Evaluation of oxygen changes on survival, some stress indices and hematological and immunological factors in Caspian Sea salmon (Salmo trutta caspius)

Caspian brown trout (Salmo trutta caspius) is one of the most valuable fishes in the Caspian Sea and has great value due to its marketability, appearance and taste of meat. This study was carried out to determine the effects of oxygen changes on survival, some stress indices and hematological and immunological factors in Caspian Sea salmon (Salmo trutta caspius). 210 fish (50 10g) were randomly selected and placed in tanks with aerator and oxygen capsule. Fish were divided in 3 treatments with 3 replications including treatment hypoxia (2-3 mg/L oxygen), treatment control or normoxia (7-8 mg/L oxygen) and treatment hyperoxia (12-14 mg/L oxygen). Blood sampling were performed for 12 and 24 hours. The results showed that fish had no mortality in the different oxygen treatments. The effect of oxygen showed that there were significant differences in WBC, RBC, hemoglobin, hematocrit, neutrophil, lymphocyte, cortisol, glucose, lactate, lysozyme, total immunoglobulin, IgM, albumin, and total protein (P<0.05). In general, 7-8 mg/L oxygen is the most favorable condition for Caspian brown trout. Because the most appropriate values of factors were observed more in this group, which showed a significant difference with other treatments.