Effect of astaxanthin from Phaffia rhodozyma on T cell population and responsiveness to mitogen in splenic mononuclear cells of male broiler chicks.

摘要

Chicks, 1-week-old, were fed ad libitum diets containing 0, 20 or 100 ppm Ax for 7 days. It was observed that Ax decreased the percentage of CD3-positive cells, an indicator of the T cell population in splenic lymphocytes. Diet with 20 ppm Ax decreased the percentage of CD4-positive cells estimated as the indicator of helper T cells, but no modulation was observed by feeding 100 ppm Ax diet. The percentage of CD8-positive cells, an indicator of cytotoxic T cell, was not affected by diets containing either 20 or 100 ppm Ax. T cell proliferation stimulated with Con A was enhanced by feeding diet containing 20 ppm Ax, but not affected by 100 ppm Ax. Feeding diets containing 20 and 100 ppm Ax enhanced the proliferation of splenocytes against PHA. Diets containing Ax had no effect on interleukin (IL)-2 mRNA expression in splenocytes stimulated by Con A estimated as the T cell proliferation promoting factor. IL-2 like activity was slightly, but was significantly decreased by 20 ppm Ax. IFN- gamma mRNA expression, estimated as a T cell activator under condition of Con A stimulation, was higher in chicks fed with 20 ppm Ax. These results suggest that proliferation and cytokine expressions of splenic T cells in response to feeding Phaffia rhodozyma containing Ax were independent of the dietary Ax concentration or total Ax intake. The enhancement of T cell proliferation by 20 ppm Ax might be caused by the changes in IFN- gamma rather than IL-2 production in the chick splenocytes..