Eimeria tenella: Ginsenosides-enhanced immune response to the immunization with recombinant 5401 antigen in chickens

Three-day-old specific-pathogen-free chickens were subcutaneously immunized with Eimeria tenella recombinant 5401 antigen (100 μg per chicken) with (0.25, 0.5 or 1.0 mg per dose) or without ginsenosides, and boosted with the same dosage 14 days later. The chickens were challenged with 6 × 104 homologous sporulated oocysts 14 day after the booster. The specific antibody response and lymphocyte proliferation in response to Con A were measured before and 7, 14, 21, 28, 35, 42 days after the immunization. Oocyst output, mortality, and lesion scores were measured to evaluate the protective effects of the immunization. The vaccine containing 0.5 or 1.0 mg ginsenosides per dose induces higher antibody response and lymphocyte proliferation in response to Con A than the vaccine without ginsenosides or containing 0.25 mg per dose. The oocyst output indicated that recombinant 5401 antigen with ginsenosides (0.5 and 1.0 mg per dose) gave a protection rate of 59.38 and 62.5%, respectively. The lesion score in the group vaccinated with recombinant 5401 antigen with 0.5 or 1.0 mg ginsenosides per dose were significantly lower than in group without ginsenosides or containing 0.25 mg per dose. Therefore, we conclude that ginsenosides have strong adjuvant effects at a dose of 0.5 or 1.0 mg when mixed with E. tenella recombinant 5401 antigen, and has a potential as an adjuvant in chicken vaccine.