Determination of Some Hematological and Non-Specific Immune Defences, Oxidative Stress and Histopathological Status in Rainbow Trout ( Oncorhynchus mykiss ) Fed Rosehip ( Rosa canina ) to Yersinia ruckeri

The effect of the Yersinia ruckeri infection in the different tissues of 225 rainbow trout (Oncorhynchus mykiss) fed with rosehip (Rosa canina) was researched by evaluating a range of factors such as hematological and histopathological findings, non-specific immune parameters, liver antioxidant parameters, and then determined mortality and relative percentage survival (RPS) rates. The study comprises control groups (C+, C-) and rosehip experimental groups (REGs): R-10 (10%), R-20 (20%) and R-30 (30%). Following the 50-day feeding period, the fish were infected with Y. ruckeri and then blood, liver, spleen and kidney samples were taken. RBC, WBC, Hb, Hct and RBC indices, non-specific immune parameters, NBT, phagocytic activity and leukocyte formulas all significantly increased in R-20 compared to other groups. Antioxidant parameters SOD, CAT and GSH values increased in the R-20 and R-30 groups, and the lowest RPS value was detected in R-30 at 26.31%, while it increased in the R-20 group to 42.09%. R-30 showed no significant hematological and immunological effects, however, the immune cells were suppressed. In this research, R-20 was determined to be the ideal dose, taking into account both health indicators and hematological parameters, as a defense mechanism against Y. ruckeri, showing the best antibacterial and antioxidant effects.