Simple SummaryMycotoxin-contaminated feed is a current, worldwide problem. Mold-contaminated cereal is rich in heat-resistant and harmful metabolites such as fumonisins. The amount of fumonisins consumed as part of animal feed, including livestock feed, is unknown, and thus their influence on animal health, the costs associated with veterinary health care and the associated economic losses in breeding are impossible to calculate. Prenatal exposure of fetuses to fumonisins, through exposure of the mothers to fumonisins during pregnancy, is an important problem during breeding, often resulting in disturbed development of offspring in the postnatal period as a result. Thus, studies focused on the effects of fumonisin-exposure during the prenatal period on postnatal development are required.AbstractAnimal feed is very frequently contaminated with different types of mold, the metabolites of which are toxic to living organisms. Mold-contaminated cereal is rich in heat-resistant and harmful metabolites such as fumonisins (FBs). The amount of FBs consumed as part of animal feed, including livestock feed, is unknown. Therefore, this study aimed to evaluate the effects of maternal oral FB intoxication on basal duodenum morphology and the immunolocalization of gut hormones responsible for food intake (leptin and ghrelin), as well as their receptors, in newborn rat offspring. Pregnant Wistar rats were randomly allocated to one of three groups: a control group or one of two FB-intoxicated groups (60 or 90 mg FB/kg b.w., respectively). Basal morphological duodenal parameters changed in a dose- and sex-dependent manner. The intensity of the ghrelin immunoreaction was unchanged in females, while in males it increased after FB exposure (60 mg/kg b.w.), with a simultaneous decrease in expression of the ghrelin receptor. Leptin and its receptor immunoreaction intensity was decreased in both sexes following FB exposure. The current study highlighted the potential involvement of intestinal ghrelin and leptin in the metabolic disturbances observed later in life in offspring that were prenatally exposed to fumonisins.