Ardiansyah, Amrullah, Dahlia, Indrayani, Ifan Dwinhoven
The mucus secreted in the epidermis of fish skin acts as the first line of defense between fish and pathogens in their living environment. Fish epidermal mucus has been reported to prevent the colonization of pathogenic bacteria. The study aimed to evaluate the activity of several immune-related enzymes (lysozyme and alkaline phosphatase) as well as the bacterial activity of the epidermal mucus of three types of freshwater fish; tilapia (Oreochromis niloticus), snakehead fish (Channa striata), and local catfish (Clarias batrachus) (against shrimp pathogenic Vibrio harveyi, V. parahaemolyticus, and V. alginolyticus). Crude and acidic extracts of epidermal mucus of fish were prepared and their antibacterial activity was tested by disc diffusion method against three bacterial pathogens of vannamei shrimp (Litopenaeus vannamei); Vibrio harveyi, V. parahaemolyticus, and V. alginolyticus, which were then compared with the antibiotic Streptomycin as a positive control and acetic acid as a negative control. Of the 18 tests performed (six types of epidermal mucus extracts against three different bacterial strains), 11 tests showed antibacterial activity. Acid-extracted epidermal mucus showed the strongest inhibitory potential against pathogenic bacteria V. harveyi, V. parahaemolyticus, and V. alginolyticus compared to crude extract. The acidic and crude extracts were further tested for lysozyme activity, and the results showed that the acidic extracts of O. niloticus had the highest level of lysozyme activity followed by the crude extract of C. bathracus and O. niloticus. In contrast, crude extract of C. striatus showed the highest level of alkaline phosphatase activity, but no differences were found among the extracts examined. Thin layer chromatography of all extracts showed violet with ninhydrin test and yellowish-brown spots with sulphuric acid, that’s indicating the presence of peptides and steroids respectively. Epidermal mucus contains some immune components that can help overcome the problem of antibiotic resistance of many pathogenic bacteria in shrimp culture. © 2022, BIOFLUX SRL. All rights reserved.
Fish Hatchery Technology Study Program, Department of Aquaculture, Pangkep State Polytechnic of Agriculture, Poros Makassar -Pare Pare Km 83 Mandalle, Pangkep Regency, South Sulawesi, 90655, Indonesia; Agricultural Technology Education Study Program, Faculty of Engineering, Makassar State University, South Sulawesi, Makassar, Indonesia
