Morphological and cytochemical studies on blood cells of fish in different habitats

Objective: In the present study, it was aimed to investigate the morphology and cytochemical properties of peripheral blood cells in sea bass and sea bream, which are saltwater fish, and rainbow trout, which is freshwater fish. Materials and Methods: In the study; blood samples taken from eight fish of each species, including sea bass, sea bream and rainbow trout, into tubes with heparin and EDTA were used as material. To the prepared smears; CR, PAS, SB, TB, MGG, MGP, ANAE and sABC staining methods were applied and light microscopic examination was performed. Results: Based on cytochemical results, blood cells were detected in all three fish species, similar to mammals and birds. There was no problem in the differentiation of erythrocyte, lymphocyte and thrombocyte. In terms of granulocytes, it was determined that the cells could be affected by the type of anticoagulant used before the cytochemical methods, and sometimes by the fixation process, depending on the fish species. The characteristics of CR, SB, PAS, TB, MGG, MGP positivity in granulocytes according to fish species and their response to anticoagulant were recorded. Enzymhistochemically, nonspecific esterase (ANAE) positivity was determined in lymphocytes, monocytes and granulocytes, although it varies according to fish species. In addition, T lymphocytes were detected immunohistochemically in sea bass using DLT15 monoclonal antibody. Conclusion: It has been concluded that different alternatives should be tried in the use of anticoagulants and the application of fixation while performing cytochemical studies in fish blood. It was thought that the morphological and cytochemical characteristics of the cells were caused by the taxonomic family difference rather than habitat differences. In the light of the information obtained in the presented study, the examination of the granule contents of granulocytes by enzymehistochemical methods, at the light and electron microscopic level will contribute to the learning of the evolutionary development of nonspecific and specific immunity. Keywords: Anticoagulant, Sea bream, Sea bass, Rainbow trout, Peripheral blood