A Preliminary Study on the Effect of Saprolegnia ferax Infestation on the Gill Tissues of Tilapia Fingerlings

Abstract

The present study focuses on the effect of Saprolegnia ferax infestation on the gill tissues of tilapia (Oreochromis niloticus) fingerlings, specifically on the number and diameter of chloride cells. External symptoms of infestation that include presence of white patches in the fish body were also noted. Tilapia fingerlings were inoculated with 1 ml of 0%, 40% and 80% culture concentration of S. Serax in Potato ‘Dextrose Broth media. Gills were excised after 48 and 96 hours of exposure and processed for light microscopy. Chloride cell proliferation was observed on the fish gills from the 40% and 80% treatment groups. Chloride cell size ranging from 0.04 to 0.05 mm in diameter did not vary among the test groups. Epithelial lifting, lamellar hyperplasia and necrosis of epithelium were also observed on the gills of the fishes in the treatment groups. Absence of white patches on individual fish body can be attributed to the relatively short period of infestation.