Bile acids (BAs) are crucial for maintaining intestinal epithelial homeostasis. However, the metabolic changes in BAs and the communication between intestinal epithelial cells (IECs) in infants after birth remain unclear. This study aims to elucidate the BA profiles of newborn piglets (NPs) and suckling piglets (SPs), and to investigate their regulatory effects on IEC proliferation and barrier integrity, as well as the potential underlying mechanisms. In this study, compared with NPs, there were significant increases in serum triglycerides, total cholesterol, glucose, and albumin levels for SPs. The total serum BA content in SPs exhibited an obvious increase. Moreover, the expression of BA synthase cytochrome P450 27A1 (CYP27A1) was increased, and the ileal BA receptor Takeda G-coupled protein receptor 5 (TGR5) and proliferation marker Ki-67 were upregulated and showed a strong positive correlation through a Spearman correlation analysis, whereas the expression of farnesoid X receptor (FXR) and occludin was markedly downregulated in SPs and also revealed a strong positive correlation. These findings indicate that the increased synthesis and metabolism of BAs may upregulate TGR5 and downregulate FXR to promote IEC proliferation and influence barrier function; this offers a fresh perspective and evidence for the role of BAs and BA receptors in regulating intestinal development in neonatal pigs.
Keywords: FXR; TGR5; bile acid metabolism; cell proliferation; intestinal barrier function; suckling piglets.