Dietary glutathione supplementation attenuates oxidative stress and improves intestinal barrier in diquat-treated weaned piglets

The aim of this study was to investigate the protective effects of glutathione (GSH) against oxidative stress and intestinal barrier disruption caused by diquat (an oxidative stress inducer) in weaned piglets. Twenty-four piglets were randomly assigned to four treatments with six pigs per treatment for an 18-d trial. Treatments were basal diet, basal diet + diquat challenge, 50 mg/kg GSH diets + diquat challenge and 100 mg/kg GSH diets + diquat challenge. On day 15, piglets in basal diet group and diquat-challenged groups were intraperitoneally injected with sterile saline and diquat at 10 mg/kg body weight, respectively. The results showed that GSH supplementation improved growth performance of diquat-injected piglets from days 15 to 18 (p < 0.05), especially at a dose of 100 mg/kg GSH. Meanwhile, diquat also caused oxidative stress and intestinal barrier damage in piglets. However, GSH supplementation enhanced the antioxidant capacity of serum and jejunum, as evidenced by the increase in GSH content and total superoxide dismutase activities and the decrease in 8-hydroxy-2'-deoxyguanosine concentrations (p < 0.05). GSH also up-regulated the mRNA expressions of intestinal tight junction protein (zonula occludens 1, ZO1; occludin, OCLN; claudin-1, CLDN1) and mitochondrial biogenesis and function (peroxisome proliferator-activated receptor-gamma coactivator-1 alpha, PGC1α; mitochondrial transcription factor A, TFAM; cytochrome c, CYCS), compared with diquat-challenged piglets in basal diet (p < 0.05). Thus, the study demonstrates that GSH protects piglets from oxidative stress caused by diquat and 100 mg/kg GSH has a better protective role.