Effect of water extract of marjoram (Origanum majorana L.) as an alternative to antibiotic growth promoter on immunity and serum lipid profile of broiler chicks

This experiment was conducted to investigate the effect of marjoram water extract as an alternative to antibiotic growth promoter on immunity and serum lipids profile of broiler chicks. One hundred and ninety two day-old broiler chicks were divided randomly into four treatment groups included: control, antibiotic (Flavophospholipol) and marjoram water extract at levels of 0.5 and 1% in drinking water. Antibody titer against Newcastle and Avian Influenza (H9 N2) viruses at 21 d (14 d post immunization), SRBC at 36 d (6 d post immunization), heterophil to lymphocyte ratio and albumin to globulin ratio at 42 d were measured. Serum concentration of triglyceride, cholesterol, LDL and HDL cholesterol were determined at 42 d. Results showed that higher antibody production against Newcastle and SRBC were attributed to 0.5% marjoram extract (P<;0.05). Antibody titer against Avian Influenza virus, heterophil to lymphocyte ratio and albumin to globulin ratio were not affected significantly by treatments. Experimental treatments had not effect on serum triglyceride, cholesterol and LDL-cholesterol but HDL-cholesterol were decreased in control group (P<;0.05). These results suggest that addition of marjoram extract at level of 0.5% seemed to have a positive effect on immune responses, and could be considered as a natural potential immunity enhancer for broiler chicks.