Effect of dietary supplements of Artemisia dracunculus extract on the haemato‐immunological and biochemical response, and growth performance of the rainbow trout (Oncorhynchus mykiss).

The current research was conducted to examine the effect of Artemisia dracunculus (AD) extract on growth performance, haemato‐immunological, biochemical parameters, and mucosal immunity in the rainbow trout (Oncorhynchus mykiss). The fish were fed with a diet supplemented with 0 (control), 1%, 2% and 3% AD for 8 weeks. The findings indicated that in all groups fed AD, especially at the 2% level, the growth parameters and survival rate significantly increased compared with the control group. Blood biochemical parameters, creatinine, glucose, lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and triglyceride were decreased significantly in AD‐treated groups. Total serum protein (TSP) levels, lysozyme (LYZ) and respiratory burst activities (RBA) were increased in the fish fed with AD. TSP levels, ALP and protease (PA) activities in the mucus were significantly increased following fish fed with AD. Increased in the total immunoglobulins (Ig) and superoxide dismutase (SOD) activity were observed in the fish fed with 3% AD. Fish fed with 2% AD showed the highest levels of alternative complement (ACH50) significantly. In addition, the mucus bactericidal activity was significantly increased in some treatments fed AD diet against Lactococcus garvieae and Aeromonas hydrophila. After infection with Yersinia ruckeri, there was a reduction in the mortality rate in the AD‐fed groups compared with the control group. Thus, it can be concluded that diets supplemented with AD can significantly impact diverse physiological parameters in fish, improving their growth performance, blood biochemical parameters and immune response. [ABSTRACT FROM AUTHOR]