Immunomodulatory effect of a proanthocyanidin-rich extract from Pinus radiata bark by dosing period in chickens

We evaluated the immunomodulatory effects of a proanthocyanidin-rich extract (PAE) from Pinus radiata bark in Korean native chickens. In experiment 1, proliferation of peripheral blood mononuclear cells was significantly enhanced in chickens administered 1.25, 2.5, 5, and 10 mg/kg of PAE for 2 wk once daily by oral gavage compared with no administration of PAE in vitro. Proliferation of splenocyte and thymocyte cells was also significantly enhanced in chickens administered 1.25, 2.5, 5, and 10 mg/kg of PAE for 5 wk. In experiment 2, proliferation of peripheral blood mononuclear cells, splenocytes, and thymocytes in chickens administered PAE for 6 wk was continuously higher than that in other groups. Additionally, increasing cell populations for which CD4⁺CD8^-(Th cells) and Bu-1⁺ (B cells) protein was expressed on the cell surface were significantly different after 4 wk of PAE administration in chickens. Thus, the immunomodulatory effects of a PAE from P. radiata bark differed by dosing period in chickens.