The Influence of Season Variation on Hematological Parameters and Oxidative Stress for Rainbow Trout (Oncorhynchus mykiss)

The parameters studied were RBC, Ht, Hb, erythrocyte index MCV, MCH, MCHC, and oxidative stress through SOD and GPx. For each parameter, blood samples were collected at specimens weighing between 100-140g in the summer season, 250-280 g in the fall, 270-300g in the winter and 320-350g in the spring. At the specimens studied the highest values of GPx and SOD were recorded in the spring season due to the stress caused by massive precipitation. During the study, the water temperature ranged between 5.1° C in winter and 19.2° C in summer and O2 ranged between 8.30 mg/l in the summer and 10.20 mg / l in winter. For most parameters, the highest values were recorded in the spring season and the lowest in the summer season. The data obtained in each season on Oncorhynchus mykiss species do not indicate pathological conditions but more an adaptive fish response to environmental conditions and can serve as a database for future research on welfare of salmonids.