Performance, immunity, and serum biochemical parameters in broiler chickens fed diet supplemented with Zataria multiflora essential oil

 Zataria multiflora Boiss (ZM) is a thyme-like plant reported to have immunomodulatory properties. This study was aimed to examine effects of ZM essential oil on performance, biochemical and immunological parameters in broilers. Two hundred and forty, broiler chickens were divided into 4 groups. CON considered as control group received basal diet, T100, T200 and T400 treated by basal diet supplemented with ZM 100, 200 and 400 mg/kg feed, respectively. Body weight and feed intake were recorded at 14, 28, and 42 days of age. At the end of experiment, eight broilers per group were slaughtered and carcass portion yield was calculated. Humoral immune response efficacy by injection of 5% sheep red blood cell into the pectoral muscle of birds was evaluated. This study showed that supplementation of ZM promoted the weight gain in T200 as compared to other groups (P<0.05). Also, the best food conversion ratio was achieved in the same group. On the other hand, ZM supplementation in all of the doses used, did not cause significant increase in carcass portion yield (P<0.05), except for liver weight, which was significantly increased in T400. Serum biochemical analysis showed that levels of total protein, albumin and globulin were highest in T200 while the lowest were in T400; addition of ZM especially at the dose of 200 mg/kg improved immune responses in broilers (P<0.05). According to the results of present study, supplementing broilers diet with ZM could have favorable impact on performance and immunity.