Diet, size and location as determinants of n-3 long-chain polyunsaturated fatty acid content in farmed Atlantic Salmon (Salmo salar )

Abstract

We explored how currently manufactured feeds, under real‐world conditions and across geographically distinct locations, promoted flesh n‐3 long‐chain polyunsaturated fatty acid (LC‐PUFA, i.e. 20:5n‐3 + 22:6n‐3) levels in various life stages of farmed Atlantic Salmon (Salmo salar). Potential effects on flesh LC‐PUFA included: (1) diet and fish weight at one Canadian east coast farm, (2) diet and farm location across six east coast farms, and (3) diet and farm location between east and west coast farms. For objectives 1 and 2, salmon were fed a currently manufactured feed (labelled as feeds A, B or C) and harvested at 1, 3 and 5 kg. LC‐PUFA levels in 5 kg (harvest size) fish were then compared to previously published values for west coast farmed Atlantic Salmon (Obj. 3). Combined results revealed that variability in LC‐PUFA levels was better explained by diet than by fish weight or farm location. Fish size, however, was also important for two reasons. First, feeding a high LC‐PUFA diet early in life appeared important for ensuring high LC‐PUFA levels at harvest size. Second, salmon flesh LC‐PUFA levels increased with fish size, but only when dietary LC‐PUFA was provided above an apparent threshold value (~3000 mg per 100 g or 10% of total fatty acids) that likely promoted LC‐PUFA incorporation and storage. Overall, our comparison makes new recommendations for feed manufacturers and demonstrates that farmed Atlantic Salmon reared under real‐world conditions on currently available salmon feeds were good sources of n‐3 LC‐PUFA to consumers.

A Review of Factors Affecting Farmed Atlantic Salmon (Salmo salar) Welfare in Australia and Beyond

“…A complete assessment of diet composition would comprise a review in itself, especially because different diets are aimed at maximising different traits in salmon. We defer to various other studies on this issue (Gillund and Myhr 2010, Hixson et al 2014, Davidson et al 2016, Emery et al 2016, Harvey et al 2016, McMeans et al 2017, Caballero-Solares et al 2018, Neuman et al 2018, Weihe et al 2018, Foroutani et al 2020, Lovmo et al 2021, Gaffney and Lavery 2022, Goglio et al 2022.…”

Nutritional Quality and Assessment of Contaminants in Farmed Atlantic Salmon (Salmo salar L.) of Different Origins

“…One of the most economically important aquaculture species is the Atlantic salmon (Salmo salar L.), with current production exceeding 2.6 million tonnes [2]. Currently, salmon is intensively farmed in many parts of the world, especially in Norway, Scotland, Canada, and Australia [3].…”