PARASITIC FAUNA OF MALAPTERURUS ELECTRICUS AND PARACHANNA OBSCURA FROM LEKKI LAGOON, LAGOS, NIGERIA

Abstract

Host condition factor and gastrointestinal parasites in Malapterurus electricus and Parachanna obscura in Lekki lagoon, Lagos, Nigeria were investigated from September, 2014 to February, 2015. Eighty (80) fishes of Malapterurus electricus and eighty (80) of Parachanna obscura were caught and dissected for intestinal helminth parasites and protozoa. Condition factors of all individuals were determined. Median condition (K < 2.17 and K > 2.17) for Malapterurus electricus, (K < 1.02 and K > 1.02) for Parachanna obscura were used in grouping the individuals. Protozoa infection in the gut includes; myxosporidia and coccidians. Heterogeneous infection of these protozoa in low condition Parachanna obscura were; Myxosporidia, 0.20, Coccidia, 0.10 and high condition individuals, 0.10, 0.15 respectively. There were no coccidian infection in M. electricus, but myxosporidia in low and high condition individuals were 0.15 and 0.10. The rate of infection of Electrotaenia malopteruri, a cestode, specific to M. electricus was higher among high condition individuals, 0.15, compared low condition individuals, 0.10. Procamallanus sp, had the highest prevalence among the high condition individuals of Parachanna obscura, the trend was; High Condition M.electricus (0.10) < Low Condition P.obscura (0.15) < Low Condition M.electricus (0.20) < High Condition P.obscura (0.25). Infected individuals of low condition factor (K < 2.17) of Malapterurus electricus had a greater histopathological alteration index (HAI, 18.0) compared to the high condition individuals (HAI, 8.0). These individuals had from mild to severe ulceration of the mucosa and congestion of the blood vessels. In infected individuals of low condition factor (K < 1.02) of Parachanna obscura, there were mucosal edema and haemorrhage in their intestinal walls. They also had greater histopathological alteration index (HAI, 22.0) compared to the high condition individuals (HAI, 6.0). Prevalence of gastrointestinal parasitic fauna in low condition host could be an indicator of stress in fish