Onion and Garlic Mixture Enhances Performance and Survival in Broiler Chickens Infected with Newcastle Disease Virus and Infectious Bronchitis Virus

Abstract Vaccines have become less effective due to more virulent antigens, prompting increased recommendations for natural herbs and phytochemicals. This study aimed to evaluate the effects of an onion and garlic mixture (OGM) on performance, carcass composition, liver enzymes, intestinal morphology, and mortality in broiler chickens infected with Newcastle Disease Virus (NDV) and Infectious Bronchitis Virus (IBV). 300 chicks were divided into five treatment groups: the control group (T1) received a basal diet, while groups T2, T3, T4, and T5 were supplemented with 1.5%, 3%, 4.5%, and 6% OGM, respectively. All chicks were infected with NDV on day 7 and IBV on day 25. Results indicated that 3% OGM significantly improved average weight gain (AWG) and feed intake (AFI) during the starter phase (P ≤ 0.05) without affecting performance in the grower phase. OGM supplementation increased AWG, reduced mortality in NDV-infected chicks, and lowered mortality in IBV-infected chickens during the finisher phase. Although there were no significant changes in internal organ weights, intestinal morphology, or NDV antibody levels, OGM reduced liver damage and enhanced immunity against IBV by boosting antibody production (P ≤ 0.05). In conclusion, including OGM in chicken diets boosts their immune systems, supports growth, and lowers mortality rates. Therefore, adding OGM at 1.5% or 3% in broiler diets can enhance performance and reduce mortality, minimizing economic losses in the poultry sector.