Identification and protease activity of opportunistic pathogenic fungi in giant gourami (Osphronemus goramy)

Giant gourami (Osphronemus goramy) is a freshwater fish originating from Indonesia and spread in Southeast Asian countries, such as Malaysia. O. goramy is a broadly cultivated species that is sold and consumed in Malaysia, with a high economic value. Efforts to increase O. goramy cultivation have led to the emergence of various pathogenic microorganisms, such as fungi. Fungal infections occur when O. goramy are under certain conditions, so that the fungus is an opportunistic pathogen. The protease enzyme activity test was carried out to determine the proteolytic activity of opportunistic fungal pathogens isolated in O. goramy. The study aimed to determine the species and proteolytic activity of opportunistic pathogenic fungal targets in O. goramy from the Kampung Gong Badak Fish Market, Kuala Terengganu, Malaysia. The method used in the study was a survey through direct sample collection at the location, carried out by a purposive sampling method. The sample was a healthy O. goramy. Fungal identification was performed by macroscopic (visually) and microscopic methods. The protease enzyme activity test was carried out qualitatively by inoculating the fungus on PDA and skim milk media using a sterile toothpick. The results showed that there were seven species of opportunistic pathogenic fungi that were isolated from the gill and kidneys of O. goramy. Based on the seven species obtained, three species remained unidentified and four other species were identified as Exophiala sp., Acremonium sp., Saccharomyces sp. and Penicillium kewense. Two types of fungus, Acremonium sp. and P. kewense, showed protease enzyme activity, with a protein hydrolysis index of 1.44 and 1.50, respectively.