Haematopoietic Potential of Tench (tinca Tinca) Pronephros in Relation to Ambient Temperature and Relative Condition Factor

The aim of this study was to detect the correlation between the change in the ambient temperature and adaptation of the pronephros – the main haematopoietic organ in fish, which so far has not been subject of research. Compared with other teleosts and their number of blood cells in peripheral blood, tench (Tinca tinca L. 1758) showed the corresponding trend of changes in number of pronephros haematopoietic cells after exposure to increased water temperature. The number of all haematopoietic cell lines was changed during the conditions of thermal stress (P<0.01; P<0.05). The number of erythroblasts was significantly reduced due to shift of haemoglobin curve of dissociation to the right. Leukopoietic cells were increased significantly as a response of pronephros to stress and all endocrine mediators of the stress (cortisol, leukine, etc.). The number of prothrombocytes was slightly decreased due to mobilisation into peripheral blood as in the case of cell precursor of monocytes. Eosinophilic and basophilic granuloblasts were not found in tench pronephros. Correlation (R) between body mass and total length was 0.526. Sex-specific variation of haematopoietic cells number in the same group was not observed (P>0.05), but it was significant between males or females among different groups (P<0.01; P<0.05 respectively).