ISOLATION AND CHARACTERIZATION OF FUNGI ASSOCIATED WITH BODY AND EGG FROM DISEASED AFRICAN CATFISH, Clarias gariepinus

Abstract

African catfish (Clarias gariepinus) are in high demand in the Malaysian market. However, these species are known to be easily infected with diseases such as fungi, which can cause mortality and economic losses. In addition, fungal infection in fish eggs can reduce their production. The objective of this study was to isolate and identify fungi from infected African catfish and their eggs. Symptoms include a swollen lesion, irregular swimming, darker discoloration, and screening of pathogenic fungi. Isolations, identifications, and extracellular enzymatic assays were performed for the isolated fungi. Potato dextrose agar was used as isolation medium for isolating fungi on African catfish and their eggs. Fungi were identified by macroscopic observation of growth morphology and their structure, followed by microscopic observation after staining with lactophenol cotton blue to observe hyphae. From the result, three fungi were isolated and identified as Mucor sp. (2n) and Trichoderma sp. (1n). All isolated fungi were also analyzed for extracellular enzymes such as proteases, amylases, and lipases to test their ability to produce them as pathogenic fungi. Trichoderma sp. showed positive results in all tests. However, one strain of Mucor sp. reacted positively to the amylase and lipase test, while the other strain of the same species showed no reaction, indicating a negative result. In conclusion, the isolated fungi have virulent properties and can cause mortality if the body and eggs are infected. Therefore, fish farms need comprehensive health management to prevent the spread of fungal diseases