Omega-3 long-chain polyunsaturated fatty acids in Atlantic salmon: Functions, requirements, sources, de novo biosynthesis and selective breeding strategies

Abstract

The aquaculture industry is a substantial user of wild-sourced fish oil to supply omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFAs) in fish diets, which are required by many economically important farmed fish species, particularly Atlantic salmon (Salmo salar L.). Fish oil is commonly replaced with plant-based oils as more environmentally and economically sustainable substitutes due to concerns regarding over-fishing of wild stocks and increasing demand. One potential strategy to meet the physiological requirement for n-3 LC-PUFA is to improve n-3 LC-PUFA biosynthesis in salmon through selective breeding and strain enhancement. The objective of this review is to discuss strategies to supply sufficient levels of n-3 LC-PUFA to Atlantic salmon through the diet and de novo biosynthesis through selective breeding and salmon strain enhancement. This review provides an overview on the functions of n-3 LC-PUFA in Atlantic salmon, dietary requirements, source and supply of n-3 LC-PUFA in aquaculture feeds, and biosynthesis of n-3 LC-PUFA in fish. Several relevant studies have revealed the genetic influences on n-3 LC-PUFA biosynthesis and storage in Atlantic salmon. The results of the present review show that selective breeding of high n-3 PUFA-producing Atlantic salmon could be an effective strategy to improve the amount of EPA and DHA stored in tissues and reduce reliance on dietary sources of n-3 LC-PUFA such as fish oil.