CAUSES OF EYE AFFECTION IN CAGED CULTURED NILE TILAPIA (OREOCHROMIS NILOTICUS) IN DAMIETTA GOVERNORATE, EGYPT.

CAUSES OF EYE AFFECTION IN CAGED CULTURED NILE TILAPIA (OREOCHROMIS NILOTICUS) IN DAMIETTA GOVERNORATE, EGYPT.

Abou El-Atta, M. E. and Walaa T. El-Ekiaby

Fish Health and Management Department, Central Laboratory for Aquaculture Research, Agricultural Research Center, Egypt.

Abstract

The present study was carried out on two hundred and fifty naturally diseased male monosex Nile tilapia (Oreochromis niloticus) with an average 130 ± 5
gm body weight collected from floating cages in El-Bostan Damietta Governorate. The collected fish submitted to full clinical, postmortem, bacteriological, mycological, parasitological and histopathological examination. In addition, some water quality analysis was measured. Clinical signs were random swimming near to water surface, sluggish movement, exophthalmia, general darking of body color, hemorrhage around the head, ventral aspect of the body, tail rot, parasitic eye cataract which appear as white dots, blindness, eye rupture outside (unilateral or bilateral), emaciation, appearance of cotton-like tufts on eye, skin and behind the head, as well as the post mortem finding were congested gills, liver, kidney, spleen and appearance of white caseated material around the heart. Gall bladders distended with bile and hemorrhagic intestine free from any food particles. In chronic cases with eye cataract and ruptured eye showed, pale gills, grayish liver with normal size, pale kidney and spleen and internal organs were anemic. The bacteriological investigation revealed the isolation of Aeromonas hydrophila and Pseudomonas fluorescens with prevalence 46.12% and 28.6% respectively. From the macroscopic and microscopic examination of isolated fungi, it was cleared that the isolated fungi was Saprolegnia parasitica with prevalence 25.25%. The parasitological examination of eye lens revealed infestation with the metacercarae Diplostomum sp. with infestation rate 25%. The antibiogram sensitivity test of isolated bacterial strains were done and showed that, A. hydrophila and P. fluorescens were sensitive to florefenicl, ciprofloxacin, nalidixic acid and tetracycline and resistant to ampicillin. Prevention and control trails were performed.