Immunoregulation of Lycium barbarum Polysaccharide in Vaccinated Chickens

The objective of the present study was to evaluate the effects of Lycium barbarum Polysaccharide (LBP) on immune responses in vaccinated chickens. A total of 600 Hy-Line Brown chickens aged 15 days old were randomly divided into four groups with three replicates per group and fifty chickens per replicate and all the chickens were injected with Newcastle Disease (ND) vaccine. Three experimental groups of chickens were injected with LBP 20, 10 and 5 mg kg(-1) (LBPH, LBPM and LBPL) and the control group were injected with equal dose normal saline (0.09% NaCl), respectively per day for 7 days. On the 7, 14, 21, 28, 35 and 42 days after vaccination, ten chickens were sampled randomly from each group and the serum was seperated for the determination of NDV-HI antibody titers by Micro Method. On day 10, 20, 30, 40 and 50 after vaccination, lion, blood samples from 5 chickens per group were collected to separate lymphocyte and determine the peripheral blood T lymphocyte proliferation with Methyl Thiazolyl Tetrazolium (MTT) Method. The content of CD4+ and CD8+ T cells were tested by using flow cytometry with Double Color Staining Method. The IL-2 levels were determined by ELISA Method and the whole body, bursa of fabricius and thymus were weighted for calculation of immune organ index. The results showed that LBP (10 and 20 mg kg(-1)) could significantly raised the ratio of CD4+ and CD8+T lymphocyte (p<0.01) and the production of IL-2. It also significantly enhanced the ND antibody titers, promoted the proliferation of peripheral blood T lymphocyte and increased immune organ indexes (p<0.01). These results indicated that LBP had significant immunoregulation functions of ND vaccine in chickens.