Survey On Ectoparasites Infestation Of Nile Tilapia (Oreochromis niloticus) Collected From Different Aquatic Habitats In Egypt.

[摘要] This research aims to detect the prevalence of ectoparasites on Nile tilapia collected from threedifferent aquatic habitats in Egypt with histopathological changes of affected tissues by differentectoparasites. During the period between September 2018 and September 2019; a total of 555 Oreochromisniloticus fishes taken from River Nile branch (Al Bahr Al Aazam), fish farm (a farm in Kafr el Sheikh) anddrainage canal (Bats Drain at Fayoum governorate). The percentage of infection by monogenean was highestin fish culture (29.5%) than that from drainage (20.4%) and River Nile branch (21.5%). The percentage ofinfection by protozoa was highest in fish culture (38.0%) and lowest in River Nile (8.5%). In the case ofmetacercarial infection, fish of the River Nile showed the highest prevalence (31.5%). Ectoparasites recoveredfrom examined fish were; protozoan parasites (Trichodina heterodentata; Trichodinella epizootica) and(Myxobolus tilapiae); two monogenean parasites (Dactylogyrus extensus and Cichlidogyrus tilapiae) andCentrocestus formosanus with different types of encysted metacercaria (Heterophydiae; Clinostomatidae).Hyperplasia was a common histological finding on the gills of fishes infested by monogenean and protozoanparasites. The infested fishes suffer from gills degeneration, necrotic changes and desquamation of therespiratory epithelium lining the gills secondary lamella.

[学科分类] 工程和技术（综合）

[关键词] Ectoparasites;monogenea;metacercariae;hyperplasia