Abstract:
The objective of this study was to investigate the efficacy of guava (Psidium guajava L.) leave extracted with 95% ethanol against Aeromonas hydrophila in fancy carp (Cyprinus carpio). In this study, 46.17% total tannin in the 6.32% yield guava leaf was extracted. In vitro test showed that the MIC for A. hydrophila was 800 ppm concentration. For in vivo testing, the non-challenged and challenged fishes were treated by guava leaf extraction at 1,600 ppm via feeding and one-minute daily dipping for 20 days. The genotoxic, histopathological, hematological and blood biochemical values had no significant (p<0.05) difference between before and after treatments, but the phagocytic ability and the chemotaxic activity in orally fed group were significantly increased (p<0.05) (19.13% to 25.00% and 36.30% to 48.33%, respectively) in non-challenged group. In challenged group, the mortality rate in dipping group (43.3%) was lower than feeding group (70.0%) and compared to the control group (63.3%), and the mortality rate was higher than the enrofloxacin dipped group (26.6%) on the 20th day (P<0.05). The result, indicated that guava leave extract at 1,600 ppm given orally may have increased non specific-immunity in non-challenge group and the survival rate was increased significantly by dipping method in challenged group (p<0.05).