Weaning disrupts intestinal antioxidant status, impairs intestinal barrier and mitochondrial function, and triggers mitophagy in piglets.

In the present study, we investigated the influence of weaning on antioxidant status, intestinal integrity, mitochondrial function, and the mitophagy level in piglets (weaned at 21 d) during the 1 wk after weaning. The redox status was measured by antioxidant enzymes activities, related genes expression, and malondialdehyde (MDA) content in jejunum. The intestinal barrier function was assessed by the Ussing chamber and expression of tight junction proteins in the jejunum. The function of intestine mitochondria was measured by mitochondrial DNA (mtDNA) content and activities of mitochondria oxidative phosphorylation complexes. The levels of light chain 3-1 (LC3-I), light chain 3-II (LC3-II), PTEN-induced putative kinase 1 (PINK1), and Parkin were determined to investigate whether mitophagy is involved in the weaning process. The results showed that, as compared with the preweaning phase (d 0), weaning suppressed (P < 0.05) the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) on d 3 and d 7 postweaning, decreased (P < 0.05) the expression of copper and zinc superoxide dismutase (Cu/Zn-SOD), manganese-containing superoxide dismutase (Mn-SOD) on d 3 postweaning, declined (P < 0.05) the level of glutathione peroxidase 1 (GPX-1) and glutathione peroxidase 4 (GPX-4) on d 3 and d 7 postweaning, and increased (P < 0.05) MDA content in jejunum on d 3 and d 7 postweaning. The jejunal transepithelial electrical resistance and levels of occludin, claudin-1, and zonula occludens-1 on d 3 and d 7 postweaning were reduced (P < 0.05), and paracellular flux of fluorescein isothiocyanatedextran (4 kDa) on d 3 and d 7 postweaning was increased (P < 0.05). Weaning induced mitochondrial dysfunction, as demonstrated by decreased (P < 0.05) content of mtDNA on d 3 and d 7 postweaning and declined (P < 0.05) activities of mitochondria complexes (I, II, III, IV) in jejunum on d 1, d 3, and d 7 postweaning. Weaning led to an increased (P < 0.05) expression level of mitophagy-related proteins, PINK1 and Parkin, in the intestinal mitochondria, as well as an enhancement (P < 0.05) of the ratio of LC3-II to LC3-I content in the jejunal mucosa on d 1, d 3, and d 7 postweaning. These results suggest that weaning disrupted intestinal oxidative balance, and this imbalance may impair intestinal barrier and mitochondrial function and trigger mitophagy in piglets.

Influences of Copper/Zinc-Loaded Montmorillonite on Growth Performance, Mineral Retention, Intestinal Morphology, Mucosa Antioxidant Capacity, and Cytokine Contents in Weaned Piglets.

The effects of copper/zinc-loaded montmorillonite (Cu/Zn-Mt) on growth performance, mineral retention, intestinal morphology, mucosa antioxidant capacity, and cytokine contents in weaned piglets were investigated in the present study. One hundred eight piglets weaned at 21 ± 1 days of age (Duroc × Landrace× Yorkshire; average initial weight of 6.36 kg) were allotted to three treatments for 2 weeks. The three treatments were as follows: (1) control group: basal diet; (2) Cu/Zn-Mt group: basal diet + 39 mg/kg Cu and 75 mg/kg Zn as Cu/Zn-Mt; (3) Cu + Zn + Mt group: basal diet + mixture of CuSO4, ZnSO4, and Mt (equal amount of Cu, Zn, and Mt to the Cu/Zn-Mt group). Each treatment had six pens of six piglets. The results showed that as compared with the control group and the Cu + Zn + Mt group, Cu/Zn-Mt supplementation increased (P < 0.05) the average daily gain and the gain/feed ratio; Cu/Zn-Mt supplementation increased (P < 0.05) the Cu and Zn concentrations in serum, jejunum, and ileum mucosa, villus height, the ratio of villus height to crypt depth, and the activities of SOD, GSH-Px, and IL-10 levels, and decreased the malondialdehyde concentrations in the jejunum and ileum, and intestinal IL-1ß, IL-6, and TNF-α levels. Moreover, supplementation with the mixture of CuSO4, ZnSO4, and Mt had no effect on the growth performance, but increased the mucosa Cu and Zn concentrations, intestinal morphology, antioxidant capacity, and immune function in the duodenum, while it had no effect on the above indexes in the jejunum and ileum. The results indicated that Mt could be used as a controlled carrier for Cu and Zn, which made Cu/Zn-Mt have better biological activities in the intestine than the mixture of Cu, Zn, and Mt.