Effects of methanol extract of Satureja hortensis on growth, serum hematological and biochemical factors on rainbow trout (Oncorhynchus mykiss)

In this study, to find an alternative for chemical growth an immune stimulant, the effects of methanolic extract of Savory leaf on the diet of rainbow trout on growth, blood parameters, biochemical and immune responses was investigated. After adaptation period, 360 fishes (with average weight of 14±1.7 grams) were fed with trial diets supplemented with 0% (as control), 1%, 2% and 3% of savory extract for 60 days and then were investigated. Results showed that the final weight in treatment 2 was higher than the control group and the FCR in all the treatments was lower than the control (p < 0.05). As well as the number of red and white blood cells, hemoglobin and hematocrit in the control group were significantly lower than the other groups (p < 0.05). The lowest level of glucose and the highest level of triglycerides, creatinine and cholesterol were observed in the control group (p < 0.05). Aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) enzyme levels were significantly higher in the 3% group than in the control group but the alkaline phosphatase (ALP) was lower than the control group (p < 0.05). Total protein in treatments 2 and 3, and the level of lysozyme activity in all treatments were significantly higher than the control group (p < 0.05). According to the results, the beneficial effects of savory in different amounts, especially 2% on growth performance, immune response and hematological parameters fish rainbow trout were observed.