Effect of Different Levels Tanacetum balsamita Hydroalcoholic Essential Oil on Broiler Chickens Performance and humoral and cell mediated immunity

Medicinal plant essential oil has antimicrobial and antioxidant properties and improve small intestine microbial population and feed digestibility and for this purpose its inclusion to broiler chickens’ diet as antibiotic replacement. Present study was conducted in order to compare the effect of different levels of Tanacetum balsamita hydroalcoholic essential oil with vitamin E and C on Ross-308 broiler chickens’ performance and immunity. Three hundred broiler chickens (equal number of male and female) were used in a completely randomized design in 6 treatments and 5 replicates with 10 birds in each. The dietary treatment consisted of: 1) basal diet as control group, 2 and 3) basal diet supplemented with 200 and 400 mg/kg Tanacetum balsamita hydroalcoholic essential oil, respectively, 4) basal diet supplemented with 200 mg/kg Vitamin E, 5) basal diet supplemented with 200 mg/kg vitamin C and 6) basal diet supplemented with 200 mg/kg virginiamycin antibiotic. The results showed that the amount of feed intake, body weight gain, feed conversion ratio and European production efficiency factor, IgG, IgM and total antibody titter against SRBC, New-castle disease and avian influenza virus’s antibody titer were not affected by dietary treatments (P>0.05). Treatments had no effect on toe web swelling index after 4 and 24h post injection period but broiler chickens fed diets containing 200 and 400 mg/kg Tanacetum balsamita essential oil had higher swelling index at 48h after injection whereas there were no significant differences between vitamin E and antibiotic groups (P<0.05) and chickens fed diets supplemented with 200 mg/kg essential oil and vitamin E and C had higher lymphocyte percentage and lower heterophil percentage and heterophil to lymphocyte ratio compared to control group (P<0.05). In conclusion, although Tanacetum balsamita essential oil improved cell mediated immunity of broiler chickens but the results revealed that due to its non-significant effect on broiler chicken’s performance and immunity, its addition to broiler chickens’ diet is not economically advisable.