495 Rainbow Trout Composition and Fatty Acid Content in Estonia L. Timberg 1,2 , R. Kuldjärv 1,2 , K. Koppel 1,2 and T.Paalme 1,2 1 Competence Centre of Food and Fermentation Technologies, Akadeemia tee 15B, 12618 Tallinn, Estonia; e–mail: loreida@tftak.eu; rain@tftak.eu; kadri@tftak.eu 2 Tallinn University of Technology, Department of Food Processing, Ehitajate tee 5, 19086 Tallinn, Estonia; e–mail: tpaalme@staff.ttu.ee Abstract. Rainbow trout (Oncorhynchus mykiss) is the most popular aquaculture species in Estonia. The aim of the present study was to examine and compare moisture, protein, lipid and fatty acid (FA) compositions in Rainbow trout from different fish farms in Estonia and that farmed in Finland and Norway. The total lipid content in different Rainbow trout varied more than 5.5 fold, but FA proportions were very similar in all Rainbowtrout. However, it is important to note that Estonian farmed Rainbow trout had generally lower lipid content and therefore also a lower amount of essential FAs. Key words: Fatty acid, lipid, Rainbow trout (Oncorhynchus mykiss) INTRODUCTION Natural resources of fish can no longer fulfil demands of fish consumers; the shortage is forcing the aquaculture sector to expand. There are about 15 fish farms in Estonia where Rainbow trout is cultured. The annual volume of Estonian farmed Rainbow trout is about 700 tons, but many fish farms are expanding; production is expected to double in the next few years. Therefore, the Estonian aquaculture sector is interested in producing Rainbow trout which has high nutritional value, stabile quality and is also compatible with Rainbow trout farmed in other countries. Fat is one of the most important components of fish meat. It attracts consumers’ attraction due to the fatty acid (FA) profile, especially n–3 and n–6 FAs (Ruxton et al., 2004; Breslow, 2006). Therefore, the main aim of the study was to characterize and compare the moisture, protein, lipid and FA profiles of Rainbow trout from different fish farms in Estonia and imported Rainbow trout available in Estonian supermarkets. Experiment design Rainbow trout samples from ten different aquaculture facilities in Estonia were acquired (samples E1–E10). Fish were gutted, packed in ice and transported to the laboratory on the day of slaughter; all analyses were performed the next day. Three samples of Rainbow trout (imported) cultured in other countries were purchased from Estonian supermarkets (sample T1–Finland, T2–Norway, and T3–Finland). The imported trout had been slaughtered 4–6 days before purchase and had already been gutted, packed in plastic bag, and transported to the laboratory within an hour after purchase, where the fish was immediately packed in ice. All analyses were performed Agronomy Research 9 (Special Issue II), 495–500, 2011