Changes in cecal morphology, cell proliferation, antioxidant enzyme, volatile fatty acids, lipopolysaccharide, and cytokines in piglets during the postweaning period

Qingqing Deng, Xian Tan, Huiru Wang, Qiye Wang, Pengfei Huang, Yali Li, Jianzhong Li, Jing Huang, Huansheng Yang, Yulong Yin

Weaning stresses often induce markedly structural and functional changes in the small intestine. However, little data are available on the changes of the morphology, function, and health in the cecum of piglets post-weaning. This study was conducted to measure the effects of weaning on the cecum in piglets. Forty piglets were weaned at 21 d and samples were collected at different time points (d 0, 1, 3, 7, and 14) post-weaning. The crypt depth, crypt width, and total epithelial cell numbers increased on d 7 and 14, compared to d 0, 1, and 3 (P< 0.001). The value of Ki67/total epithelial cells was highest on d 0 compared to all other days (P< 0.05). Besides, a higher concentration of malondialdehyde (MDA) was observed on d 3 (P < 0.001). The activity of CuZn-superoxide dismutase (CuZn-SOD; P< 0.05) enhanced from d 0 to 1 and the activity of catalase (CAT) increased from d 1 to 3 (P < 0.001). In addition, d 3, 7, and 14 had greater acetic, propanoic and butyric acid contents than on d 1 (P < 0.001). The pH and monocarboxylate transporter 1 (MCT1) expression increased from d 0 to 1 and from d 3 to 7 and decreased between d 1 and 3 (P< 0.001). The mRNA expression of solute carrier family 9 member A3 (SLC9A3) decreased on d 1 compared to all other post-weaning days (P < 0.05). The abundance of toll-like receptor 4 (TLR4) and interferon-γ (IFN-γ) mRNA expression increased (P< 0.05) during the first 24 h after weaning. The concentration of lipopolysaccharide (LPS) increased from d 3 to 7, then decreased on d 14 (P< 0.05). The mRNA expression of tumor necrosis factor-α (TNF-α) enhanced from d 7 to 14 (P< 0.05). The abundance of phosphorylated mammalian target of rapamycin (p-mTOR) protein was lower on d 14 than d 0 (P< 0.05). Taken together, these results show that weaning in piglets influences intestinal morphology, function and health in the cecum.