The effects of feeding Fusarium moniliforme M-1325 culture material (CM), grown under different environmental conditions, were studied in turkey poults. Poults were fed a control diet or diets containing four levels of FB1 (75, 150, 225, or 300 mg/kg) prepared from F. moniliforme M-1325 cultures that produced 7800 (CM1) or 4000 mg FB1/kg (CM2). F. moniliforme M-1325 CM that produced a low concentration of FB1 (350 mg FB1/kg) was also used to prepare an additional diet containing 75 mg FB1/kg (CM3). Dose-dependent decreases in feed intake and body-weight gains and dose-dependent increases in liver weights and serum sphinganine (SA) to sphingosine (SO) ratios were observed in poults fed CM1 or CM2. Poults fed CM3 consumed more feed and had lower body-weight gains than controls or poults fed CM1 or CM2 (at 75 mg FB1/kg). Poults fed CM3 also had increased liver weights and SA:SO ratios compared with control poults. Generalized hepatocellular hyperplasia was observed in all FB1 treatment groups. Biliary hyperplasia was evident in turkeys fed 150 to 300 mg FB1/kg. Results indicate that at equivalent dietary FB1 levels, F. moniliforme cultures producing different concentrations of FB1 differ in their effects on turkey poults.