A novel marine algal oil containing both EPA and DHA is an effective source of omega‐3 fatty acids for rainbow trout (Oncorhynchus mykiss)

Abstract Novel sources of omega‐3 fatty acids (FAs) are essential for the sustainable development of the aquaculture industry. In the present study, we assessed the response of the fish to a novel algal oil as a source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for rainbow trout ( Oncorhynchus mykiss ) diets. Our results show that the palatability of the diets was maintained with high inclusion levels (up to 10%) of algal oil. The digestibility of omega‐3 FAs was compared among diets containing 10% fish oil (control diet) and diets with no omega‐3 lipid sources (0AO) or increasing levels of algal oil (2.5, 5, and 10% for diets 2.5AO, 5AO, and 10AO, respectively). The digestibility of EPA and DHA was above 99% and was only significantly decreased in the 0AO diet. The FA profile of the muscle was found to reflect that of the diets, suggesting that, when high levels of omega‐3 are included in the diet of rainbow trout, they are deposited in the muscle rather than used for metabolic processes. The growth and the blood parameters of the animals were optimal for all the treatments in the safety trial, with algal oil inclusion levels up to 6%. All these results in combination show that Veramaris® algal oil containing EPA and DHA can be used as an efficient source of omega‐3 FAs for salmonids.