Thesis (Ph.D.) - Cairo University - Faculty of Veterinary Medicine - Department of Animal Diseases

In the present study, 360 cultured marine fishes (Dicentrarchus labrax, Sparus aurata, Mugil cephalus, Liza ramada, and Anguilla anguilla) were collected from three farms in Diba triangle, over different year seasons. Fish and water samples were collected. Examined fish showed restlessness, air gasping, scales detachment, excessive mucous, emaciation and off food. Pale gills, friable liver, gastrointestinal tract congestion were revealed. Total prevalence rate of Parasitic infestation was 65.3%. Six protozoan genera namley Trichodina (T. heterodentata and T. lepsii) , Epistylis, Amyloodinium ocellatum, Microsporidia, Apiosoma sp. and Ambiphrya ameiuri, three monogenean(Diplectanum, Pseudohaliotrema and Furnestinia echeneis ), one crustacea (Caligus minimus), unidentified digenetic metacercaria, three trematodes(Timoniella, Bucephalus minimus and Saccocoelium) and one nematode (Conteracecum larvae) were illustrated. The highest protozoan prevalace was in autamn and least in summer, while C. minimus and helminthes were highest in summer and least in winter. Water temperature and salinity were the most effective parameters influencing parasitic infestation. Histopathologically, infested fishes showed different degrees of fusion in gill lamellae. Encysted metacercaria were revealed in intestine, muscle bundles, kidneys and spleen with inflammatory cells infiltrations

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