No abstract

Hemolymph characteristics were examined in experimentally cultured blue mussels Mytilus galloprovincialis Lmk, from 2 locations in the Ria d e Vigo (NW Spain). The highest protein, lysozyrne and agglutinin values were found in July. The increase of agranular hemocytes and the decrease of granular blood cells in April was associated with parasitism by Mytilicola intestinalis. No linkage was found between the number of circulating hemocytes and hemolymph component (lysozyrne, agglutinins and proteins) concentrations with parasitism. It is suggested that the number of circulating hemocytes, lysozyme and proteins levels and agglutination titer were related to the reproductive cycle and varied according to the location of mussels.

No abstract

The development of turbot Scophthalmus maximus culture has resulted in an increase of pathological problems involving mainly bacterial infections. During 1990, mortalities were detected in some grow-out facilities in Galicia, Spain, and were attributed to the microsporidian Tetramicra brevifilum Matthews & Matthews, 1980. The outbreak lasted for 3Y2 mo. The start of the outbreak was associated with a drop in temperature. Affected fish showed an erratic swimming behaviour, swelling of different parts of the body, darkening of the dorsal surface, and overproduction of mucus on the surface of the body. Fish with a high intensity of infection had jelly-like muscles. Small xenomas formed by T brevifilum were found to be associated with regressive changes of the host tissue, with agglomerations of mature spores eliciting sometimes inflammatory reaction of the host. The agglutinin titers detected in naturally infected fish were low. There was a light host response. Electrophoresis of sera from naturally infected fish showed an additional protein band (molecular weight: 128 kDa) not found in uninfected samples. Results suggest that although turbot infected with microsporidians are immunologically impaired, the immunodepression does not increase the susceptibility of fish to vibriosis.

Yeast (Saccharomyces cerevisae) beta-1,3 glucans were used as adjuvant in a Vibrio damsela vaccine for turbot (Scophthalmus maximus L.). Turbot were injected with the adjuvant prior, at the same time and after the vaccine. Several immune parameters (index and rate of phagocytosis, passive haemolytic plaque numbers, and agglutinating antibody titers) were determined at different times postinoculation. The highest activity of all the immune parameters was obtained when glucans were injected after the bacterin. It is concluded that the sequence of glucan administration is critical when used as a vaccine adjuvant.