Fatty acid profile of Nile and Red hybrid tilapias reared in intensive and extensive systems

Long chain n-3 and n-6 polyunsaturated fatty acids which are present in many marine fish have long been found to confer beneficial effects on human health. As the world fish stock declines due to over fishing and depletion in the quality of marine environment, fish proteins are increasingly being sourced from fish farms using many water bodies. Information on fatty acid profile of farmed fish especially from aquaculture industry aids consumers to make pertinent dietary decisions. A study was conducted to examine the fatty acid composition of Nile and Red tilapia harvested from intensive culture system. Twenty two samples of Nile tilapia and 16 samples of Red tilapia cultured intensively were used in this study. All samples were subjected to total fatty acid extraction and their fatty acid composition was determined using gas liquid chromatography. Results showed that no significant difference in the total concentration of saturated fatty acids as a percentage of total fatty acids present between intensively (46.14%) and extensively (48.13%) cultured Nile tilapias and between Nile (46.14%) and Red tilapias (46.42%) reared in the intensive system. For monounsaturated fatty acids, the total concentration was lower (p<0.05) in extensively (19.76%) cultured compared with intensively (31.17%) cultured Nile tilapias. For n-3 polyunsaturated fatty acids, the concentration was higher (p<0.05) in tilapias from extensive system (19.57%) compared with those from intensive system (8.14%). But n-6 polyunsaturated fatty acids concentration of intensively cultured Nile (14.35%) and Red (16.32%) tilapias were higher (p<0.05) compared with extensively cultured tilapias (12.55%). For n-6:n-3 polyunsaturated fatty acids ratio intensively cultured Nile tilapias had higher (p<0.05, 1.88 to 2.24) than extensively cultured Nile tilapias (0.74). Different concentration of fatty acid composition of Nile tilapias cultured in the different systems could be due to the different nutrient composition of the feed consumed by these fish. Manipulation of the sources of poly unsaturated fatty acids in the feed of farmed tilapias could be a novel approach to enhance the n-6:n-3 polyunsaturated fatty acids ratio of intensively cultured tilapias.