Biomass of the oleaginous yeast Rhodotorula toruloides as feed ingredient in the diet of Arctic char (Salvelinus alpinus): impact on quality; safety and sensory outcome

Abstract

ABSTRACT The aim of this study was to test the impact of replacing vegetable oils commonly used in the feed of Arctic char (Salvelinus alpinus) with biomass of the oleaginous yeast Rhodotorula toruloides. For that, a control feed containing vegetable oils and an experimental feed including yeast biomass at 15% level, were fed to Arctic char. Sensory properties of the fish were tested. The content of undesirable compounds in the new feed ingredient were evaluated. Selected heavy metals and organic pollutants were measured in the yeast biomass and the levels found were below the limits of the regulations defined by the European Union. Moisture and ash contents were similar between the two feeds. Hepatic activity of 7-ethoxyresorufin-O-deethylase was evaluated between the two fish groups and no significant differences were observed. The sensory analysis conducted on heat treated fish fillets with untrained volunteers showed no perceptible sensory difference.