Comparison of the effect of two phytogenic compounds on growth performance and immune response of broilers

A comparative evaluation of the two commercial essential oils of oregano in broiler diets on growth performance and immune responses was the purpose of this experiment. A total of 200-d-old Ross 308 chicks were used in a completely randomized design with 4 treatments and 5 replicates, with 10 birds in each. Dietary treatments included: (1) control (without phytogenic), (2) commercial blend of phytogenics (CBP; 150 ppm), (3) oregano essential oil (OEO; 300 ppm), and (4) OEO (500 ppm). During the entire period, ADFI was lower (P < .05) in CBP-fed birds than control, but was not different among CBP and either level of OEO (P > .05). European production efficiency factor was greater (P < .05) for broilers fed 300 ppm OEO than those fed control diet or CBP. Broilers fed 300 ppm OEO produced higher secondary total antibody titre against sheep red blood cell (P < .01) and their Immunoglobulin G titre was higher (P < .05) than those fed control or CBP. Serum heterophil counts (P < .01) and heterophils to lymphocytes ratio (P < .05) were lower in birds fed 300 ppm OEO or CBP than the control. Supplementation of OEO at the rate of 300 ppm in diet led to beneficial effects on performance and immune response of broilers.