Analysis of the immunomodulatory effects of Honeysuckle leaf polysaccharides on cherry valley ducks based on transcriptomic techniques

This study aimed to optimize the extraction process of Honeysuckle leaf polysaccharides (HLP) and investigate their regulatory effects on immune function, as well as the underlying molecular mechanisms, in Cherry valley meat ducks. Using dried Honeysuckle leaves as the raw material, the water extraction-alcohol precipitation method was adopted to isolate HLP. Through single-factor experiments combined with response surface methodology (RSM), the optimal extraction parameters were identified as a solid-to-liquid ratio of 1:20, an extraction temperature of 90 °C, and an extraction time of 80 min, with a corresponding polysaccharide yield of 5.46 ± 0.18 %. A 21-day gavage administration model was established in 3-day-old Cherry valley ducklings. Combined in vivo and in vitro assays demonstrated that HLP exerted no cytotoxicity at concentrations ranging from 5 to 3000 μg/mL. HLP significantly increased immune organ indices in ducklings and markedly enhanced peripheral blood lymphocyte viability. Furthermore, co-administration of HLP with lipopolysaccharide (LPS) synergistically promoted lymphocyte proliferation. Transcriptomic profiling analysis revealed that HLP exerts immunomodulatory effects primarily by regulating the peroxisome proliferator-activated receptor (PPAR) signaling pathway and the cytokine-cytokine receptor interaction pathway. This study optimized the HLP extraction process and elucidated its multi-pathway synergistic immunomodulatory mechanism in poultry, thereby providing robust experimental and theoretical support for the development of HLP as a natural immunomodulator in sustainable livestock and poultry health management.