Date Received: 28-04-2016 / Date Accepted: 06-06-2016
The use ofantibioticsfor treating fish diseases has severaladvantagesbutraises theconcerns about antibiotic residues in fisheryproductsand increasesantibiotic resistance of pathogenic bacteriaas well. Herbs have been increasingly demonstrated their important role in the pharmaceutical industry as a biosafety solution, an alternative to synthetic chemical drugs. The present study aimed to examine the efficiencyof leaf extraction fromPiper betleby five different solvents (distilled water,methanol 80%, ethanol 96%, n-hexan andaceton 100%), and evaluate the anti-bacterial effects of the extract on Aeromonasspp. and Streptococcus agalactiaewhich cause hemorrhagic disease in tilapia. The results showed that the extractionefficiency varied from 4,00% (n-hexan solvent) to 19,67% (ethanol 96% solvent). At the concentration of 100 mg/ml, all these extracts showed good antibacterial activity against Aeromonasspp. and Streptococcus agalactiae.For Aeromonasspp., the inhibition zone variedfrom 15,00 mm (distilled water solvent - DW) to 28,00 mm (ethanol 96% solvent). The inhibition zones of Streptococcus agalactiaewere variedfrom 17,67 mm (DW solvent) to 31,67 mm (ethanol 96% solvent). The ethanol-extract solution showed highestanti-bacterial effect. This extract remained the anti-bacterial activity to Aeromonasspp.and Streptococcus agalactiaeat concentration 0,39mg/ml and 0,78 mg/ml,respectively.
