Effect Of Astragalus Composing Prescriptions On The Immunological Functions In Broilers

Three experiments were conducted to study the effect of the Astragalus and its composing prescriptions on immunological functions in broilers.In experiment 1, the broilers with high concentration of maternal antibody were treated with the water that was supplemented with Astragalus and its composing prescriptions. The broilers were vaccinated by routine method of dropping to the eyes with ND-IV. In order to find an optimal composing prescriptions, the HI level in the serum was determined at the age of 9,20,28,35,40,45; the body weight and the feed consumption was calculated at the age of 46. The results showed that the Astragalus and its composing prescriptions could improve and prolong the serum HI level. The effects of the composing prescription 3 were especially significant.In experiment 2 and 3, the dose effect of the optimal composing prescription on the broilers'humoral and cellular immunity was studied. The indexes of the bursa of Fabricius, spleen and thymus were determined to investigate the mechanism of the immunity improvement.The result showed that when treated with the composing prescription 3, the serum HI level was improved by 1.2 with a good equality and the effective HI lasted 14-18 days longer than the controls'. The body weight, survival percent and the ratio of feed to body weight were improved by 9.5%, 3.4%, and 9.0%, respectively. The indexes of the bursa of Fabricuis and spleen treated with composing prescription 3 were significantly higher than the controls at the age of 9 and 45 (P<0.01). There was no significant difference in the thymus index between composing prescription 3 and controls at the age of 9 (P>0.05), but the significant difference was found at the age of 45 (P<0.01). The blood lymphocyte EAC anadem ratio and T lymphocyte ANAE masculine ratio were significant higher than the controls'(P<0.01) but no significant difference was observed between vaccinated and unvaccinated groups (P>0.05). When the broilers were treated with composing prescription 3, their blood red cell C3b anadem ratio was significant higher and the IC anadem ratio was significant lower than the controls'(P<0.01), but no significant difference was observed between vaccinated and unvaccinated groups (P>0.05) at the age of 9 and 45.In conclusion, the Astragalus and its composing prescriptions can improve the broiler's immunity functions by the way of accelerating the development of the immune organs, and promoting the activity of humoral and cellular immunity.