Anti-parasitic effects of Zataria multiflora extract to eliminate the Trichodina parasite and its effect on blood parameters of Persian sturgeon

           Today, use of medicinal plants is important for control of the disease-causing agents, including parasites, rather than chemicals. This study was conducted to evaluate the efficacy and effective dose of Zataria multiflora hydroalcoholic extract in the fight against external protozoan parasite (Trichodina). For this purpose, after determination of the lethal concentrations (LC50) of this extract on Persian sturgeon, a study was conducted to determine the effective dose (EC50). In this study, the effects of Zataria multiflora extract on white blood cells were also investigated. The results of differential white blood cells count in studies of EC50 extracts showed statistically significant differences in the level of lymphocyte, neutrophil and eosionophil in different treatments (P>0.05). The effective concentration of Zataria multiflora hydroalcoholic extract on Trichodina sp. was determined in the concentration range of 200 to 600 mg/l and this effective dose was calculated as 437.6 mg/l for one hour of bath time. This dose was classified in the category of substances with low toxicity and substitution Suitable chemicals. Therefore, this extract is recommended to remove Trichodina parasite in sturgeon fish farms.