Study on effect of shirazi thyme extract (Zataria multiflora) and Zingiber powdered (Zingiber officinale) on growth parameters non-specific immunity index and resistance of rainbow trout (Oncorhynchus mykiss) juvenile against of Yersinia ruckeri pathogen

In this study effects of Zataria multiflora powdered and Zingiber officinale extract on Oncorhynchus mykiss growth andimmunity system was investigated. 150 juvenile Oncorhynchus mykiss fishes with the average weight 31.40±1.43g (±SD) divide in to 3 treatments with triplicate. Each treatment feed with Zataria multiflora powdered and Zingiber officinale extract with 0 (control group) and 1percentage for 30 days. At the end of treatment blood samples were taken and immunological parameters were compared among the groups. To determine the effect of plant extracts in the bacterial challenge with pathogen, at the 30th day 15 fish from each treatment was injected by Yersinia ruckeri intraperitoneallyand mortality daily was recorded in two weeks.Theresults showed not any significant difference on growth factors (P>0.05). At the end of feeding period, most of the total protein, albumin, glucose, lysozyme, catalase, superoxide dismutase and hemolytic activity of complemant serum were observed in control group (p < 0.05). In the second phase of experimental and condition of post challenge with pathogen, most of the Glucose, lysozyme, catalase, superoxide dismutase and hemolytic activity of complemant serum were observed in treatment fed with 1% Zingiber powdered(p < 0.05). The highest time of survival rate of O. mykiss juvenile were observed in treatments fed with Zingiber powdered. Based on the results we can conclude that the use of 1% shirazi thyme andZingibermakes stimulates the immune system and increase resistance in rainbow trout.