FATTY ACID IN ECTOPARASITE COPEPODS FROM SOUTHERN CHILE CALIGUS ROGERCRESSEYI BOXSHALL & BRAVO 2000, LEPEOPHTHEIRUS MUGILOIDIS VILLALBA & DURAN 1985 AND THE FREE-LIVING SPECIES TIGRIOPUS SP

This work presents the fatty acid composition of copepod species in southern Chile: two of them that are ectoparasites on Eleginops maclovinus (Caligus rogercresseyi and Lepeophtheirus mugiloidis) and one free-living species (Tigriopus sp.). C. rogercresseyi females from different hosts (Salmo salar and E. Maclovinus). Fatty acid methyl esters were determined with GC-MS. The studied species presented a wide variety of saturated, mono unsaturated, and polyunsaturated fatty acids, with compounds having from 12 to 24 carbons. The studied species had different percentage compositions of the acids identified. In all three species, palmitic (C-16) and oleic (C-18:1) fatty acids dominated the percentage concentrations. The highest percentage concentration (46.59%) was found for palmitic acid in Tigriopus. Only the females of C. rogercresseyi analyzed were found to have myristoleic acid (C-14:1). Stearic (C-18) and oleic (C-18:1) acids were present in both C. rogercresseyi males and females, but with different distributions. Oleic acid in females was 33.97% and only 7.64% in males, whereas stearic acid was 9.95% in females and 21.51% in males. The C. rogercresseyi on Patagonian blennie (Eleginops maclovinus) revealed 3.89% C-20:4 and 9.60% C-20:5. Eicosapentaenoic and docosahexaenoic acids, detected only in the ectoparasitic copepods, had percentage concentrations of up to 10%. The possible role of this fatty acid in the stimulation of innate fish immunity is discussed.