Development and immunocompetence of juvenile flounder Platichthys flesus, L

• Published in: Fish & shellfish immunology Vol. 4; no. 1; pp. 63 - 78
• Main Authors: Pulsford, A., Tomlinson, M.G., Lemaire-Gony, S., Glynn, P.J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 1994
• Subjects: Brackish; flounder, juvenile, development, immunocompetence; Platichthys flesus; ANE, British Isles, England, Tamar Estuary; flounder, juvenile, development, immunocompetence
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1006/fsim.1994.1006

The development and immunocompetence of O group flounder Platichthys flesus from the Tamar estuary, Devon, was studied during the summer months of 1990. Fish maintained in laboratory aquaria were observed to grow more slowly than those collected at intervals from the river. Histological and ultrastructural studies showed the spleen contained mainly erythrocytes and the kidney mainly blast cells in the 10 mm fish. Mature erythrocytes, granulocytes, phagocytes, lymphocytes and thrombocytes were identified in the spleen and kidney of 15 mm fish. No thymic tissue was identified at either of these stages. The peripheral blood contained mainly erythrocytes with few lymphocytes and granulocytes. Assays for immunocompetence were applied to the juvenile fish. Phagocytosis of 35-50% of adherent spleen cells in fish of 4 cm was comparable with adult fish, but only 2-10% in fish less than 2·5 cm. Hydrogen peroxide secretion during the respiratory burst by spleen and kidney cells from juvenile fish (6·.2-7·3 cm) demonstrated maximum activity at 40 min after stimulation with zymosan. Greater amounts (1·3 nmol μg 1 cell protein) were secreted by the spleen macrophages than kidney macrophages (0·78 nmol μg 1 cell protein). Immunoglobulin molecules were detected in all serum samples of fish (6·2-7·3 cm) examined by Western blotting. Juvenile fish exposed to fluoranthene in laboratory aquaria did not show significant differences in in vitro phagocytic activity but exhibited nervous behaviour and 'loop-the-loop' swimming.