El Asely, A., Youssuf, H., Abdel Gawad, E., Elabd, H., Matter, A., Shaheen, A., Abbass, A. (2020). Insight into summer mortality syndrome in farmed Nile tilapia (Oreochromis niloticus) associated with bacterial infection.. test, 39(1), 111-118. doi: 10.21608/bvmj.2020.40404.1255
Amel M El Asely; Hadeer Youssuf; Eman Abdel Gawad; Hiam Elabd; Aya Matter; Adel Shaheen; Amany Abbass. "Insight into summer mortality syndrome in farmed Nile tilapia (Oreochromis niloticus) associated with bacterial infection.". test, 39, 1, 2020, 111-118. doi: 10.21608/bvmj.2020.40404.1255
El Asely, A., Youssuf, H., Abdel Gawad, E., Elabd, H., Matter, A., Shaheen, A., Abbass, A. (2020). 'Insight into summer mortality syndrome in farmed Nile tilapia (Oreochromis niloticus) associated with bacterial infection.', test, 39(1), pp. 111-118. doi: 10.21608/bvmj.2020.40404.1255
El Asely, A., Youssuf, H., Abdel Gawad, E., Elabd, H., Matter, A., Shaheen, A., Abbass, A. Insight into summer mortality syndrome in farmed Nile tilapia (Oreochromis niloticus) associated with bacterial infection.. test, 2020; 39(1): 111-118. doi: 10.21608/bvmj.2020.40404.1255

Insight into summer mortality syndrome in farmed Nile tilapia (Oreochromis niloticus) associated with bacterial infection.

Benha Veterinary Medical Journal
Article 22, Volume 39, Issue 1, September 2020, Pages 111-118    PDF (315.64 K)
Document Type: Original Article
DOI: 10.21608/bvmj.2020.40404.1255
Authors
Amel M El Asely* 1; Hadeer Youssuf2; Eman Abdel Gawad2; Hiam Elabd2; Aya Matter2; Adel Shaheen2; Amany Abbass2
1Department of Aquatic animals diseases and Management, Faculty of veterinary medicine, Benha university
2Department of Aquatic Animals Diseases and Management, Faculty of Veterinary Medicine, Benha University, Egypt
Abstract
The present study was carried out to determine the possible causes of summer mass mortalities among farmed Nile tilapia, Oreochromis niloticus. Pure bacterial colonies were isolated from moribund O. nitoticus from 13 different fish farms; which suffered from high mortalities ranged from (50-80%), during the period from April to October, 2018. Fish showed external hemorrhagic spots, skin darkening, abdominal distension and exophthalmia. Internally, congestion and enlargement of internal organs with serous or hemorrhagic fluid was the most obvious picture. Based on the phenotypic and biochemical characterization using API20E, the isolated bacteria were identified as (A. veronii, A. hydrophila, A. caviae and A. sobria; Aeromonads), (Ps. Fluorescence; Pseudomonas spp), (E. sakazakii and E. cloacae; Enterobacter spp), (C. freundii; Citrobacter spp), (S. odorifera, S. liquefaciens, and S. marcescens; Serratia spp), (S. lutiensis, S. equine; Streptococcus spp), Lactococcus lactis and Proteus vulgaris; with the most prevalence to Aeromonads. Most isolates were accurate identified by PCR and gene sequencing. Water physicochemical parameters were measured at the farm site; which showed an increase in the level of both pH and ammonia. In order to confirm the pathogenicity of the bacterial isolates, an experimental infection was conducted using different doses. The results revealed that A.veronii (HY2) at dose of 9×108 cells/ml was the most pathogenic , with mortality rate 100 %. This study concludes that A. veronii, C. freundii, P.vulgaris and P. fluorescens are implicated in summer mortality of Nile tilapia, without neglecting the role of water quality in worsening the problem.
Keywords
. niloticus; Mass moralities; Gene sequencing; bacterial infection
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