Some investigations on a chronic eye affection syndrome associated with extended mortality in an intensive fish farm [electronic resource].

Includes references.

This study conducted toward a problem of extended mortality and chronic eye affection in an intensive Oreochromus niloticus farm in Egypt. External examination of fish revealed that the affected fish was sluggish in movement, some with haemorrhagic eyes, others with uni or bilateral exophthalmia or excavated eyes. Also the eyes of some fish are covered by whitish membrane. The internal examination of fish showed no characteristic lesions. Bacterial isolation from the internal organs (liver, kidney and spleen) were negative for specific fish pathogens. Samples from the ration were analyzed for their chemical composition and the results revealed that the ration covered the requirement of Oreochromus niloticus. The results of water analysis showed that the level of unionized ammonia (1.77 mg/L) was far away from the maximum accepted level (0.02mg/L) which could be responsible for this problem.

Summary in Arabic.