Effects of Proanthocyanidin-rich Extract from Pinus radiata Bark on Immune Responses of Broiler Chickens

Abstract

Proantocyanidins are naturally occurring compounds that are widely found in fruits, vegetables, nuts, seeds, flowers and bark. In part I, we evaluated the immunomodulatory effects of proanthocyanidin-rich extract (PAE) from Pinus radiata bark in specific pathogen free (SPF) White Leghorn chickens. Proliferation of peripheral blood mononuclear cells was significantly enhanced in chickens treated for 2 weeks with 20 ㎎/㎏ PAE. Proliferation of splenocytes and bursal cells was significantly enhanced in chickens treated for 5 weeks with 5, 10, and 20 ㎎/㎏ PAE. Thymocyte proliferation was significantly enhanced in chickens treated for 5 weeks with 5 and 10 ㎎/㎏ PAE. These effects were markedly enhanced by the presence of lipopolysaccharide, which actedon B cells responsible for humoral immunity, and concanvalin A, which acteddirectly on T cells involved in cell mediated immunity. PAE significantly promoted the expression of Th1 cytokine (interferon-gamma) and decreased the expression of Th2 cytokine (interleukin-6). In part Ⅱ, we evaluated the immunomodulatory effects of proanthocyanidin-rich extract (PAE) from Pinus radiata bark in broiler. Proliferation of peripheral blood mononuclear cells and thymocytes was significantly enhanced in 2.5, 5, 10 ㎎/㎏ PAE-treated broiler chickens. Proliferation of splenocytes was significantly enhanced in 1.25, 2.5, 5, 10 ㎎/㎏ PAE-treated broiler chickens. These effects were markedly enhanced by the presence of LPS, which acts on B cells responsible for humoral immunity, and Con A, which acts directly on T cells involved in cell mediated immunity. PAE significantly promoted the expression of interleukin-18 and interleukin-1 β. In part Ⅲ, We evaluated the immunomodulatory effects of proanthocyanidin-rich extract (PAE) from Pinus radiata bark in Korean native chickens. In experiment 1, proliferation of peripheral blood mononuclear cells (PBMCs) was significantly enhanced in chickens administered for 2 weeks with 1.25, 2.5, 5 and 10 ㎎/㎏ PAE. Proliferation of splenocytes and thymocytes cells was significantly enhanced in chickens administered for 5 weeks with 1.25, 2.5, 5 and 10 ㎎/㎏ PAE. In experiment 2, proliferation of PBMCs, splenocytes and thymocytes in the PAE-administered chickens for 6 weeks were continuously higher than other groups and significantly promoted the expression of Th1 cytokines (IL-2, IL-12, and IFN- γ). Also, the CD4+CD8? (Th1 cell) and Bu-1+ (B cell) cell population significantly upregulated after 4 weeks in PAE-administered chickens.