Isolation and identification of fungi from apparently healthy and diseased Clarias gariepinus from freshwater in Zaria, Kaduna State, Nigeria

Abstract

Fish and fishery products have been documented as a major source of food-borne pathogens of which bacteria and fungi play major roles. The fungal organisms contaminating apparently healthy and diseased Clarias gariepinus in Zaria, Kaduna State was investigated. The standard mycological procedure revealed isolation of similar fungal organism been associated with apparently and diseased fish. The fungal organism isolated from the skin and gills of diseased fish were 26 (13.1%) Aspergillus fumigatus, 25 (12.6%) A. flavus, 36 (18.1%) Aspergillus niger, 37 (18.7%) Penicillium species, 14 (7.1%) Mucor species, 4 (2.0%) for Rhizopus species, 14 (7.1%) Trichophyton sp., and 42 (21.2%) yeast isolates. While the gills and the skin of apparently healthy C. gariepinus yielded 73 (18.6%) Aspergillus fumigatus, 53 (13.5%) A. flavus, 57 (14.5%) A. niger, 1 (0.25%) A. parasiticus, 45 (11.55%) Penicillium sp., 38 (9.7%) Mucor species, 6 (1.5%) Rhizopus sp. and 119 (30.4%) yeast. There was no statically significant (P > 0.05) difference in isolates from skin and gills. All the fish were positive for multiple fungal isolates. The diseased C. gariepinus were characterised wih skin ulcer, fin rot and tail rot. The study showed the majority of the isolates belonging to Aspergillus sp. and potential aflatoxin producers. Isolation of pathogenic fungi from skin and gills of C. gariepinus from cultures, meant for human consumption is alarming which can be a source of fish born infections. Attention should be paid to fish health in the culture so as to conserve public health and safeguard the farmer's investment.

Keywords: Clarias gariepinus, diseased, apparently healthy, fish, yeast and filamentous fungi.