The effects of pseudostellaria heterophylla polysaccharide on humoral immunity and gene expression of splenic lymphocytes in chicks

This study aimed to evaluate the effects of dietary Pseudostellaria heterophylla Polysaccharide (PHP) on humoral immunity and spleen lymphocyte gene expression in chicks. A total of 270 one-day-old healthy Gushi chicks were randomly allocated into three groups: Group A was fed the basic diet without vaccination; Group B received the basic diet and underwent immunization; Group C was provided with the basic diet supplemented with 200 mg/kg PHP, coupled with immunization. Samples were collected at 7, 14, 21, 28, 35, 42, and 49 days. Compared to Group A, Group B showed significantly higher specific antibody titers following the second immunization, along with increased spleen and bursa indices at day 35, and elevated serum levels of IgG, C3, and IL-4. Compared with Group B, Group C demonstrated higher specific antibody titers after the first immunization, enhanced immune organ indices at day 35, and increased serum concentrations of IgG, C3, IL-4, IL-6, and IFN-γ when compared to Group B. Additionally, gene expression analyses revealed upregulation of key immune-related genes (IFN-γ, CD40, CD80, CD86) in the spleen and (IL-4, IFN-γ, CD40, CD86) in the bursa (P < 0.05). Transcriptome analysis of spleen lymphocytes at 35 days identified 627 differentially expressed genes between Groups B and C, enriched in pathways related to Th17 differentiation and Toll-like receptor signaling, with EGR-1 and CD40LG identified as critical genes. These findings suggest that PHP enhances humoral immunity by promoting antibody production, increasing immune organ indices, elevating serum factors, and modulating related gene expression.