~ 158 ~ International Journal of Fisheries and Aquatic Studies 2014; 2(2): 158-162 ISSN: 2347-5129 IJFAS 2014; 2(2): 158-162 © 2013 IJFAS www.fisheriesjournal.com Received: 06-10-2014 Accepted: 31-10-2014 Md. Manjurul Islam Department of Fisheries & Marine Bioscience, Jessore University of Science & Technology ( JUST) , Jessore-7408, Bangladesh. Md. Mer Mosharraf Hossain Department of Fisheries & Marine Bioscience, Jessore University of Science & Technology ( JUST) , Jessore-7408, Bangladesh. Md. Sherajul Islam Department of Fisheries & Marine Bioscience, Jessore University of Science & Technology ( JUST) , Jessore-7408, Bangladesh. Shoumo Khondoker Department of Fisheries & Marine Bioscience, Jessore University of Science & Technology ( JUST) , Jessore-7408, Bangladesh. Mst. Aisha Khatun Department of Fisheries & Marine Bioscience, Jessore University of Science & Technology ( JUST) , Jessore-7408, Bangladesh. Correspondence: Shoumo Khondoker Department of Fisheries & Marine Bioscience, Jessore University of Science & Technology (JUST), Jessore- 7408, Bangladesh. Competitive antibacterial activity of two Indian major carps and two Chinese carps fish mucus against common pathogenic bacteria at aquaculture pond Md. Manjurul Islam, Md. Mer Mosharraf Hossain, Md. Sherajul Islam, Shoumo Khondoker, Mst. Aisha Khatun Abstract A search for antibacterial activity of carp fish mucus was performed for different protein concentrations, against four different bacterial strains Aeromonas hydrophila, Aeromonas sorbia, Pseudomonas fluorescens and Vibrio anguillarum. Protein concentrations (3.40 mg/ml) in catla mucus samples were found higher than the protein concentrations (3.12 mg/ml) of rohu mucus samples when tested by Bicinchoninic assay (BCA). Antibacterial activity was detected in mucus samples of four carp fish species, against the four bacterial strains. The results of this study indicate that the mucus of carp fish contain one or several components (protein, beneficial bacteria and other chemical component) with antibacterial activity. These bioactive substances may play an important role in the ability of mucus to defend carp fish against pathogenic bacteria or microorganisms. However, more investigation is necessary to confirm the antibacterial activity in carp fish mucus at different protein concentration and to purify and characterize the active components. Keywords: Antibacterial activity, Protein concentration, Fish pathogens, Mucus. 1. Introduction Advanced improvements and new formulations in the modern chemotherapeutic techniques have been used widely. But infectious diseases are still an alarming issue in case of public health in recent world [1] . So, still new methods of extruding pathogens along with the combination of existing methods are desired [2] . To promote this state, in recent times, research has been introduced to find out a potential method to prevent diseases worldwide. Several endeavors have been made to discover novel antimicrobial drugs from natural sources together with plant and animal product [3] . Natural chemicals have been a boon for shielding and treating the various indisposition of diverse origin [4] . Using these chemicals in human chemotherapeutics is a common practice. WHO stated that, out of 252 traditional medicines, 8.7% and 11.1% come from animals and plants originated sources respectively [5] . Fish body also exerts such by products like potentially valuable enzymes, proteins, minerals, flavours or pigments which have a key role in their innate defense mechanisms [6] . Fish lives in aqueous environment which itself is a source of microbial pathogens invading aquatic organisms. Even with a close contact with high concentrations of such pathogens, fish can still preserve a fit and vigorous system under normal condition. The fish produces mucus substances composing of biochemically diverse secretions from epidermal and epithelial cells which are key components of innate immunity [7, 8] . The mucus layer thought to act as a lubricant [9] . This layer wraps the surface of external body to lessen body friction against water and to protect from detrision injury [10] and as a mechanical barrier of the skin it hinders way in the majority of microorganisms into the body. Fish biologists suspected that mucus might be involved in ion regulation [11] . Increased rate of susceptibility to bacterial infection in carp (Cyprinus carpio) was evidenced with the loss of epidermal mucus [12] . A certain fatty acid compositional study of the flesh of the snakehead (Channa striatus) revealed unusually high arachidonic acids actively involved in initiating wound repair [13] .