摘要
Labroides dimidiatus has been proven to remove ectoparasites and monogeneans from client fishes and studies showed that they were not infected with the parasite. Due to this, there is a possibility that a defense mechanism against pathogen and parasitic invasion exist in the epidermal mucus which serves as a mechanical as well as biochemical barrier. The study was performed to identify the amino acid and fatty acid components using GC （gas chromatography） and HPLC （high performance liquid chromatography） in epidermal mucus ofL. dimidiatus. The present study revealed 16 components of amino acid and 22 types of fatty acid in epidermal mucus ofL. dimidiatzts. Linoleic acid （C18：2n6c） was the most prominent PUFA （polyunsaturated fatty acid） which contributed approximately 11.69% of total fatty acids. The other major fatty acids are palmitic acid （C 16：0）, oleic acid （C 18： l n9c）, linoledaidic acid （C18：2n6t）, arachidic acid （C20：0）, Gamma-Linoleic acid （C18：3n6） and gadoleic acid （C20：1） which contained reasonable amounts of 9.52%, 8.06%, 6.26%, 8.33%, 6.21% and 9.05% of total fatty acids, respectively. This present study also demonstrated the presence of various amino acids in skin extract. Glycine, glutamine, arginine, asparagin and alanine were found at high concentration of 8.09%, 6.95%, 5.73%, 4.74%, 4.58% respectively. The most abundance percentage of linoleic acid （C18：2n6c） was found to be the metabolic precursor of arachidonic acid （AA） which inducing platelet aggregation, facilitate the blood clotting process and adhesion in endothelial cells during wound healing and might be responsible for rapid tissue growth in L. dimidiatus. It can be concluded that the amino acid and fatty acid profile from the epidermal mucus ofL. dimidiatus contains most of the essential components required to play a possible role in its defense mechanism. Understanding the biochemical properties of L. dimidiatus epidermal mucus in defense mechanism would enable to determine how this fish protect itself from parasitic infection.
