Biosequestration potentials of Tenuisentis niloticus( Meyer, 1932) (Acanthocephala: Tenuisentidae) on organochlorine pesticide burden in Heterotis niloticus ( Cuvier, 1829) ( Actinopterygii: Arapaimidae) from Lekki lagoon, Lagos, Nigeria

Abstract

This study aimed to investigate the presence of organochlorine pesticide (OCP) residues in Heterotis niloticus and its acanthocephalan parasite, Tenuisentis niloticus .Total protein, glucose, triglycerides, and lipoproteins in the fish were analysed using standard methods, and OCP congeners in the tissues of the fish and parasite were tested using Gas Chromatography-Mass Spectrometry (GC–MS). Superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx), and malondialdehyde (MDA) and other mentioned parameters were tested in the infected and uninfected fish groups. Results showed that of the 18 OCP congeners tested in H. niloticus, 6 were undetected and 10 were of higher concentrations in the intestine than the liver. Only gamma-lindane (γ-HCH) and methoxychlor were higher in the liver than the intestine of the fish. The concentrations of Alpha-Lindane (α-HCH), Beta-Lindane (β-HCH), and Delta-Lindane (d-HCH) in the intestine of the uninfected fish were significantly higher than the concentrations in the intestine of the infected fish, the liver of the infected and the liver of the uninfected (p<0.05).The concentration of Endosulfan sulfate and Dieldrin in the liver and intestine of the uninfected fish was higher than the infected fish (p<0.05). The parasite, Tenuisentis niloticus showed the tendency to depurate α-HCH, β-HCH, d-HCH, Heptachlor epoxide, and Endosulfan I in the infected fish. There were significantly higher (p<0.05) concentrations of SOD and MDA in the uninfected fish than the infected. Endrin exhibited a strong positive correlation (0.763) with Deildrin, which in turn negatively correlated (-0.537) with CAT and GSH (-0.748). The microbial analysis conducted on the fish showed the bacteria genera Staphylococcus, Enterococcus, Bacillus, Pseudomonas, Salmonella, Klebsiella, Escherichia, and Proteus, particularly in the infected fish, were susceptible to plasmid elimination (curing). In line with the expectations that stemmed from the stated hypothesis, the study has demonstrated the novelty of Tenuisentis niloticus in attenuating mainly endosulfan sulfate and dieldrin burden in H. niloticus in Lekki lagoon. The protective role of the parasites on its host found expression in ameliorating the oxidatives stress which may have been inflicted on the fish by the OCP toxicity, although at high parasitic prevalence.