RESUMEN
Ergot alkaloids, a class of mycotoxins, induce vasoconstriction when consumed by animals and humans. Pregnant ewes (n = 16; 81.2 kg ± 7.7) were assigned fed endophyte-infected tall fescue seed (E+; 4.14 µg ergovaline + ergovalinine/g seed) or a control diet (CON; 0 µg ergovaline + ergovalinine) for increasing duration during late gestation (from gd86 to gd110 or gd133) to examine changes in placentome morphology and mRNA transcriptome, and fetal development. Exposure to E+ fescue reduced serum prolactin concentrations at gd110 and gd133 demonstrating treatment efficacy. For control ewes, cotyledon and total placentome weights decreased with advancing gestation due to remodeling of placental tissues; however, cotyledon and placentome weight did not change with advancing gestation in E+ fed ewes. Fetal brain sparing was evident in E+ exposed fetuses at gd110 and gd133 compared to CON, which demonstrates asymmetrical growth and intrauterine growth restriction. Mycotoxin exposure (E+) resulted in differential expression of 22 genes in the cotyledon tissue at gd110 but only one gene at gd133 compared to CON. These results suggest that the response to mycotoxin exposure in the pregnant sheep model has an immediate impact on placental remodeling and fetal development that persists throughout the duration of the exposure period.