Advances in Animal and Veterinary Sciences

Research Article
Adv. Anim. Vet. Sci. 8(1): 77-88
Http://dx.doi.org/10.17582/journal.aavs/2020/8.1.77.88
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Gamal A. Younis1, Abo El Kheir M. Esawy2, Rasha M. Elkenany1*, Muhammad M. Shams El Deen3

1Department of Bacteriology, Mycology and Immunology, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt; 2Department of Bacteriology, Mycology and Immunology, Animal Health Institute El-Mansoura Branch, Mansoura 35516, Egypt; 3Veterinarian, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt.

Abstract | This study aimed to investigate fungi exist in the skin/fins, gills, and internal organs of two economically essential diseased fresh water fish species with amplification of Internal Transcribed Spacer (ITS1-ITS4) regions of ribosomal DNA as the reference method for Saprolegnia parasitica identification, in Egypt. Among 500 samples from Oreochromis niloticus and Clarias gariepinus, mycological investigations had revealed 148 (29.6%) fungal isolates with 6 genera: Aspergillus spp. (51.3%) with A. niger as the most dominant species, Saprolegnia spp (16.2%), Penicillum spp., Alternaria spp. (10.8% each), Cladosporium spp. and C. albicans (5.4%). Moreover, skin/fins (55.4%) was the most affected area followed by gills (18.9%) and internal organs (liver 10.8%, kidney 10.2%, eyes 2.7% and spleen 2%). The highest fungal infection rate was demonstrated during autumn (41.7%), followed by winter season (36%). The intraperitoneal-challenged C. gariepinus groups with A. flavus, C. albicans, A. niger and Cladosporium spp. displayed the highest cumulative mortality rate (100, 80, 70 and 70% respectively), while the intramuscular challenged C. gariepinus groups with A. flavus, A. niger and C. albicans revealed the highest mortality rate (60, 50 and 50% respectively). Furthermore, presumptive identification of the 24 isolates was initially suggestive of Saprolegnia species. Therefore, PCR assay joined with partial sequencing of ITS gene was confirmed the identification of 9 representative S. parasitica strains. This finding confirmed that the diseased fresh water fish species may harbor potential clinically applicable fungal species.

Keywords | Aspergillus spp., Clarias gariepinus, Fungi, Oreochromis niloticus, Sparolegnia parasitica.