A cross-sectional Analysis and Immunological Study of Parasitic Infections in Solea aegyptiaca and Tilapia zillii from Qarun and Wadi El-Rayan Lakes

Nowadays, Qarun and Wadi El-Rayan lakes are exposed to adverse ecological changes that have led to the loss of fish stocks. In this study, we recorded the most common parasitic infestations in these lakes regarding bad water quality parameters and the associated parasitological and pathological effects. A total of 274 fish species were categorized into 205 Tilapia zillii, and 69 Solea aegyptiaca were randomly collected from Wadi El Rayan lakes; private fish farms and Shakshouk area of Lake Qarun in Fayoum governorate, Egypt. Total prevalence of parasitic infection was 33.9 %. All of the examined fish were positive for one or two mixed parasitic infections. Trichodina spp., Gyrodactylus spp., Cichlidogyrus tilapiae, Centrocestus formosanus encysted metacercaria and Livoneca redmanii were detected in 4.3%, 11.2 %, 13.6 %, 14.6% and 4.3% of infected fishes respectively. The immunological response of fish to parasitism was detected via the upregulation in levels of TNFα and IL-1β genes with significant differences (P =0.000). The obtained physicochemical water parameter results from studied places indicate that ammonia, nitrite, nitrate, and phosphate concentrations were above the specified permissible limits. The histopathological lesions associated with parasitic infestation described severe hyperplasia, degeneration and necrosis of gill lamellae; congestion of branchial blood vessels, associated with the presence of Trichodina spp., and encysted C. formosanus in gills. These all highlight how important it is to comprehend how these parasites can affect fish health, productivity and the aquaculture industry. However, the presence of these parasites in fish-rearing water requires more financial and management efforts.