Selenium Rescues Aflatoxin B1-Inhibited T Cell Subsets and Cytokine Levels in Cecal Tonsil of Chickens

Cecal tonsil is the largest peripheral lymphoid organ of the gut-associated lymphoid tissue executing immune function. To evaluate the protective effect of selenium (Se) on the cecal tonsil of chicken exposed to aflatoxin B-1 (AFB(1)), 144 1-day-old healthy Cobb chickens were randomly divided into four groups, and fed with basal diet (control group), 0.6mg/kg AFB(1) (AFB(1) group), 0.4mg/kg Se supplement (+Se group), and 0.6mg/kg AFB(1)+0.4mg/kg Se supplement (AFB(1)+Se group) for 21days, respectively. The results showed that AFB(1) significantly decreased the percentages of CD3(+), CD3(+)CD4(+), CD3(+)CD8(+) T cells, and the CD4(+)/CD8(+) ratio, and suppressed the expressions of IL-2, IL-4, TNF-, and IFN- mRNA in the cecal tonsil. However, Selenium (Se) supplied in the diets restored the percentages of T cell subsets, the CD4(+)/CD8(+) ratio, and mRNA expressions of cytokines in the AFB(1) group to be close to those in the control group, and did not exhibit obvious toxicity to the cecal tonsil. These results indicated that Se exerted protective effect against AFB(1) on the functions of cecal tonsil, and also partially uncovered a new role of Se that could protect cecal tonsil of chickens from immunotoxicity of AFB(1).