The Inhibitory Effect of the Aqueous Extract of Ceratophyllum demersum on Vibrio cholarae that Isolated from Cyprinus carpio

The current study was conducted to determine the inhibitory effect of the aqueous extract of hornwort Ceratophyllum demersum on Vibrio cholerae bacteria that affects the common carp Cyprinus carpio L. in fish farms. The inhibitory effect of the aqueous extract was determined in petri dishes. The inhibition effects of the extract and six common antibiotics (Nalidixic acid, Nitrofurantoin, Gentamicin, Streptomycin, Tetracycline, and Amoxicillin) were compared; the results showed that the inhibition effect of the aqueous extract of hornwort was higher than the inhibitory effects of the six antibiotics. The stock solution 100% of the aqueous extract showed an inhibition effect reached 35.3 mm compared with 25 mm, 15 mm, 7 mm, 10 mm, 23 mm and 11 mm of Nalidixic acid, Nitrofurantoin, Gentamicin, Streptomycin, Tetracycline, and Amoxicillin antibiotics respectively. A positive correlation was recorded between concentration of aqueous extract and its inhibitory effect. The average of inhibition diameter was 23.3 mm, 27.6 mm, 28.6 mm, and 35.3 mm for the concentrations 25%, 50%, 75% and 100% of the stock solution, respectively.