Stability of haematological parameters in stored blood samples of rainbow trout Oncorhynchus mykiss (Walbaum, 1792)

The aim of this study was to investigate the influence of storage time at +4 °C on haematological indicators in rainbow trout Oncorhynchus mykiss (Walbaum, 1792). For this purpose, 60 Italian trout were evaluated and red blood cells, white blood cells, thrombocyte count, haematocrit, haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration were determined. After blood collection (T0), all samples were immediately analysed using an automatic method to assess the haematological parameters and then divided into two different aliquots and stored at +4 °C. The first aliquot was refrigerated for 168 h (T1), the second one for 336 h (T2). Statistical analysis (one-way repeated-measures ANOVA) showed a significant effect of storage time (P < 0.05) on red blood cells, thrombocyte count, haematocrit, haemoglobin concentration, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration. The obtained data expand our knowledge of haematological evaluation techniques and could contribute to the development of an appropriate method for haematological analysis that is suitable for the evaluation of the health status of wild and farmed fish.