A. A Abdulkadhim - Department of Veterinary Microbiology, College of Veterinary Medicine, Kufa University, Kufa, Iraq
F Mohammed Dughaim - Department of Veterinary Microbiology, College of Veterinary Medicine, Kufa University, Kufa, Iraq
A Ibrahim Ahmed - Faculty of Agriculture, Salahaddin University, Erbil, Kurdistan, Iraq

This trial was conducted to evaluate the effects of oregano essential oil supplementation at the concentration of ۵۰ mL/۱۰۰۰L of drinking water on immune response and growth performance in broiler chickens. A total of ۳۹۰ one-day-old Rose chickens were housed together in six experimental boxes (n=۶۵ each), including non-vaccinated groups and non-vaccinated oregano treated groups. Group A: vaccinated with LaSota vaccine via eye drop at ۵-, ۱۵-, and ۲۸-day-old adding oregano essential oil in drinking water ۱ day post-vaccination. Group B: vaccinated with LaSota vaccine via eye drop at ۵-, ۱۵-, ۲۸-day-old only without oregano essential oil. Group C: vaccinated with inactivated Newcastle disease (ND) vaccine at ۵-day-old via subcutaneous (SC) injection one dose adding oregano essential oil in drinking water ۱ day post-vaccination for ۳ days. Group D: vaccinated with inactivated ND vaccine at ۵-day-old via SC injection one dose only without oregano essential oil. Group E: non-vaccinated as the control group. Group F: non-vaccinated and adding oregano essential oil for ۳ days in drinking water as the control group. The effect of oregano essential oil in drinking water combined with two forms of live and killed ND virus vaccines on the immune responses and serum proteins was investigated in broiler chickens. The results showed the significant effect of oregano on the immune response of chicks in groups D and C that were vaccinated with the killed vaccine at ۲۳- and ۳۳-day-old. Based on the findings, a peak was recorded at ۳۸-day-old with a significant difference (P<۰.۰۵) in vaccinated and non-vaccinated groups, as well as a significant increase in ۳۸-day-old for group C (P<۰.۰۵), compared to other groups regarding the oregano effects on the immune response of groups. In addition, an increase in the serum protein was significantly different (P>۰.۰۵) in the vaccinated broiler chicks, and serum globulin showed a quantitative increase in the vaccinated broiler chicks, compared with non-vaccinated groups. However, the results showed that the effect of oregano was non-significantly different (P>۰.۰۵) and it had no beneficial effect on growth performance. The results of this study showed the effects of commercial Oregano supplementation (۵۰ mL/۱۰۰۰L drinking water), which increased serum total protein, including globulin, and provoked the best immunological response to ND vaccinations in broiler chickens. More research is needed to develop a state that may beneficially affect the health and uniformity of chickens.

Newcastle Disease vaccine, supplement oregano essential oil, Immune response, Serum Proteins, Chicken