Histo-pathology of the Vibrio alginolyticus bacteria on tiger grouper (Epinephelus fuscoguttatus Forskal)

Abstract

The purpose of this study was to determine histo-pathology of bacterium V. alginolyticus against several tiger grouper fish organs. The pathogenicity test was carried out by injecting intramuscularly (IM) 0.1 ml of V. alginolyticus bacterial suspension with bacterial density of 107, 108, 109 cells/ml/fish and injected with 0.1 ml of PBS solution (phospate buffer solution) as a control. Results showed that bacterium V. alginolyticus causes degeneration, damage and structural changes in the tissues of gill organs, kidneys, liver, and brain of tiger grouper fish. Pathogenicity challenge tests also prove that this bacterium is a true pathogen for test animals. The degree of density of the suspension of pathogenic cells affects mortality and incubation period. The bacterial density of 107 cells/ml/fish has caused death of 33.33%, density of 108 cells/ml/fish causes’ death of 66.67%, and density of 109 cells/ml/fish causes death of 73.33%, while without bacteria (control) there is no death.