The Zinc Concentration in the Diet and the Length of the Feeding Period Affect the Methylation Status of the ZIP4 Zinc Transporter Gene in Piglets

PLoS One. 2015 Nov 23;10(11):e0143098. doi: 10.1371/journal.pone.0143098. eCollection 2015.

Abstract

High doses of zinc oxide are commonly used in weaned pig diets to improve performance and health. Recent reports show that this may also lead to an imbalanced zinc homeostasis in the animal. For a better understanding of the regulatory mechanisms of different zinc intakes, we performed a feeding experiment to assess potential epigenetic regulation of the ZIP4 gene expression via DNA methylation in the small intestine of piglets. Fifty-four piglets were fed diets with 57 (LZn), 164 (NZn) or 2,425 (HZn) mg Zn/kg feed for one or four weeks. The ZIP4 expression data provided significant evidence for counter-regulation of zinc absorption with higher dietary zinc concentrations. The CpG +735 in the second exon had a 56% higher methylation in the HZn group compared to the others after one week of feeding (8.0·10-4 < p < 0.035); the methylation of this CpG was strongly negatively associated with the expression of the long ZIP4 transcripts (p < 0.007). In the LZn and NZn diets, the expression of the long ZIP4 transcripts were lower after four vs. one week of feeding (2.9·10-4 < p < 0.017). The strongest switch leading to high DNA methylation in nearly all analysed regions was dependent on feeding duration or age in all diet groups (3.7·10-10 < p < 0.099). The data suggest that DNA methylation serves as a fine-tuning mechanism of ZIP4 gene regulation to maintain zinc homeostasis. Methylation of the ZIP4 gene may play a minor role in the response to very high dietary zinc concentration, but may affect binding of alternate zinc-responsive transcription factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Binding Sites
  • Cation Transport Proteins / genetics*
  • Cation Transport Proteins / metabolism
  • CpG Islands / genetics
  • DNA Methylation / genetics*
  • Diet*
  • Epithelium / metabolism
  • Feeding Behavior*
  • Jejunum / metabolism
  • Protein Binding
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Sus scrofa / genetics*
  • Time Factors
  • Transcription Factors / metabolism
  • Zinc / analysis*
  • Zinc / pharmacology

Substances

  • Cation Transport Proteins
  • RNA, Messenger
  • Transcription Factors
  • Zinc

Grants and funding

The study was funded by the Deutsche Forschungsgemeinschaft (DFG, http://www.dfg.de/en/) through grant SFB 852 (http://www.sfb852.de/en/) with JZ as the Speaker of the SFB 852. The DFG had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Epiontis GmbH provided support in the form of salaries for authors [UB, SO], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the "author contributions" section.