ISSN 2375-0715
African Journal of Fisheries Science ISSN: 2375-0715 Vol. 5 (6), pp. 260-266, September, 2017. © International Scholars Journals
Full Length Research Paper
Isolation of Edwardsiella tarda-like species and its frequency of occurrence in freshwater fish harvested for human consumption from Lake Hawassa and crater lakes around Bishoftu, Ethiopia
Nuredin Nemo1, Tesfaye Sisay2 and Takele Abayneh3
1Dodota Sire district Livestock and Fishery Resource Office, Arsi Zone, Oromia Region, Dhera, Ethiopia.
2Unit of Biotechnology, College of Computational and Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
3National Veterinary Institute, Bishoftu/Debre-zeit, Ethiopia.
Corresponding Author. E-mail:[email protected]; Tel: +251 911 407632
Accepted 01 August, 2017
Abstract
A study was conducted to isolate Edwardsiella tarda-like species from apparently healthy freshwater fish (African cat fish, Clarias gariepinus and Nile tilapia, Oreochromis niloticus) originating from Lake Hawassa and crater lakes around Bishoftu, Ethiopia and thereby determine its distribution. Standard bacteriological examination of tissue specimens (kidney, liver and intestine) aseptically collected from fish harvested for human consumption resulted in a total of 16 isolates (10 from intestine, 4 from liver and 2 from kidney) showing similar colony and biochemical characteristics to E.tarda and were presumptively identified as E.tarda-like species due to the difficulties in differentiating them from the phenotypically similar new taxa viz. E.piscicida and E.anguillarum. There was significant variation (P<0.05) in the chance of isolating the bacterium among the organs examined with the organism being most frequently isolated from the intestine. Of a total of 210 fish included in the study, the bacterium was isolated from 16 (7.6%) of them with significant difference (P<0.05) observed in its occurrence with respect to origin of fish host. The isolation of E.tarda-like species from apparently healthy fish in the current study indicates potential sources of disease epidemics in fish as well as safety concerns on local fish products consumed raw or improperly cooked.
Key words: African Catfish, Nile tilapia, Edwardsiella tarda, Ethiopia.