Effect Of Astragalus Root Extraction On Chicken Growth And Immunological Function

Forty healthy one-day-old chickens were normally vaccinated with NDV vaccine and divided into 5 groups, including 1 controlled group and 4 test groups, 8 for each. Every test group was supplemented different 4 kinds of Astragalus root extraction in water from seven-day-old for 6 weeks. Every week, HI test results with heart blood and body weight were recorded to calculate the NDV antibody titers and the percent of the body weight gain. After forty-two days, the chickens were killed and the index numbers of thymus, spleen and bursa Fabricius were calculated. The morphological structure of mucosal epithelium in the small and large intestines, cecal tonsil and gut-associated lymphoid tissues (GALT) were observed. Agarose diffusion assay was used to reveal their antibacterial activity to 6 bacteria strains. The results demonstrated that the 4 kinds of Astragalus root extraction have no antibacterial activity and could significantly enhance the percent of the body weight gain, the NDV antibody titers, the index numbers of thymus, spleen and bursa Fabricius ,the numbers of gut mucosa immunological cells and the thickness of gut mucosa, height of villus and V/C value in chickens of 4 test groups (p<0.05 or p<0.01) .