Zearalenone enhances reproductive tract development, but does not alter skeletal muscle signaling in prepubertal gilts

Zearalenone is a potent mycotoxin that has estrogenic properties. In vitro results indicate that zearalenone metabolites down-regulate proteins associated with protein synthesis (protein kinase B, Akt) and cellular proliferation (extracellular signal-regulated kinase, ERK). The objectives of this study were to determine the effect of zearalenone on (1) growth performance and signaling for protein synthesis, and (2) reproductive tract development. At 28 d of age, gilts were randomly assigned to consume a commercial basal diet (C) or C+1.5 mg/kg zearalenone (n = 10) for 4 wk, at which time gilts were euthanized, urine collected, and tissue collected. No differences were observed in average daily gain, average daily feed intake, or gain:feed (P>0.28). Reproductive tract weight (2.4-fold) and uterine endometrial gland development (50%) were increased in zearalenone fed gilts (P<0.01). In uterus, estrogen receptor (ER)-α expression was unchanged (P>0.28), but gilts consuming zearalenone had 2.0- and 3.5-fold higher abundance of ER-β mRNA and protein, respectively (P<0.01). No differences were observed in Akt, mammalian target of rapamycin, or ERK abundance or phosphorylation in muscle (P>0.36). Zearalenone had no effect on growth performance or skeletal muscle signaling in prepubertal gilts, but zearalenone increased reproductive tract size and glandular development, possibly due, in part, to altering the expression of ER-β.