Examination of naturally infected cultured Oreochromis niloticus which suffered from exophthalmia, eye cloudiness, dark pigmentation, ascitis, frayed fins and ulceration on the dorsal surface of the fish revealed mixed infection with the bacterium Pseudomonas putida and external parasitic protozoa. Parasitism with Trichodina, Chilodonella, Microsporidia and Epistylis species were detected. In parasitized fish lesions were observed in gills and skin. The rate of infestation with Trichodina, Chilodonella, Microsporidia and Epistylis species were 60%, 30%, 40%, and 50%, respectively. The total prevalence of P. putida infection among the examined fish in earthen ponds was 36%, while it was 40% in concrete ponds. The rate of isolation of P. putida from liver, kidneys, muscle lesions, spleen, and ascetic fluid of naturally infected fish were 30%, 21%, 17%, 11%, and 14%, respectively. Isolated P. putida had intrinsically resistant to chloramphenicol, ampicillin, tetracycline, neomycin, colistin sulphate, nitrofurantin, and naladixic acid. Histopathological changes in naturally and experimentally infected fish with P. putida and external parasites were studied.
Key words: Protozoa, pseudomonas putida infection, Oreochromis niloticus
|
