Induction of clinical aspergillomycosis by feeding contaminated diet to tilapia, Oreochromis niloticus (L.)

Abstract. Oreochromis niloticus maintained at 17°C and 26°C were fed a pelleted diet contaminated with cultures of Aspergitlus flavus fungus. Affected fish stopped feeding within one week, and became inactive, dark and oedematous. Exophthalmia, often accompanied by corneal or humoral changes, was common and mortalities commenced after 4 weeks. Surviving fish were sacrificed after 5 weeks and the fungus was isolated from all organs, including—irregularly—the eye. The histopathology was predominantly that of a necrotizing septicaemia, with fungal hyphae present in liver, peritoneum, kidney, intestinal wall and, distinctively, in the orbit and eye of affected fish.