Determination of antimicrobial effect of Nannochloropsis sp. against some fish pathogenes

Microalgae Nannochlopsis sp., which are important photosynthetic organisms of aquatic ecosystems, are the primary sources of many bioactive compounds such as proteins, carbohydrates, lipids, vitamins and enzymes that can be used as antimicrobial and antiviral agents. These organisms are nowadays used directly in the food, cosmetic and pharmaceutical industry, or in aquaculture sector and biotechnological approach like biofuel or drug therapy. Finding the effective, environmental friendly chemotropic agents to control fish pathogens are crucial in a country like Turkey which has production capacity of about 240 thousand tons of cultured fish which is the second biggest producer in Europe. In our study, we tested the antimicrobial activity of Nannochloropsis sp. against some fish pathogens Aeromonas sp. that are major pathogens for rainbow trout farms. Agar disk diffusion test method was used for studying antimicrobial activity on pathogens. Aeromonas spp. have shown antimicrobial activity positively as the inhibition zones were 11,4-14,6 mm respectively. According to our primary results, we could use this organisms to control of fish disases as alternative reagents to antibiotics. KEYWORDS: Antimicrobial test, Fish diseases, Nannochloropsis