LEUKOCYTE NUMBERS AND PHAGOCYTIC-ACTIVITY IN TURBOT SCOPHTHALMUS-MAXIMUS FOLLOWING IMMUNIZATION WITH VIBRIO-DAMSELA AND PASTEURELLA-PISCICIDA O-ANTIGEN BACTERINS

The effects of 2 injected bacterins, Vibrio damsela and Pasteurella pi scicida O-antigen bacterins, on the cell type composition of the perip heral blood and head kidney and on the phagocytic activity of the head kidney leucocytes were studied in turbot Scophthalmus maximus L. Bloo d and head kidney samples were collected from treated and non-treated turbot at different times in the 168 h period after injection. The num ber of neutrophils increased markedly in the peripheral blood of P. pi scicida O-antigen injected turbot 24 h after injection, being signific antly higher (p < 0.01) than the neutrophil number in V. damsela O-ant igen injected turbot. Forty-eight hours after injection, the numbers o f head kidney neutrophils and macrophages in V. damsela and in P. pisc icida O-antigen injected turbot increased significantly (p < 0.05) com pared with those in saline-injected turbot while the neutrophils in th e peripheral blood decreased in fish treated with each of the vaccines . Turbot neutrophils have peroxidase-positive granules and also showed phagocytic capability. The phagocytic rate of the peripheral blood an d head kidney phagocytes was higher in turbot injected with bacterins than in the saline-injected turbot, with the maximum phagocytic activi ty occurring 48 h after injection. Phagocytic activity of phagocytes i n peripheral blood, kidney, and spleen was equal. Our data show that t he phagocytes of turbot have a low phagocytic affinity for sheep red b lood cells in comparison to what has been reported for rainbow trout. Both V. damsela and P. piscicida O-antigen elicited a similar level of a non-specific immune response.