Evaluation of the efficacies of selected antibiotics and medicinal plants on common bacterial fish pathogens

Abstract

An experiment was conducted to compare the efficacies of some selected antibiotics and medicinal plants against common bacterial fish pathogens viz., Aeromonas hydrophila, Pseudomonas fluorescens and Edwardsiella tarda. Four different antibiotics viz., CFCIN (ciprofloxacin), Renamycin (oxytetracycline), DT-10 (doxycicline) and Sulfatrim (sulphadiazine + trimethoprim) were exposed in different doses (100, 75, 50 and 25 ppm) to the culture of freshly isolated bacteria under the in vitro condition for sensitivity test and minimum inhibitory dose (MID) was determined. Based on in vitro results, antibiotics were applied to the experimental infection of Thai silver barb, Barbonymus gonionotus. CFCIN showed the best result with 100% recoveries of challenged fish in prolonged bath treatment. Medicinal plants were selected on the basis of previous studies. Crude extracts were prepared from various parts (leaves and bulb) of garlic, turmeric, akand and neem and four different doses were applied to the fresh culture of pathogenic isolates under the in-vitro condition to determine minimum inhibitory dose (MID). However, garlic offered the best result with 90.00 ± 2.89% recoveries of challenged fish in aquarium trial. Akand + neem, turmeric and akand showed moderate to weak recovery rates with the same dose. The present study thus showed that medicinal plants would be an effective control measure along with antibiotics against bacterial fish diseases. Keywords: Efficacy; Medicinal plants; Bacterial fish pathogens DOI: 10.3329/jbau.v7i1.4980 J. Bangladesh Agril. Univ. 7(1): 163-168, 2009