Objective Various environmental stressors impair poultry productivity by increasing oxidative stress. This study evaluated the performance and health status of broilers supplemented with either the medicinal plant Dracocephalum moldavica L. powder (DP) or a commercial probiotic (Lactofeed) under oxidative stress induced by dexamethasone. Methods A total of 300 one-day-old chicks were enrolled in a completely randomized design with a factorial arrangement of six treatments, each consisting of five replicates of 10 chicks. The experimental treatments were: 1) basal diet without feed additives and no challenge, 2) basal diet with 0.01% Lactofeed, 3) basal diet with 0.4% DP, 4) basal diet and challenged with dexamethasone (2 mg/kg body weight), 5) basal diet with 0.01% Lactofeed and challenged with dexamethasone, and 6) basal diet with 0.4% DP and challenged with dexamethasone. Growth performance, carcass traits, and internal organ weights were evaluated. Gastrointestinal pH and ileum histology were assessed on days 28 and 42, while cecal microbial counts were determined on days 14, 28, and 42. Antibody titers against Newcastle disease and avian influenza viruses, as well as white blood cell counts were measured in serum samples collected on days 14, 28, and 42. Results Dexamethasone challenge negatively impacted performance, select carcass traits, white blood cell count, and ileum villus height (p=0.039), while reducing cecal E. coli and coliform counts (p=0.001). It suppressed humoral immune response to Newcastle disease virus on day 28 but enhanced it at day 42. Lactofeed and DP additives significantly improved feed intake, body weight gain, white blood cell count, intestinal histology, and microbiota, largely independent of dexamethasone challenge. Conclusion While dexamethasone challenge induced various physiological stresses in broilers, both Lactofeed and DP feed additives demonstrated potential in mitigating these effects, improving overall performance and gut health parameters regardless of stress conditions.
