The composition of fatty acids stored in liver, muscle and fat tissues of the African lungfish Protopterus annectens (Owen, 1839)

Abstract

The composition and profile (%) of fatty acids stored in liver, muscle, and fat tissues of the fresh-water African lungfish Protopterus annectens were determined by gas chromatography. High content of total fatty acids (TFA) was found in fat (62.06 ± 3.4 g/100 g) followed by liver (50.68 ± 4.72 g/100 g) and muscle tissues (10.9 ± 0.81 g/100 g). Saturated fatty acids (SFA) formed 72.9% TFA in the liver and muscles and 53.3% in fat. Fat was rich in polyunsaturated fatty acids (PUFA), containing 31.1%, while muscle and liver contributed 12.9 and 10.6 % respectively. Fat and liver also contained, respectively, 9.59 ± 1.1 and 8.38 ± 1.9 g/100 g of monounsaturated acids (MUFA) compared to 1.56 ± 0.3 g/100 g in muscles. The major SFA were C16:0, C18:0 and C14:0. The MUFA were characterized by the Oleic (C18:1n9c) and Palmitoleic (C16:1) acids. The major PUFA in all three types of tissues was the Linoleic acid (C18:2n6c), while C20:3n6 was detected in fat only, and C18:3n3 was detected in muscles only. The n-3/n-6 ratio in the muscles was 0.5. The results of this study show that fatty acid composition in the African lungfish P. annectens can considerably vary, depending on the storage organ. According to the present results, P. annectens was considered a semi-fatty fish, storing its lipids in muscles, liver and fat tissues. These organs are potential source of essential fatty acids and may play an important role in human health. More focus on lipid extraction from P. annectens is recommended.

Fatty Acids and Amino Acids Content of Heterotis niloticus (Cuvier, 1829) and Protopterus annectens (Owen, 1883) from Lake Alau, Northeast Nigeria

“…The total acid value (TAV) was slightly higher in Protopterus annectens than Heterotis niloticus in the current study. This result conflicts with the previous studies on P. annectens from other regions 16 . Oleic acid (C18:1), a monosaturated omega-9 fatty acid is the most abundant fatty acid in P. annectens and H. niloticus in the current study.…”

“…This is consistent with the work of Osibona et al 8 , who reported that C18:1was the dominant fatty acid in Clarias gariepinus and Tilapia zilli from Makoko and Epe Landing sites in Lagos, Nigeria. When compared with muscle oleic acid contents in P. annectens (0.82±029 g 100 gG 1 ) and H. niloticus (21.42±0.14 g 100 gG 1 ) reported by the previous study 16,17 the content of fatty acid in the current study were lower. Also, the oleic level in this study was comparatively low to the values reported in four freshwater fish species from Maga Lake, Cameroon 17 .…”

“…Palmitic acid (C16:0), the predominant saturated fatty acid in both freshwater and marine fish 18 , was very low in this study as compared to 2.3±0.05 g 100 gG 1 in P. annectens 16 and 20.07±0.03 g 100 gG 1 in H. niloticus 17 . Also, these results differ from the findings of Osibona et al 8 , who reported 22 and 32.2% for C. gariepinus and T. zilli, respectively.…”