Sodium selenite prevents suppression of mucosal humoral response by AFB₁ in broiler's cecal tonsil

Aflatoxin B₁ (AFB₁), the most common mycotoxin in human food and animal feed, produces hepatotoxic, genotoxic and immunosuppressive effects in multiple species. Selenium (Se) has emerged as an important element in the dietary prevention of various toxic agents. The present study was designed to scrutinize the protective effects of sodium selenite on the histological lesions and suppression of mucosal humoral response in the cecal tonsil generated by AFB₁. A total of 156 one-day-old broilers were divided into four groups and fed on basal diet (control group), 0.6 mg/kg AFB₁ (AFB₁ group), 0.4 mg/kg Se supplement (+Se group), and 0.6 mg/kg AFB₁ + 0.4 mg/kg Se supplement (AFB₁+Se group) respectively for 21 days. Our results showed that 0.4 mg/kg Se supplement in broiler's diets could improve the AFB₁-induced histological lesions in the cecal tonsils including the depletion of lymphocytes in the lymphatic nodules as well as the shedding of microvilli in the absorptive cells. Moreover, Se could restore the decreased number of IgA+ cells and expression levels of pIgR, IgA, IgG, and IgM mRNA induced by AFB₁ to be close to those in the control group. These results demonstrated that 0.4 mg/kg supplemented dietary Se in the form of sodium selenite could protect the cecal tonsils from the histological lesions and suppression of the mucosal humoral response provoked by 0.6 mg/kg AFB₁. Our study may provide new experimental evidences for better understanding of AFB₁-induced damage of mucosal immunity and protective effect of Se against this toxin.