Effects of pidotimod soluble powder and immune enhancement of Newcastle disease vaccine in chickens

•Pidotimod used as a new immunologic adjuvant is proposed.•The optimal dosage is obtained.•Pidotimod improve the immune efficacy of Newcastle disease vaccine.•Pidotimod relies on enhance cellular immunity and humoral immunity.

The aims of this study were to prepare pidotimod (PDM) soluble powder and to investigate the immune enhancement properties of PDM in chickens vaccinated with Newcastle disease virus vaccine. In vivo experiment, 360 6-day-old chickens were averagely divided into 6 groups. The chickens, except blank control (BC) group, were vaccinated with Newcastle disease vaccine (NDV). At the same time of the vaccination, the chickens in three PDM groups were given water with PDM for 5 days, respectively, with the PDM at low, medium and high concentrations (0.25 g/L, 0.5 g/L, 1 g/L), in control drug group was treated with 0.2 ml/PDM dose via drinking water, in vaccination control (VC) and BC group, with equal volume physiological saline, once a day for five successive days. On days 14, 21 and 28 after the vaccination, the growth performance, the lymphocyte proliferation, serum antibody titer, the CD4/CD8 cell ratios and interleukin-2 (IL-2) and interferon-gamma (IFN-γ) were measured. The results showed that PDM at suitable dose could significantly promote growth performance, lymphocyte proliferation, enhance serum antibody titer, CD4/CD8 cell ratios and improve serum IL-2 and IFN-γ concentrations. It indicated that PDM could significantly improve the immune efficacy of Newcastle disease vaccine using doses of 0.5 g/L, these results are consistent with the drug acting as an immunopotentiator.