Fatty Acids Composition of Two Commonly Consumed Freshwater Fishes (Clarias gariepinus and Chrysichthyes nigrodigitatus) from the Cross River at Ahaha, Obubra, Nigeria

Abstract

Fish oils are good sources of essential fatty acids beneficial to human health by helping the body in preventing diseases and enhancing proper growth and development. This study is aimed at investigating the quantitative and qualitative composition of fatty acids in two commonly consumed and most abundant freshwater fishes (Clarias gariepinus and Chrysichthyes nigrodigitatus) from the Cross River at Ahaha, Obubra. The oil was converted to fatty acids methyl esters (FAME) and the fatty acids evaluated by gas chromatography – mass spectrometry using retention time method. The fatty acids profiles include saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). The composition varied from 0.06 – 24.00% of SFAs, 0.23 – 21.40% of MUFAs and 0.23 – 12.22% of PUFAs in the both species. The major SFAs were palmitic (C16:0) and stearic (C18:0) acids while the most abundant MUFA was oleic (C18:1) acid. Dominant PUFAs in the both specie were linoleic (C18:2), eicosapentaenoic (EPA, C20:5) and docosahexaenoic (DHA, C22:6) acids. Quantitatively the composition of various fatty acids was in the order SFAs < MUFAs < PUFAs although not significantly different (p< 0.05) in the species. Chrysichthys nigrodigitatus had higher total fatty acids (TFA), PUFAs and omega –3 / omega –6 ratio than C. gariepinus with higher levels omega -6 fatty acids. The ratios of PUFA/SFA were higher in C. nigrodigitatus although both were greater than the minimum value (0.4) recommended by World Health Organization. The result indicates that the species had high quality essential fatty acids especially DHA and EPA although relatively higher in C. nigrodigitatus. Hence these species have the potentials to serve as the natural dietary supplement for all important omega -3 fatty acids.