Proximate and lipid profile analysis of cultured and wild African catfish, Clarias gariepinus [Burchell]

Abstract

As part of ongoing studies on the lipid profile of farmed fishes in our laboratory, this research work is aimed at investigating the proximate chemical composition and lipid profile of the muscles of the African catfish found in Nigerian waters. Crude protein, ash, moisture, and lipid content of the muscles of wild and cultured African catfish were determined using standard methods. Caloric value was also calculated from the lipid and protein content. Lipids in the muscles and livers of the cultured and wild catfish were extracted using the Bligh & Dyer method of lipid extraction. Extracted lipids were then analyzed by gas chromatography to determine the composition and relative abundance of the fatty acids present. The wild catfish contained 77.83 ± 0.88% moisture, 1.20 ± 0.02% ash and 18.76 ± 0.45% protein while the cultured catfish had 75.58 ± 0.88% moisture, 1.20 ± 0.03% ash and 19.33 ± 0.25% protein content, with no significant difference between the wild and cultured catfish. Both wild and cultured African catfish were found to be lean fish (fat content below 5%). Average caloric value was found to be 1204.4 cal/g and 1200.8 cal/g in the wild and cultured catfish respectively. The percentage of total saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) was higher in the muscles of the cultured catfish (38.86% and 42.83% respectively) than in the muscles of the cultured catfish (36.96% and 41.57% respectively). The cultured African catfish also had more omega-6 polyunsaturated fatty acids (PUFA) than the wild ones, whereas its total omega-3 PUFA was lower. Omega-3 to omega-6 ratios in the wild and cultured catfish were 0.81 and 0.52 respectively. Conclusively, the proximate composition, percentage lipid content and indices of fatty acid content of the wild and the cultured African catfish indicated it to be of both nutritional and physiological benefits to humans.

Keywords: Clarias gariepinus, Fish oil, Omega 3, Omega 6, African catfish.