Effects of Mentha Pulegium L and Zataria multiflora on Hematological Parameters, Oxidative Stress Biomarkers and Antibody Titter Resulted from Newcastle and Gumboro Vaccines in Broiler Chickens

Recently, herbal supplements have replaced the synthetic ones, due to several advantages. This study was conducted to investigate the effects of dried powders of aerial parts of Mentha pulegium L and Zataria multiflora on hematological parameters, oxidative stress biomarkers and antibody titter resulted from Newcastle and Gumboro vaccines. One hundred and twenty 1-day ROSS (308) chickens with 4 treatments and 3 replicates containing 20 birds in each were kept for 42 days.  The treatments were: 1) Control (basal diet); 2) Pennyroyal (200 mg/kg Pennyroyal + basal diet); 3) Thyme (200 mg/kg thyme + basal diet), 4) the combination (200 mg/kg+200 mg/kg of both herbal supplements + basal diet). The following hematological parameters were measured in the serum samples using standard assay kits: total protein, albumin, globulin, glucose, urea, triglyceride, cholesterol, high, low and very low density lipoprotein. The activities of 3 key antioxidant enzymes including superoxide dismutase, glutathione peroxidase and catalase as well as malondialdehyde content and total antioxidant capacity were measured as biomarkers of oxidative stress. Vaccination was done based on the regional standards and primary and secondary antibody titters were measured against Newcastle and Gumboro using HI and ELISA methods, respectively, 10 days after the last vaccination. The obtained results showed that the essential oils of the plants contain numerous active biocompounds and herbal supplements could alter biochemical parameters and oxidative stress biomarkers. Generally, the activities of superoxide dismutase was increased but catalase was decreased. Moreover, the activity of glutathione peroxidase remained constant. In addition, malondialdehyde content was declined but total antioxidant capacity was elevated. Furthermore, the secondary titers of the antibodies were significantly increased. The results of this study showed that supplementation with pennyroyal and dill dried powders can improve hematological parameters, enhance the antioxidant potency and immune system of broiler chickens. However, apparently the combination of the both plants has synergistic effects.