Analysis of Some Immune Parameters in The Skin Mucus of Four Cultured Fish Species

Abstract

The skin mucus layer and its components provide the first line of defense against fish pathogens. The skin mucus samples were taken from four species Nile tilapia (Oreochromis niloticus), rainbow trout (Oncorhynchus mykiss), Siberian sturgeon (Acipenser baerii), and the European sea bass (Dicentrarchus labrax) for analyzing of some immune parameters. It is measured the activities of alkaline phosphatase, lysozyme, myeloperoxidase, bactericidal activity (against Aeromonas hydrophila), total protein and immunoglobulin concentration. The sea bass had highest level of lysozyme, myeloperoxidase, and bactericidal activities, and so were the total protein and immunoglobulin concentrations. The alkaline phosphatase activity in skin mucus measured in Nile tilapia as maximum level while the immune activity observed in sea bass among fish species. The skin mucus determined a more robust bactericidal activity against A. hydrophila fish pathogen in all fish species. The current study results presented preliminary information for better comprehension of the function of skin mucus as a key component in the different fish immune systems in aquaculture.