EN
The purpose of this stud) was to establish the pathomorphological alterations in the lymphatic organs of broiler chickens fed forages containing fumonisin B1 (FB1), known to cause immunodeficiency. The birds were treated with mycotoxin isolated from corn contaminated with F. verticilloides (moniliforme). Apoptotic and necrotic changes were recorded under light and electron microscopes. Significant morphological alterations such as focal necrosis and an increased number of apoptotic lymphocytes and epithelial cells were found mainly in the thymus and spleen, while the bursa Fabricii was less affected. It can be concluded that FB1 causes in vivo suppression of development, differentiation, and function of the lymphoid cells and the stromal epithelial reticular cells, and activates the processes leading to cell death in organs of the immune system of chickens.