Virulence of Aeromonas hydrophila in Siamese fighting fish (Betta splendens) and the bacterium susceptibility to some herbal plants

Aeromonas hydrophila was isolated from diseased Siamese fighting fish Betta splendens Regans.  The virulence of A. hydrophiala to Siamese fighting fish was conducted by intraperitoneal injection of two doses of bacterial suspensions with ۷.۵×۱۰۷ and ۷.۵×۱۰۵ cfu per ۰.۰۵ ml. The cumulative mortality was observed in high and low dose groups which showed ۹۸.۳۳ and ۲۰ percent, respectively. Moreover, five medicinal plants extracts namely Centella asiatica, Morinda citrifolia, Melissa officinalis, Piper sarmentosum and Terminalia catappa were determined for antimicrobial activities by broth dilution method. Terminalia catappa extract showed highest antimicrobial effect of MIC and MBC (۲۵ and ۱۲.۵ mg mL-۱), followed by M. officinalis and P. sarmentosum with the same values of MIC and MBC (۱۲.۵ and ۲۵ mg mL-۱).  Finally, Centella asiatica and Morinda citrifolia were similarly MIC and MBC (۵۰ and ۱۰۰ mg mL-۱).  It was concluded that five medicinal plants can use to inhibit and kill A. hydrophila in fish.   

Keywords:

Aeromonas hydrophila , Betta splendens , Antibacterial activity , Medicinal plants