Abstract: [Objective] To assess the effects of two traditional Chinese medicine immune enhancers on immunological response of broiler chicks to Newcastle disease vaccine. [Method] In total, 150 1-day-old male AA broiler chicks were randomly allocated into three groups, a control （CG） group, a Astragalus membranaceus （AM） group, and a Lycium barbarum （LB） group, with 50 individuals in each group. The CG group fed basal diet, while the AM and LB groups were supplemented with 1% AM powder and 1% LB powder in basal diet, respectively. At 14 and 35 days of age, the immune organ indexes were measured. The Newcastle disease virus antibody （NDV-Ab） titer was determined at 14,21, 28 and 35 days of age, and the contents of serum immunoglobulin were evaluated at 14 and 28 days of age. [Result] At 14 days of age, the spleen index （SpI） and bursa Fabricius index （BFI） in the AM group were 31.17% （P<0.01） and 34.86% （P<0.05） higher than those in the CG group, respectively, and the SpI in the AM group was 14.12% （P<0.05） higher than that in the LB group. At 35 days of age, the thymus index （ThI） and BFI in the LB group were 14.29% （P<0.05） and 9.76% （P<0.05） higher than those in the CG group, respectively; the ThI, SpI and BFI in the AM group were 18.37% （P<0.05）, 35.84% （P<0.05） and 15.85% （P<0.05） higher than those in the CG group, respectively; the SpI in the AM group was 19.92% （P<0.05） higher than that in the LB group. Compared with the CG group, the NDV-Ab titer of the LB group was increased by 34.78% （P<0.05） at 28 days of age, while that of the AM group was increased by 118.18% （P<0.05）, 75.00% （P<0.05） and 56.52% （P<0.05） at 14, 21 and 28 days of age, respectively. At 14 and 28 days of age, compared with the CG group, the content of serum immunoglobulin M （IgM） in the AM group was increased by 15.15% （P<0.05） and 11.76% （P<0.05）, respectively, and that of serum immunoglobulin G （IgG） was increased by 7.50% （P<0.05) and 14.15% （P<0.05）, respectively. In comparison to the CG group, the content of serum IgM in the LB group was 12.12% （P<0.05） higher at 14 days of age, and that of serum IgG was 11.32% （P<0.05） higher at 28 days of age. [Conclusion] Dietary supplementation of 1% AM powder or 1% LB powder improved the major immune organ indexes, NDV-Ab titer, and serum IgG and IgM contents of AA broiler chicks. The effects of 1% AM powder was superior.

Key words: broiler chicks, immune enhancer, immune organ index, Newcastle disease antibody titer, immunoglobulin