In this study, 160 day-old, Japanese quail chicks were randomly assigned into four groups, 40 birds of each. The first control group was fed on a basal diet (group1) and the other 3 groups were fed basal diet supplemented with 0.5% yeast, 0.5% yeast + 200mg fumincin-B1/ kg diet and 200mg fumincin-B1/ kg diet, respectively. The results of fumincin-B1(FBI) supplemented group showed a significant on increase in mortality rate, alanine amonotransferase (ALT), aspartate aminotransferase (AST), cholesterol, uric acid and createnine and a decrease in body weight,hatchability, fertility and hatching weight, hematological parameters, serum total proteins, globulins and glutathioneperoxidase (GPx) activity in comparison with the control group. Yeast supplementation was found to alleviate the toxic effects of FB1.