Effects of Dietary Selenium on Histopathological Changes and T Cells of Spleen in Broilers Exposed to Aflatoxin B1

Aflatoxin B-1 (AFB(1)), which causes hepatocellular carcinoma and immune-suppression, is commonly found in feedstuffs. To evaluate the ability of selenium (Se) to counteract the deleterious effects of AFB(1), two hundred 1-day-old male avian broilers, divided into five groups, were fed with basal diet (control group), 0.3 mg/kg AFB(1) (AFB(1) group), 0.3 mg/kg AFB(1)+0.2 mg/kg Se (+Se group I), 0.3 mg/kg AFB(1)+0.4 mg/kg Se (+Se group II) and 0.3 mg/kg AFB(1)+0.6 mg/kg Se (+Se group III), respectively. Compared with control group, the relative weight of spleen in the AFB(1) group was decreased at 21 days of age. The relative weight of spleen in the three +Se groups was higher than that in the AFB(1) group. By pathological observation, the major spleen lesions included congestion in red pulp and vacuoles appeared in the lymphatic nodules and periarterial lymphatic sheath in the AFB(1) group. In +Se groups II and III, the incidence of major splenic lesions was decreased. The percentages of CD3+, CD3+CD4+ and CD3+CD8+ T cells in the AFB(1) group were lower than those in control group from 7 to 21 days of age, while there was a marked increase in the three +Se groups compared to the AFB(1) group. The results indicated that sodium selenite could improve the cellular immune function impaired by AFB(1) through increasing the relative weight of spleen and percentages of splenic T cell subsets, and alleviating histopathological spleen damage.