Fatty acid metabolism (desaturation, elongation and β-oxidation) in rainbow trout fed fish oil- or linseed oil-based diets

• Main Authors: Giovanni Turchini, David Francis
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 2009
• Subjects: Uncategorized; fatty acid metabolism; fish oil replacement; whole body fatty -acid -balance method; Science & Technology; Life Sciences & Biomedicine; Nutrition & Dietetics; Aquaculture; Whole-body fatty-acid-balance method; SALMO-SALAR L; FRESH-WATER FISH; VEGETABLE-OIL; RAPESEED OIL; MURRAY COD; INTESTINAL ENTEROCYTES; LIPID SOURCES; WHOLE-BODY; OLIVE OIL; PALM OIL; Salmo salar
• Online Access: http://hdl.handle.net/10536/DRO/DU:30020781; https://figshare.com/articles/journal_contribution/Fatty_acid_metabolism_desaturation_elongation_and_-oxidation_in_rainbow_trout_fed_fish_oil-_or_linseed_oil-based_diets/21046930

In consideration of economical and environmental concerns, fish oil (FO) substitution in aquaculture is the focus of many fish nutritionists. The most stringent drawback of FO replacement in aquafeeds is the consequential modification to the final fatty acid (FA) make-up of the fish fillet.However, it is envisaged that a solution may be achieved through a better understanding of fish FA metabolism. Therefore, the present study investigated the fate of individual dietary FA in rainbow trout (Oncorhynchus mykiss) fed a FO-based diet (rich in 20 : 5n-3) or a linseed oil-based diet (LO; rich in 18 : 3n-3). The study demonstrated that much of the 18 : 3n-3 content from the LO diet was oxidised and, despite the significantly increased accretion of D-6 and D-5 desaturated FA, a 2- and 3-fold reduction in the fish body content of 20 : 5n-3 and 22 : 6n-3, respectively, compared with the FO-fed fish, was recorded. The accretion of longer-chain FA was unaffected by the dietary treatments, while there was a greater net disappearance of FA provided in dietary surplus. SFA and MUFA recorded a net accretion of FA produced ex novo. In the fish fed the FO diet, the majority of dietary 20 : 5n-3 was accumulated (53·8 %), some was oxidised (14·7 %) and a large proportion (31·6 %) was elongated and desaturated up to 22 : 6n-3. In the fish fed the LO diet, the majority of dietary 18 : 3n-3 was accumulated (58·1 %), a large proportion was oxidised (29·5 %) and a limited amount (12·4 %) was bio-converted to longer and more unsaturated homologues.