booster effects of oregano (origanum syriacum) on newcastle disease vaccination in chickens

Background: newcastle disease (nd) is a major threat to poultry health and production worldwide. while vaccination is widely used, adverse vaccine reactions may impair poultry growth and health. natural feed additives, such as oregano (origanum syriacum), have shown immunostimulatory and protective properties.objectives: this study aimed to evaluate the immunostimulatory, protective, and growth-supporting effects of oregano supplementation in broiler chickens vaccinated against nd.methods: a total of 40 one-day-old broiler chicks were divided into four groups (n=10 each): negative control, positive control (nd vaccine only), and two experimental groups supplemented with oregano at 1 g/kg or 2 g/kg feed along with nd vaccination. immune response was assessed by enzyme-linked immunosorbent assay (elisa). body weight was recorded at days 1, 21, and 45. trachea, proventriculus, intestines, and cecum were collected for histopathological evaluation. data were analyzed using one-way anova followed by tukey post hoc test, with f values, degrees of freedom, and p values reported.results: the oregano-supplemented groups showed enhanced immune response, with the 1 g/kg group exhibiting significantly higher antibody titers (p≤0.05) than the vaccine-only group. body weight was highest in the 2 g/kg group (f3, 36=18.54; p<0.001). histopathological analysis revealed reduced lesion scores in oregano-treated groups, particularly at 2 g/kg. semi-quantitative scoring confirmed significant protective effects (p≤0.05)conclusion: oregano supplementation enhances humoral immunity, reduces nd vaccine-induced tissue damage, and improves growth performance. one g/kg dose primarily boosts antibody response, while 2 g/kg confers superior tissue protection and growth benefits.