Mechanism And Effect On Immune Function And Interleukin 2 Activity Of Chicks By Probiotics And Probiotics With ND Vaccine

The experiment was conducted by using of one-day-old chicks, the perpheral blood, thymus, bursa of Fabricius and spleen were sterilely removed for the culture of their lymphocytes. The T lymphocyte proliferative responses were determined, and supernatants from concanavalin A (ConA) stimulated cultures were assayed for the inductive activity of interleukine-2 (1L-2) . The B cells were stimulated with phorble myristate acetate (PMA) to determine the B lymphocyte proliferative responses. The inductive activity of IL-2 and lymphocyte proliferation of probiotics-fed chicks , ND-vaccinated and probiotics-fed chicks and following challenged with NDV were examined by using MTT method. The results were as follows:Chicks were fed with probiotics at one day age and changes of cytokine production and immunological functions were studied. The T lymphocyte IL-2 inductive activity of thymus and spleen was significantly higher from 4 to 10 days post feed(PF) than in control unfed group chicks (P0.05,P<0.01) . The peripheral blood , thymus and spleen T lymphocyte proliferation were significantly enhanced in probiotics-fed chicks from 4 to 10 days PF (P<0.05,P<0.01) . B lymphocyte proliferation in peripheral blood and immune organs of probiotics-fed chicks were greatly raised from 7 to 18 days and from 4 to 10 days PF respectively (P<0.05,P<0.01) . These indicate that molecular immunoregulatory function of immune organs was markedly enhanced in probiotics-fed chicks, and the cellular and humoral immune function were significantly strengthened in both the primary and secondary immune organs and peripheral blood of probiotics-fed chicks. The cellular and humoral immune functions were significantly strengthened in immune organs was closely correlated with the enhancement of molecular immunoregulatoru function in probiotics-fed chicks. This result was reflected in the expression of lymphocyte proliferation in peripheral blood.Chicks were fed with probiotics. Five days later, the probiotic-fed chicks were vaccinated with ND, unfed chicks as control group. Levels of cytokine production and T, B lymphocyte proliferation were determined throughout the experiment. Thymic and splenic T lymphocyte IL-2 inductive activity was significantly higher in probiotics-fed and ND-vaccinated chicks than singly ND-vaccinated chicks from 7 to 21 days post vaccination (PV) (P<0.05,P<0.01). The peripheral blood, thymus and spleen T lymphocyte proliferation were significantlyenhanced in probiotics-fed and ND-vaccinated chicks from 7 to 14 days and 7 to 21 days (PV) respectively (P<0.05,P<0.01) . B lymphocyte proliferation in Peripheral blood, bursa and spleen of probiotics-fed and ND-vaccinated chicks were greatly higher from 7 to 21 days than singly ND-vaccinated chicks ( P<0.05,P<0.01 ) . These indicate that molecular immunoregulatory function and the cellular and humoral immune responses were significantly strengthened in both the primary and secondary immune organs of probiotics-fed and ND-vaccinated chicks . The cellular and humoral immune responses were enhanced was closely correlated with the enhancement of molecular immunoregulatoru function. The effect of ND vaccinate used with probiotics was better than that singly ND-vaccinated used. It indicated that probiotics play a significant role as immunopotentiator.All of the probiotics-fed and ND-vaccinated chicks were successfully protected post challenged with NDV. At the meantime, inductive activity of IL-2, T and B lymphocyte proliferation were still higher than that of singly ND-vaccinated chicks, while those in unvaccinated control group chicks were markedly dropped (P<0.05,P<0.01) . These implied that the protective efficacy of probiotics with ND vaccine is closely correlated with the level of molecular immunoregulatory function and the situations of cellujar immune and humoral immune functions of probiotics-fed and ND-vaccinated chicks.The inductive activity of IL-2 and lymphocyte proliferation in probiotics I group chicks were higher than that of probiotics II group chicks thr...