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Role of heat stress in red tilapia streptococcosis

Streptococcus agalactiae is one of the causative agents associated with warm-water streptococcosis that produces massive mortality in aquaculture. The emergence of disease in tilapia farms usually occurs during high temperature seasons, which suggested higher susceptibility of tilapia to infection u...

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Main Authors: Nazrin, Jahwarhar, Mohd Yusoff, Md Sabri, Omar, Noraini
Format: Conference or Workshop Item
Language:English
Published: 2012
Online Access:http://psasir.upm.edu.my/id/eprint/26805/1/PROCEEDING%2030.pdf
http://psasir.upm.edu.my/id/eprint/26805/
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spelling my.upm.eprints.268052016-08-01T03:55:58Z http://psasir.upm.edu.my/id/eprint/26805/ Role of heat stress in red tilapia streptococcosis Nazrin, Jahwarhar Mohd Yusoff, Md Sabri Omar, Noraini Streptococcus agalactiae is one of the causative agents associated with warm-water streptococcosis that produces massive mortality in aquaculture. The emergence of disease in tilapia farms usually occurs during high temperature seasons, which suggested higher susceptibility of tilapia to infection under this condition. Thus, the objectives of this study were to determine the pathogenesis of streptococcosis in heat-stressed tilapia using various routes of infection and the role heat stress in the development of streptococcal infection in tilapia. Red tilapias, including the control group without heat stress, were inoculated with 109 CFU/mL of S. agalactiae via intraperitoneal, immersion and immersion cut routes of inoculations and maintained at a water temperature of 34ºC for 24 hours. Samples of brain, eyes and kidneys were taken and subjected to bacterial isolation, PCR, histological examination and immunoperoxidase test. Diseased fish showed typical signs of bacterial septicaemia including skin and fin haemorrhage and exophthalmia. The fishes were more susceptible to intraperitoneal route of infection, followed by immersion cut and lastly immersion. The bacteria was isolated and detected by PCR from all organs of fishes with and without heat stress. The lesions were more clearly seen first in fishes with heat-stressed than those without. Fifty percent mortality occurred in the heat-stressed group infected via intraperitoneal route. However, no mortality was observed in the group without heat stress. Post-mortem revealed that the lesions were more severe in the heat-stressed group infected via the intraperitoneal route than those infected via the immersion cut and immersion routes. The lesions observed were haemorrhage, presence of inflammatory cells and bacteria in the brain, eyes and kidneys. There is significant (p<0.05) difference between route of infection and heat stress in most of the organs. However there is no significant (p>0.05) difference was observed between routes of infection in most organs of fishes without heat stress. Immunoperoxidase test were positive in most organs. However, the intensity of the antigen-antibody reactions were greatest in the group infected via the intraperitoneal route followed by immersion cut and immersion groups. In conclusion, the severity of lesions observed in the brain, eye and kidneys are most marked in heat-stressed red tilapias infected with S. agalactiae via the intraperitoneal route, followed by the immersion cut and lastly the immersion route. 2012 Conference or Workshop Item PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/26805/1/PROCEEDING%2030.pdf Nazrin, Jahwarhar and Mohd Yusoff, Md Sabri and Omar, Noraini (2012) Role of heat stress in red tilapia streptococcosis. In: 7th Seminar in Veterinary Sciences, 27 Feb.-2 Mar. 2012, Faculty of Veterinary Medicine, Universiti Putra Malaysia. .
institution Universiti Putra Malaysia
building UPM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Putra Malaysia
content_source UPM Institutional Repository
url_provider http://psasir.upm.edu.my/
language English
description Streptococcus agalactiae is one of the causative agents associated with warm-water streptococcosis that produces massive mortality in aquaculture. The emergence of disease in tilapia farms usually occurs during high temperature seasons, which suggested higher susceptibility of tilapia to infection under this condition. Thus, the objectives of this study were to determine the pathogenesis of streptococcosis in heat-stressed tilapia using various routes of infection and the role heat stress in the development of streptococcal infection in tilapia. Red tilapias, including the control group without heat stress, were inoculated with 109 CFU/mL of S. agalactiae via intraperitoneal, immersion and immersion cut routes of inoculations and maintained at a water temperature of 34ºC for 24 hours. Samples of brain, eyes and kidneys were taken and subjected to bacterial isolation, PCR, histological examination and immunoperoxidase test. Diseased fish showed typical signs of bacterial septicaemia including skin and fin haemorrhage and exophthalmia. The fishes were more susceptible to intraperitoneal route of infection, followed by immersion cut and lastly immersion. The bacteria was isolated and detected by PCR from all organs of fishes with and without heat stress. The lesions were more clearly seen first in fishes with heat-stressed than those without. Fifty percent mortality occurred in the heat-stressed group infected via intraperitoneal route. However, no mortality was observed in the group without heat stress. Post-mortem revealed that the lesions were more severe in the heat-stressed group infected via the intraperitoneal route than those infected via the immersion cut and immersion routes. The lesions observed were haemorrhage, presence of inflammatory cells and bacteria in the brain, eyes and kidneys. There is significant (p<0.05) difference between route of infection and heat stress in most of the organs. However there is no significant (p>0.05) difference was observed between routes of infection in most organs of fishes without heat stress. Immunoperoxidase test were positive in most organs. However, the intensity of the antigen-antibody reactions were greatest in the group infected via the intraperitoneal route followed by immersion cut and immersion groups. In conclusion, the severity of lesions observed in the brain, eye and kidneys are most marked in heat-stressed red tilapias infected with S. agalactiae via the intraperitoneal route, followed by the immersion cut and lastly the immersion route.
format Conference or Workshop Item
author Nazrin, Jahwarhar
Mohd Yusoff, Md Sabri
Omar, Noraini
spellingShingle Nazrin, Jahwarhar
Mohd Yusoff, Md Sabri
Omar, Noraini
Role of heat stress in red tilapia streptococcosis
author_facet Nazrin, Jahwarhar
Mohd Yusoff, Md Sabri
Omar, Noraini
author_sort Nazrin, Jahwarhar
title Role of heat stress in red tilapia streptococcosis
title_short Role of heat stress in red tilapia streptococcosis
title_full Role of heat stress in red tilapia streptococcosis
title_fullStr Role of heat stress in red tilapia streptococcosis
title_full_unstemmed Role of heat stress in red tilapia streptococcosis
title_sort role of heat stress in red tilapia streptococcosis
publishDate 2012
url http://psasir.upm.edu.my/id/eprint/26805/1/PROCEEDING%2030.pdf
http://psasir.upm.edu.my/id/eprint/26805/
_version_ 1643829015726784512
score 13.211869

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