en aquaculture aquaculture پژوهشي Orginal research papers <p>A 6 week study was conducted to assess the effects of wood betony (WB), <em>Stachys lavandulifolia </em>extract on growth performance, hematological and biochemical parameters of common carp, <em>Cyprinus carpio</em>. Different levels of the WB extract (0, 2, 4 and 8 % weight per weight, W/W, 0WB, 2WB, 4WB and 8WB) in the diet were used. The results showed that final weight and weight gain were significantly improved by WB (<em>p</em><0.05), while other growth parameters such as food conversion efficiency and condition factor did not change (<em>p</em>>0.05). There were no significant differences in hemoglobin, hematocrit, mean erythrocytes of hemoglobin, mean erythrocyte volume, mean hemoglobin erythrocyte concentration and white blood cell (WBC) counts (<em>p</em>>0.05), while, red blood cells (RBC) counts showed significant declining trend by increasing the level of the plant extract from control to 8WB (<em>p</em><0.05). Significant elevation in the levels of total protein, albumin and globulin and albumin/globulin ratio by increasing WB concentration in the diet were observed (<em>p</em><0.05). Diet enriched by WB could decrease serum level of triglycerides and cholesterol in comparison with the control (<em>p</em><0.05). Based on the results of this study, it could be concluded that feeding common carp with WB can improve growth and some immunity characteristics as well as lipid metabolism..</p> Medicinal herb, Immunity, Lipid metabolism, Common carp, Cyprinus carpio. 805 817 http://jifro.ir/browse.php?a_code=A-10-167-3&slc_lang=en&sid=1 S Bahrami Babaheydari 100319475328460014745 100319475328460014745 No F Paykan Heyrati 100319475328460014746 100319475328460014746 No S Dorafshan sdorafshan@cc.iut.ac.ir 100319475328460014747 100319475328460014747 Yes N Mahboobi Soofiani 100319475328460014748 100319475328460014748 No M.R Vahabi 100319475328460014749 100319475328460014749 No