Fatty‐Acid Profile of Total and Polar Lipids in Cultured Rainbow Trout (Oncorhynchus mykiss) Raised in Freshwater and Seawater (Croatia) Determined by Transmethylation Method

Abstract

Fatty acids from total lipids and polar lipids in cultured rainbow trout (Oncorhynchus mykiss) raised in seawater (SW) and freshwater (FW) were identified and quantified from the muscle samples in January, April, and July. The highest total lipid and polar lipid amounts were found in April. July contents of total lipids were low, but percent of the polyunsaturated fatty acids (PUFAs) was high in SW and FW environment (particularly n-3 PUFAs). Variety of 17 fatty acids was identified by GC-FID after transmethylation. The predominant fatty acids in rainbow trout from SW and FW were: docosahexaenoic acid among n-3 PUFAs, palmitic acid among saturated fatty acids (SFAs), and oleic acid among monounsaturated fatty acids (MUFAs). Appreciably higher n-3/n-6 ratio was found in total lipids in April (6.40, FW fish) and in polar lipids in July (18.76; SW fish). High n-3/n-6 ratio in total lipids and polar lipids of rainbow trout from SW and FW, besides beneficial n-3/n-6 ratio in the commercial fish food, could be characteristic for the local environmental conditions (Croatia).

Proximate and fatty acid composition in raw and cooked muscle tissue of farmed rainbow trout (Oncorhynchus mykiss) fed with commercial fishmeal

“…It is significant to note that the rainbow trout from Hidalgo contains a broad variety of fatty acids and their isomers, especially of linolenic acid (C18:3n‐3) and DHA (C22:6n‐3), according to other studies in the same species of fish (Asghari et al, ; Staver et al, ; Unusan, ). However, the amounts of EPA and DHA are smaller in this study.…”

“…It has been suggested to be a better index for comparing the relative nutritional value of different species (Hossain, ). In freshwater fish, the range is from 1 to almost 4, in contrast to marine fish, which range from 5 to more than 10 (Staver, Jerković, Giacometti, Malenica, & Marijanović, ).…”

“…There are several studies of the fatty acid composition of different species of farmed fishes and wild fishes (Gladyshev, Sushchik, Gubanenko, Demirchieva, & Kalachova, ; Larsen, Quek, & Eyres, ; Weber, Bochi, Ribeiro, Victório, & Emanuelli, ; Ersoy, ), but the fatty acid composition of fish lipids and the nutritional value vary not only among species but also within species, depending upon season, geographic origin, age, feed and wild or cultured types (Danabas, ; Staver et al, ; Asghari, Zeynali, & Sahari, ; Yildiz et al, ).…”

Fatty acid composition in the fillets of rainbow trout grown in different conditions

“…The ratio of n‐3/n‐6 fatty acids is high in consumed trout, while with age, it declines in the muscles and increases the skin . Depending on the feed and the seasons, the n‐3/n‐6 fatty acid ratio varies, but it is never low . However, these fish contain a significant amount of cholesterol , which has essential functions in human body.…”

Polyploidy affects growth, fillet composition, and fatty acid profile in two year old rainbow trout, Oncorhynchus mykiss

“…Chylomicrons subsequently move through the lymphatic system and bloodstream where lipoprotien lipase converts triacylglycerols to fatty acids and glycerol. These fatty acids are then oxidized for fuel or reesterfied for storage (Staver et al, 2012). Following storage and when needed for energy, fatty acids are hydrolyzed through the process of lipolysis.…”