| In order to provide a basis theoretical on developmenting the active ingredients of Ginkgo biloba into green animal feed additives and animal immunoenhancer, The effects of Extracts Ginkgo biloba (EGB) on the immune function of broiler were studied in vivo and in vitro Experiments. Experimental was designed by single-factor, 360 one-day-old AA female broiler were divided into 5 treatments randomly , each treatment had 6 duplications, and 12 broiler in each duplication. All broiler were fed for 42 days. The first group was control group, which was fed with basal diet only; The second group was fed with the basal diet of adding aureomycin at 90 mg/kg; The other 3 groups are test group, which were fed with basal diet containing 0.15%, 0.2%, 0.25% EGB respectively. According to NRC (1994), the whert-corn basal diet which met the nutrition reqirement of broiler was prepared. All of group were inoculated with Newcastle disease - infectious bronchitis bivalent vaccine at 7 and 21-day-old. 12 broiler were selected randomly (2 broiler per duplication)from each group to test its productive performance, the relative weight of immune organs, humoral immunity, the levels of cell factor, the transformation rate of peripheral blood, spleen lymphocyte at 21,28 and 42 days; The effects of different concentration and EGB-containing serum on the proliferation of splenic T lymphocyte and the secretion of IL-1, IL-2 and TNF-αof lymphocyte were alse studied in vitro test. The results were as follows:(1) The diet adding different level EGB could improve the growth performance of broiler. Diet with 0.2% EGB can significantly improve the survival rate of broiler, daily gain and lower the feed Conversion ration, compared with the control group, the group which adding 0.2 %EGB improved the survival rate by 4.4% (P<0.05), average daily gain increased by12.9% (P<0.05), the feed Conversion ration reduced by 11.4% (P<0.05) at the end of experiment.(2) The diet adding different level EGB could increase the weight of immune organ. Compared with the control group,the group which adding 0.2%EGB increased the most at 28- day-old, spleen index, thymus index, Bursal index increased by 29.9% (P<0.05), 13.4% (P<0.05 ),15.4% (P<0.05).(3) The diet adding different level EGB could improve the humoral immune function of broiler. EGB could improve the level of IgG, IgM, IgA, complement C3, complement C4 of serum.The IgG, IgM, IgA of the testing group which adding 0.2% EGB increased the most at 42 day-old. IgG ,IgM, IgA,increased by 95.5% (P<0.05), 90.8% (P <0.05) and 24.5% (P<0.05) respectively than that of the control group. The Complement C3, C4 of the group adding 0.2% EGB increased the most at 21- day-old. Compared with the control group, C3, C4 increased by 95.4% (P <0.05) and 98.8% (P<0.05) respectively .(4) The diet adding different level EGB could improve the levels of cytokine in broiler. EGB could improve IL-1, IL-2, IFN, TNF-α. For IL-1, IL-2, IFN of serum. the group adding 0.2% EGB increased most at 42 -day-old. IL-1, IL-2 increased by 55.8% (P<0.05) and 13.2% (P>0.05) respectively than that of control group. IFN increased by 17.1% (P <0.05) than that of control group. TNF-αincreased the most in the group adding 0.2% EGB at 21 day-old.which increased by 44.3% (P<0.05) than that of control group.(5) The diet adding different level EGB could improve lymphocyte transformation rate of peripheral blood and spleen of broiler. The group adding EGB could significantly enhance lymphocyte transformation rate, especially the group adding 0.2% EGB increased most at 42-day-old.The lymphocyte transformation rate of peripheral blood and spleen increased by 18.3% (P<0.05) and 25.6% (P<0.05) respectively than that of control group.(6) Adding different concentrations of EGB directly in vitro could enhance lymphocyte proliferation and secretion of IL-1, IL-2, TNF-α.The group adding 70g/L EGB showed the best after culture for 48h. IL-1, IL-2 ,TNF-αincreased by 30.0% (P <0.05), 109.8% (P<0.05), and 69.7% (P<0.05) respectively than that of control group.(7) The serum containing EGB could enhance the proliferation of the broiler spleen lymphocyte and secretion of IL-1, IL-2, TNF-α. The serum of broiler adding 0.2% EGB in the diet, which were fed for 42-day-old, showed the best after culture for 48h, the proliferation of broiler spleen lymphocytes increased by 12.9% (P<0.05) than that of control group, IL-1, IL-2, TNF-αincreased by 18.1% ( P<0.05), 33.0% (p <0.05) and 38.4% (P<0.05) respectively than that of control groupp.The study shows that the Ginkgo biloba extract could improve growth performances and immune function of broiler. |
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