Insight into the correlation between parasitic infestation and heavy metal concentrations in tilapia species inhabiting Lake Nasser, Egypt

Abstract

Ecosystem health and integrity are characterized by parasitic fauna and the presence of pollutants. In this study, we investigate the relationship between heavy metal contamination and parasitic diseases infecting tilapia species (Oreochromis niloticus, Sarotherodon galilaeus and Tilapia zillii) in Khor El Ramla, Lake Nasser and heavy metal (Cu, Fe and Zn) concentrations in fish musculature and water. We aimed to clarify the relationship between heavy metals and parasites and evaluate the suitability of these fish for human consumption. Among 150 examined fish, 49.3% were positive for at least one parasite. Most parasites infecting the fish species were larvae (Clinostomum spp., Euclinostomum spp. and Contracaecum spp.); however, Diplostomatid encysted metacercariae were detected in T. zillii. Acanthosentis tialipiae was the only adult parasite detected in all three fish. Significantly higher concentrations of Cu, Fe and Zn were detected in the musculature of parasite-infected fish than non-infected fish with the exception of T. zillii-infected diplostomatid, which exhibited lower Cu and Fe concentrations. Cu, Fe and Zn concentrations in fish musculature (infected and non-infected) and water, and their bioaccumulation factors (BAFs) at Khor El Ramla were within permissible limits. Significant correlations were detected between Cu, Zn and Fe in the musculature of tilapia and parasitic infections. S. galilaeus infected with parasites exhibited a higher Cu BAF, indicating a greater ability to bioaccumulate Cu. Tilapia fish in this Khor are safe for human consumption provided that they are properly handled and adequately cooked.