Chicken immune cell assay to evaluate the immune-modulating effect of grape by-products

Agro-industrial by-products offer sustainable and cost-effective alternatives to traditional feedstuffs. Grape by-products (GP) come from winery and are known to be rich in phenolic compounds. We evaluated the immunomodulatory effect of GP on chicken immune cells by isolating peripheral blood mononuclear cells (PBMC) from chicken blood and exposing them to various GP forms. Original GP (oGP) was digested in vitro using the INFOGEST protocol to obtain digested GP (ivdGP). Phenolic compounds were extracted from oGP using a water:ethanol solution, yielding extracted GP (extGP). We measured total phenolic content in oGP and extGP with a colorimetric Folin assay. Chicken PBMC were treated for 24 h with oGP, ivdGP, and extGP, and immunophenotyping was applied using flow cytometry. The extGP treatment increased the proportion of dead cells but significantly enhanced CD4+CD25+ and CD8+CD25+ T cells activation, suggesting that extGP induced T cell activation without promoting proliferation. No significant changes were observed in CD4 and CD8 T cell activation with other treatments, nor did any treatment significantly affected B cells. To conclude, only extGP enhanced CD4 and CD8 T cell activation among the tested GP forms, highlighting its potential immunomodulatory role in chicken PBMC immune response. This suggests that specific GP forms can influence the immune system, providing insights for their use for poultry nutrition and health management.