Temporal variations in haematological and biochemical indices of the Caspian kutum, Rutilus frisii kutum

The pattern of haematology and blood biochemistry variations of healthy adult female kutum Rutilus frisii kutum (Cyprinidae) was investigated in the three reproductive states: maturing (autumn), pre-spawning (winter), and spawning (spring). Red blood cells, haemoglobin, and haematocrit were highest in autumn, whereas the highest values for white blood cells, mean corpuscular volume (MCV), and mean corpuscular haemoglobin (MCH) were observed in winter. With the exception of MCV and mean corpuscular haemoglobin concentration (MCHC), fish size had no effect on haematological and biochemical parameters. MCV was higher in larger fish, whereas the reverse trend was found for MCHC. Decreased levels of plasma glucose, cholesterol, and triglyceride in the pre-spawning period, when female ovaries were developing, may have been due to the combination of reproductive effects and food shortage in winter. Total protein levels were lower during the maturing period than during the pre-spawning period. The results of this study suggest that temporal variations in haematological and biochemical parameters of blood are significant and should be considered when these parameters are used to assess fish health status.