Effect of Vanadium on the Subset and Proliferation of Peripheral Blood T Cells, and Serum Interleukin-2 Content in Broilers

The purpose of this 42-day study was to investigate the effects of dietary excess vanadium on immune function by determining changes of the subsets and proliferation function of peripheral blood T cells. Four hundred twenty 1-day-old avian broilers were divided into six groups and fed on a corn-soybean basal diet as control diet or the same diet amended to contain 5, 15, 30, 45, and 60 ppm vanadium supplied as ammonium metavanadate. In comparison with those of the control group, the percentages of CD (3) (+) , CD (3) (+) CD (4) (+) , and CD (3) (+) CD (8) (+) were decreased in 45 and 60 ppm groups from 14 to 42 days of age, and the percentages of CD (3) (+) and CD (3) (+) CD (4) (+) were increased in 5 ppm group at 42 days of age. The CD (4) (+) /CD (8) (+) ratio was increased in 45 and 60 ppm groups at 28 days of age. Meanwhile, the proliferation function of peripheral blood T cell were decreased in 30, 45, and 60 ppm groups from 14 to 42 days of age. Also, the serum interleukin-2 contents were decreased in 45 and 60 ppm groups from 14 to 42 days of age and increased in 5 ppm group at 28 days of age. Histopathologically, hypocellularity appeared in the thymus in 45 and 60 ppm groups. It was concluded that dietary vanadium in excess of 30 ppm reduced the percentages of peripheral blood T-cell subsets and the proliferation function and serum interleukin-2 contents. The cellular immune function was finally impaired in broilers.