The importance of essential fatty acids and their ratios in aquafeeds to enhance salmonid production, welfare, and human health

Abstract

Long chain polyunsaturated fatty acids (LC-PUFA), namely those from omega-3 (n-3) and omega-6 (n-6) families, are paramount for both fish and human nutrition. Some of these biomolecules cannot be synthesized de novo and must be acquired through the diet, being termed dietary essential fatty acids (EFA). Fish requirements for EFA have traditionally been met through the incorporation of fish oil (FO) in the formulation of aquafeeds. However, with limited supply of FO the aquaculture industry is searching for additional sustainable sources of LC-PUFA. This has significantly shifted the type of ingredients used in aquafeed formulation, namely vegetable oils (VO) deficient in long-chain omega-3, often resulting in imbalanced levels and ratios of fatty acid classes. Such imbalances can negatively affect fish performance and welfare, as well as the levels of health promoting omega-3 LC-PUFA present in fish fillets. Given the relevance that salmonid aquaculture plays in global fish production (principally Atlantic salmon, Salmo salar), as well as its growing role as a source of dietary health promoting omega-3 LC-PUFA for humans, the present review summarizes the scientific knowledge available to date on the dietary requirements for LC-PUFA by salmonids and humans. We discuss the implications of using imbalanced aquafeed formulations upon fish performance and welfare, as well as the subsequent consequences for human nutrition, along with current efforts to replace FO by alternative ingredients such as algal oil (AO) that can safeguard high-quality salmonid products for human consumption.

The characteristics of PUFAs-rich virgin fish oil as affected by size of tuna eye

“…Fish ingest these oils, which subsequently accumulate and enter our food chain. For their typical development, marine finfish necessitate Essential Fatty Acids (EFA), including n-3 High Unsaturated Fatty Acids (HUFA) like Docosahexaenoic Acid (DHA) and Eicosapentaenoic Acid (EPA) (Carr et al 2023). As a migratory species, tuna expands its nomadism as it reaches maturity, necessitating substantial fat deposition for energy storage.…”

Changes in the fatty acid profile of fish oil derived from Pangasius catfish (Pangasianodon hypophthalmus) processing waste due to variations in fish size and heating temperatures

“…34 Additionally, EPA and DHA also hold importance in promoting optimal fish growth and reproduction. [35][36][37][38] Utilizing offal from freshwater fish aquaculture as a supplement in fish diets could be a feasible alternative. 39,40 Moreover, the group size of fish exhibits lower levels of omega-3 fatty acids compared to omega-6 and omega-9 fatty acids (as indicated in Table 2).…”

Optimum eicosapentaenoic acid + docosahexaenoic acid levels for farmed Atlantic salmon: closing the gap between science and commercial practice

“…The added value of AO on providing high levels of EPA + DHA, as well as on maintaining the ratio of these omega-3 EFAs (the optimum omega nutrition concept), includes better health and welfare and better fillet quality, which has been extensively documented for Atlantic salmon in scientific lab-scale trials (Santigosa et al, 2018(Santigosa et al, , 2020(Santigosa et al, , 2023. Fillet quality has further repercussions in human health because Atlantic salmon is considered the most valuable source of EPA and DHA for humans (Horn et al, 2019;Carr et al, 2023;Santigosa et al, 2023) and low EPA+DHA levels lead to low fish fillet quality (Oliva-Teles et al, 2015). Indeed, recent studies have shown that the EPA + DHA levels of commercialized Atlantic salmon fillets have been reduced by more than half in recent decades (Sprague et al, 2016(Sprague et al, , 2020.…”