This study aims to investigate the effects of exposure to different dosages of zearalenone (ZEA) on cecal physical barrier functions and its mechanisms based on the TGF-β1/Smads signaling pathway in weaned piglets. Thirty-two weaned piglets were allotted to four groups and fed a basal diet supplemented with ZEA at 0, 0.15, 1.5, and 3.0 mg/kg, respectively. The results showed that 1.5 and 3.0 mg/kg ZEA damaged cecum morphology and microvilli, and changed distribution and shape of M cells. Moreover, 1.5 and 3.0 mg/kg ZEA decreased numbers of goblet cells, the expressions of TFF3 and tight junction proteins, and inhibited the TGF-β1/Smads signaling pathway. Interestingly, the 0.15 mg/kg ZEA had no significant effect on cecal physical barrier functions but decreased the expressions of Smad3, p-Smad3 and Smad7. Our study suggests that high-dose ZEA exposure impairs cecal physical barrier functions through inhibiting the TGF-β1/Smads signaling pathway, but low-dose ZEA had no significant effect on cecum morphology and integrity through inhibiting the expression of smad7. These findings provide a scientific basis for helping people explore how to reduce the toxicity of ZEA in feeds.
Keywords: TGF-β1/Smads; cecum; physical barrier; piglet; zearalenone.