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

Abstract

The aim of this study was to determine the influence of different feed composition and cultivation on the composition of fatty acids, their relationships, and the cholesterol content in the tissue of rainbow trout (Oncorhynchus mykiss). Trout were reared in ponds at two different altitudes and raised on different feeds. The total amount of monounsaturated fatty acids in fillets of both groups showed no statistically significant difference. However, higher levels of n‐6 fatty acids were found in Pond I trout fillets than in Pond II fillets, while Pond II fillets contained almost even amounts of n‐3 and n‐6 fatty acids. Total cholesterol content in Pond I trout fillets was significantly lower (p < 0.05) than in Pond II fillets. The results indicate that the final composition of the trout fillets was mostly dependent on the feed the live fish had consumed; the altitude of the ponds had less effect. Also, both groups of trout could be used in the human diet as biologically valuable foods.Practical application: Our results show influence of altitude, feed, and fatty acid composition of feed on trout fillets. The average fatty acid level in the trout fillets increased in the order SFA <MUFA <PUFA. Trout fillets contain low levels of cholesterol but high levels of EPA, DPA, and DHA. These facts are important for fish industries and aquaculture producers to design a healthy food.The trout, although grown at two different altitudes, showed differences in their basic chemical composition and in their fatty acid composition which more tended to be related to the composition of their feed. Low cholesterol levels and high levels of EPA, DPA, and DHA, as well as reasonably favorable ratios of n‐3 and n‐6 fatty acids indicate that the trout from both groups could be suitable for use in the human diet as biologically valuable foods.