Effects of increasing dietary zinc oxide levels on parameters of intestinal and renal mitochondrial energy metabolism and antioxidant system, and intestinal inflammation in weaned piglets

This study examined the effects of increasing dietary zinc oxide (ZnO) levels on intestinal and kidney mitochondrial metabolism and oxidative balance in weaned pigs. One hundred twenty weaned piglets were assigned to three experimental diets: 100, 1000 and 3000 mg Zn/kg. Piglets were slaughtered on d21 (weaning), 23, 35 or 42 for small intestine and kidney samples collection. Mitochondrial concentrations of Zn and Cu, mitochondrial respiration, antioxidant activities, inflammatory response and related genes expression were analyzed. Piglets fed 3000Zn had the highest mitochondrial zinc concentrations in both tissues (P < 0.001). The lowest mitochondrial copper concentrations in both tissues were detected for 100Zn at d35 (P ≤ 0.007). Jejunal mitochondrial superoxide dismutase activity was higher in 3000Zn compared to 100Zn piglets (P = 0.019). Mitochondrial glutathione peroxidase activity was not affected by treatments (P = 0.113). The jejunum mucosa mRNA expression of most antioxidant and innate immunity response-related genes was lower for 3000Zn piglets (P ≤ 0.013). No effect on mitochondrial respiration and antioxidant response was detected in kidney (P ≥ 0.193). In conclusion, increasing dietary ZnO levels affected mitochondrial zinc and copper homeostasis with impacts on energy metabolism, the antioxidant system, and the innate immune response in post-weaning piglets.