Pathological findings of Streptococcus agalactiae infection in saltwater tilapia (Oreochromis sp.)

Mustapa., Muhammad Zulhusni (2020) Pathological findings of Streptococcus agalactiae infection in saltwater tilapia (Oreochromis sp.). [Project Paper] (Submitted)

Text lp FPV 2020 54.pdf Download (6MB)

Abstract

This study was designed to evaluate the pathological changes in the brain, kidney, liver, spleen and eyes of saltwater Red hybrid tilapia (Oreochromis sp.) challenged with Streptococcus agalactiae. 30 saltwater tilapia fingerlings were divided into 3 groups; A (acute), B (chronic) and C (control). Both Groups A and B were inoculated intraperitoneally with 108 CFU/mL of S. agalactiae and monitor for 24-hours and a week respectively while Group C has remained as the negative control. Sampling was done in every 8 hours in 24 hours for Group A and 7 days post-infection for Group B. The clinical signs were recorded, and the collected samples were subjected to bacteria isolation, histopathology, immunohistochemistry (IHC) and polymerase chain reaction (PCR) to identify the antigen presentation. The clinical sign observed from both groups were anorexia, limited movement with resting at the base of the tank and present of elongated faeces attached to the anus. Besides, the chronic group showed imbalanced posture while swimming and moribund of 4 fish throughout the experiment. Macroscopically, both groups developed congestion in the spleen and gills with some fish having pectoral fins haemorrhages. Potbellies also present but more consistency in the chronic group. The histopathological finding recorded were congestion, infiltration of inflammatory cell and oedema in all the samples with more prominent in group B. The PCR and bacteria isolation have confirmed the existence of the bacterium in Groups A and B. IHC also showing positive result in both groups but the more intense reaction in Group B. In conclusion, the severity of the disease was affected by the duration of the infection and virulence of the organism.

Item Type:	Project Paper
Faculty:	Faculty of Veterinary Medicine
Depositing User:	Ms Nurhaznita Mahmood
Date Deposited:	23 Oct 2023 07:17
Last Modified:	23 Oct 2023 07:17
URI:	http://psaspb.upm.edu.my/id/eprint/1513

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