Effects of Dietary Epidermal Growth Factor Supplementation on Liver Antioxidant Capacity of Piglets with Intrauterine Growth Retardation.

Abstract

The present experiment was conducted to study the effects of dietary epidermal growth factor (EGF) supplementation on the liver antioxidant capacity of piglets with intrauterine growth retar-dation (IUGR). The present study consists of two experiments. In experiment 1, six normal-birth-weight (NBW) and six intrauterine growth retardation (IUGR) newborn piglets were slaughtered within 2 to 4h after birth to compare the effects of IUGR on the liver antioxidant capacity of new-born piglets. The results showed that compared with NBW piglets, IUGR piglets had a lower birth weight and liver relative weight; IUGR piglets had a higher serum malondialdehyde (MDA) level, liver MDA level and hydrogen peroxide (H2O2) level, and had a lower liver total antioxidant capacity (T-AOC) level and glutathione peroxidase (GSH-Px) activity; IUGR trended to increase se-rum alanine aminotransferase (ALT) activity, aspartate aminotransferase (AST) activity, and H2O2 level, and trended to decrease liver total superoxide dismutase (SOD) activity. In experiment 2, six NBW piglets, and 12 IUGR piglets weaned at 21 days of age were randomly divided into the NC group (NBW piglets fed with basal diet); IC group (IUGR piglets fed with basal diet), and IE group (IUGR piglets fed with basal diet plus 2mg/kg EGF), and feeding for 14 days. Organ index, serum parameters, liver antioxidant capacity, and liver antioxidant-related genes expression were measured. The results showed that compared to the IC group, dietary EGF supplementation (IE group) significantly reduced serum MDA level and H2O2 level, and liver protein carbonyl (PC) level and 8-hydroxydeoxyguanosine (8-OHDG) level of piglets with IUGR; dietary EGF supplementation (IE group) significantly increased serum T-AOC level, liver T-AOC level and GSH-Px activity; dietary supplemented with EGF (IE group) enhanced liver Nrf2, NQO1, HO1, and GPX1 mRNA expression compared to IC group. Pearson's correlation analysis further showed that EGF can alleviate liver oxidative injury caused by IUGR and improve the performance of IUGR piglets. In conclusion, EGF exhibited potent protective effects on IUGR induced liver oxidative injury, by activating the Nrf2 signaling pathway to mediate the expression of downstream antioxidant enzymes and phase II detoxification enzymes (NQO1 and HO1), thereby alleviating liver oxidative damage and promoting the growth performance of IUGR piglets.