In recent years, there has been growing interest in exploring natural alternatives to antibiotics in animal production. One such alternative is the use of essential oils derived from herbs and spices, which have shown promising results in enhancing the immune response and overall health of broiler chickens. The present study aimed to examine the comparative effects of ginger essential oils (GEO) and virginiamycin (VM) antibiotic on the weights of lymphoid organs and the antibody response in broiler chickens. A total of 300 one-day-old male broiler chicks were allocated randomly into 5 treatments, with 6 replicates per treatment. The dietary treatments consisted of a basal diet as the control, along with GEO-supplemented diets at inclusion levels of 100 (GEO1), 200 (GEO2), or 300 (GEO3) mg/kg, and a VM-supplemented diet with an inclusion level of 200 mg/kg. The results revealed that the administration of GEO2, GEO3, and VM diets resulted in a significant increase in the relative weight of the bursa and spleen (P < 0.05). The secondary antibody titer against infectious bursal disease and infectious bronchitis vaccines was significantly increased in the GEO2 and VM groups compared to the control group (P < 0.05). In conclusion, the findings of this study indicate that the inclusion of GEO at a concentration of 200 mg/kg in the diet resulted in improved immune responses, which were comparable to those of VM used as an antibiotic growth promoter.
