IMMUNE CELLS IN THE LIVER OF MUGILID JUVE NILES (LIZA SP, MUGILIDAE, TELEOSTEI) - ULTRASTRUCTURAL APPROACH

An ultrastructural characterization of hepatic immune cells in mugilid juveniles (Liza sp.) was performed. The cytological study revealed sm all lymphocytes and cells belonging to the mononuclear phagocyte syste m (i. e. monocytes, macrophages, melano-macrophages). These immune cel ls exhibited a similar morphology to that of other chondrostean and te leostean species. The observations indicate that macrophages show the highest capacity of phagocytosis. Melano-macrophage centres (MMC) main ly consisted of macrophages containing degenerated debris of hepatocel lular origin (residual bodies with lipofuscins). Apparently the size a nd structure of hepatic MMC represent non-specific means of phagocytos is related to different physiological processes. The use of such crite ria, as indicators of health of grey mullet juveniles in the more cont aminated coastal environment, should be undertaken.