Mary Ghobrial
National Institute of Oceanography & Fisheries, Egypt
Title: Studies on the Bioactivity of Different Solvents Extracts of Selected Marine Macroalgae against Fish Pathogens
Biography
Biography: Mary Ghobrial
Abstract
Selected species of marine benthic algae belonging to the Phaeophyceae and Rhodophyceae, collected from different coastal areas of Alexandria (Egypt), were investigated for their antibacterial and antifungal activities against fish pathogens. In vitro screening of organic solvents extracts from the marine macroalgae, Laurencia pinnatifida (Hudson) Stackhouse, Pterocladia capillaceae (Gmelin), Halopteris scoparia (Linnaeus) Kutzing, Stepopodium zonale (J. V. Lamouroux) and Sargassum hystrix var. fluitans Borgesen, showed specific activity in inhibiting the growth of five virulent strains of bacteria pathogenic to fish Pseudomonas fluorescens, Aeromonas hydrophila, Vibrio anguillarum, V. tandara, Escherichia coli and of the two fungi Aspergillus flavus and A. niger. Acetone and ethanol extracts of all test macroalgae exhibited antibacterial activitiy, while acetone extract of S. hystrix exhibited the highest antifungal activity. Macroalgal extracts inhibited bacteria more readily than fungi, besides, the extracts of the Rhodophyceae species showed the greatest activity against current test bacteria rather than fungi. Cluster analysis revealed the general response of the tested pathogens to the action of the different algal extracts. Composition of the most potent algal extracts included acetone extracts of L. pinnatifida, P. capillaceae and S. hystrix and also, ethanol extract of P. capillacae was determined using GC-MS. The present study provides the potential of red and brown macoalgae extracts for the development of anti-pathogenic agents for use in fish aquaculture.