Polyunsaturated fatty acids and nutritional quality of five freshwater fish species cultivated in the western region of Santa Catarina, Brazil

Abstract There is a paucity of information about the chemical composition of commercially important freshwater fish species (Nile tilapia, bighead carp, grass carp, common carp and silver carp) cultivated in the western region of Santa Catarina, Brazil. This study determined the moisture, ash, protein and lipid contents and the fatty acid composition, as well as the nutritional quality of the lipids in fillets of these five freshwater fish species. Moisture was the most prominent fish component (74.7%-81.7%), followed by protein (15.8%-18.8%) and lipids (0.4%-8.2%). Saturated palmitic acid (90-1740 mg/100 g) and monounsaturated oleic acid (70-2260 mg/100 g) were the major fatty acids found in all the fish species. The grass and common carps and Nile tilapia (caged) had high contents of γ-linolenic acid (GLA), with an average of 536 mg/100 g. Bighead carp was the richest source of ω-3 PUFA, mainly eicosapentaenoic (EPA, 400 mg/100 g) and docosahexaenoic (DHA, 620 mg/100 g) acids, and had the highest ω-3/ω-6 ratio of 6.11. The nutritional evaluation of the fatty acid profile indicated that average values were: atherogenicity index (AI) ~0.59, thrombogenicity index (TI) ~0.82, hypocholesterolemic/hypercholesterolemic ratio (H/H ~1.98), polyunsaturated/saturated ratio (P/S) ~0.43 and ω-3/ω-6 ratio ~2.18, values suggesting that the consumption of these freshwater fish species could be of benefit to human health.