Iraqi Journal of Veterinary Sciences

Abstract

Bacteria pathogens may cause a serious loss in aquaculture and also health hazards to humans. On the basis of biochemical characteristics and API-20E system, all isolates of pathogens from diseased fish were identified as Aeromonas spp, the most predominant bacterial species were A. sobria 46.7%, A. caviae 19.03%, A. jandaei 8.6 % and A. veronii 8.6 %. One hundred and twenty Nile catfish Clarias gariepinus were divided into four equal groups (1,2,3 and 4) were challenged with Aeromonas sobria which predominant isolates, Gp. (1) was challenged only, while Gps. (2, 3 and 4) were treated after challenged with ciprofloxacin, clove extract and ciprofloxacin and clove extract in combination, respectively. The antibacterial activity of antibiotic and clove extract in their therapeutic doses decrease the mortality rate as (20, 16 and 13%) respectively compared with non-medicated Gp. (1) which recorded mortality 83%. Internal signs of infection with Aeromonas sobria in African catfish (Clarias gariepinus) include congestion of the hepatic blood vessels, areas of coagulative necrosis in the liver and hydropic degeneration of renal tubules according to the histopathological examination. In-vivo the combination of ciprofloxacin and clove extract was the choice as alternative bacterial therapeutic agent in infected Clarias gariepinus with Aeromonas sobria. Moreover histopathological changes have been widely used as biomarkers in the evaluation of the health of fish exposed to contaminants.