Effects Of Vaccination Stress On Immune-Related Factors In Piglets

In modern breeding industry, the vaccine plays a vital role in prevention and control of livestock diseases. However, as a special kind of stress factor, vaccination also might harm animal health. It might not only slow animal growth and affect their performance, but also cause the deaths, and therefore brings a serious economic loss. Stress can affect the immune function by regulating the neuro-endocrine-immune network. The purpose of this study is to test the effect of vaccination stress of classical swine fever (CSF) and foot-and-mouth disease (FMD) vaccines on the immune function of piglets.In this study, twenty-seven60-day-old ternary hybrid piglets of Duroc, Landrace and Yorkshire were used. These piglets were randomly divided into three groups, including CSF vaccine, FMD vaccine and saline groups. Blood samples were taken from piglets at12h before vaccination, and2h,4h,8h,24h,48h,5d,7d, and10d after vaccination. Three piglets of each group were sacrificed at3d and5d and livers and lymphoglandulae mesentericae were taken for detection.In order to investigate the effect of vaccination stress on cytokine and specific antibosies, ELISA was used to detect the levels of IL-2, IL-4, IL-6, IL-10, IFN-γ, and CSF and FMD antibodies in the sera of the experimental piglets. The results indicated that CSF vaccine effectively caused the production of specific antibody after vaccination; in CSF group, IFN-y level in serum significantly increased at48h and10d (P<0.05), the level of IL-4decreased at24h,48h,5d and7d (P<0.05), IL-6significantly declined at5d (P<0.05), and the expression level of IL-10significantly declined at2h,4h and8h (P<0.05). In FMD group, the level of IFN-y significantly increased at2h,4h,8h,7d and10d (P<0.05), and the level of IL-6significantly declined at24h,48h,5d and7d (P<0.05).To examine the the immune-related factors of vaccination stress in tissues, RT-PCR was used to determine the mRNA expression level of HSP90, C-reactive protein (CRP), haptoglobin(Hp), pig major acute phase protein(Pig-MAP), Toll-like recptors2(TLR2) and TLR4. The results showed that at3d and5d after vaccination, the vaccination stress caused HSP90level in liver decrease (P<0.01) while CRP rapidly rose (P<0.01); the HP decreased (P<0.01) and the Pig-MAP rose (P<0.01). It is also found that after vaccination, the TLR2level in lymphoglandulae mesentericae increased at3d and5d (P<0.01), and TLR4level decreased at3d (P<0.05) while increased at5d (P<0.01).These results indicated that vaccination stress can affect the immune function of piglets and the interaction of cytokine will influence animal health.