av de spurte har problem med å oppnå ønsket farge i filet, samtidig som ønsket farge kan variere mellom 22-27 i SalmoFan score og 5-7 mg astaxanthin/kg. Noen produsenter opplever redusert innfarging på mellom 20-40 % av slaktet fisk, mens andre opplever det på under 2 %. Det er gjort ulike tiltak for å forbedre filetfarge, innholdet av astaxanthin i fôr er økt til 50-70 mg/kg, og flere oppdrettere har økt innholdet av EPA/DHA og vitaminer. Enkelte faktorer bidrar til å forklare variasjonen i innfarging. Filetfarge var sterkt positivt korrelert med slaktevekt, og variasjon i farge var også knyttet til når på året fisken slaktes, der høsten peker seg positivt ut. Antallet uker med mekanisk avlusning på en lokalitet hadde en negativ effekt på innfarging. Det var også en negativ korrelasjon mellom astaxanthin-innhold i fileten og tilvekst (TGC/VF3) og fôrfaktor, og de fleste oppdrettere meldte om problemer med farge etter perioder med hurtig vekst. Der det var tilgjengelige data på innholdet av EPA og DHA i filet ble det funnet en positiv korrelasjon med sum omega-3 og astaxanthin nivå i filet. Effekten av omega-3 er også funnet i vitenskapelige forsøk. Det ble i tillegg funnet en tydelig effekt knyttet til smoltprodusent på filetfarge ved slakt. Årsakene til dette kan ikke fastslås og bør undersøkes nærmere.Kunnskapskartlegging pigmentering i lakspublishedVersio

Nutritional value of Ethyl Ester oils in fish diets: A review on their potential impact on growth and health

The Norwegian Pelagic sector plays a significant role in producing pelagic fish products for human consumption, including concentrated marine omega-3 fatty acids (FA) used in dietary supplements. To fully utilize fish sources, the sector must explore to use valuable side stream products as ingredients in aquaculture feeds, such as ethyl ester (EE) oils derived from production of concentrated omega-3 FA for dietary supplement. Despite annual production of approximately 10,000 tons of EE oils in Norway, there is limited knowledge about their suitability in aquafeeds. This knowledge gap may stem from the absence of EE in aquatic animals' natural diets, unlike in human dietary supplements. Moreover, varying FA compositions of EE oils used in different fish trials present challenges in drawing definitive conclusions about their effects. Fish metabolism differs from mammals in digesting dietary lipids, lacking the necessary lipase enzymes for monoacylglycerol production during TAG digestion. This may affect the efficiency of lipid transport and metabolism in salmonids, potentially influencing intestinal health and overall lipid metabolism. Furthermore, studies suggest lower digestibility of EE oils compared to free FA or TAG forms, indicating potential limitations in their re-esterification process in enterocytes. Concerns also arise regarding ethanol release during EE hydrolysis in the gut and its potential impact on intestinal health. Additionally, EE oils' susceptibility to oxidation suggests variations in stability in feeds depending on composition and antioxidant content. In SalmoE2, we aim to assess the safety and suitability of EE oils in salmonid diets, addressing the challenge of locally sourcing sustainable ingredients with low CO2 footprints. Understanding the effects of EE oils on salmon and trout performance, health, and fillet quality is crucial for both the pelagic industry and feed producers, optimizing the exploitation of side stream products while promoting sustainable marine product usage. Quantitative data on safety, optimal inclusion, and potential benefits of EE oil use in salmonid diets are essential.Nutritional value of Ethyl Ester oils in fish diets: A review on their potential impact on growth and healthpublishedVersio