Dietary ferulic acid supplementation enhances antioxidant capacity and alleviates hepatocyte pyroptosis in diquat challenged piglets

Abstract

Background: Oxidative stress significantly impacts growth performance and liver function in piglets. Ferulic acid (FA) works as an antioxidant, however, the role and mechanism of FA in the regulation of diquat-induced oxidative stress in piglets are less known. This study was designed to investigate the effects of FA on growth performance and antioxidant capacity in piglets with diquat challenge.

Methods: Thirty-two healthy DLY (Duroc × Landrace × Yorkshire) piglets (13.24 ± 0.19 kg) were randomly divided into one of two diets including 0 or 4 g/kg FA for 14 d. On d 15, all pigs were intraperitoneally injected diquat or sterile saline.

Results: Dietary supplementation with ferulic acid (FA) significantly improved the average daily gain (ADG) and decreased feed-gain ratio (F/G) of piglets. Here, dietary FA supplementation reduced serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) activities in diquat challenged piglets. Furthermore, diquat infusion increased reactive oxygen radicals (ROS) level in liver, decreased the activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC) and increased malondialdehyde (MDA) content in the liver and serum. Supplementation with FA significantly increased T-AOC and T-SOD activities and decreased MDA and ROS levels. FA down-regulated gene and protein expression of Keap1, and up-regulated protein expression of Nrf2 and HO-1 in the liver of piglets with diquat challenge. Importantly, diquat challenge increased the ratio of late apoptosis, increased serum levels of IL-1β, IL-18 and lactate dehydrogenase (LDH), and up-regulated pyroptosis-related genes in the liver. FA supplementation reduced the ratio of late apoptosis and down-regulated mRNA expression of Caspase-1. Accordingly, FA addition reduced concentration of IL-1β, IL-18, and LDH under diquat challenge.

Conclusions: Diquat-induced oxidative stress reduced growth performance and impaired liver function in piglets. Dietary FA supplementation enhanced the antioxidant capacity and reduced the degree of hepatocyte pyroptosis, thereby alleviating the oxidative damage in the liver and mitigating the impact of diquat on growth performance of piglets.

Keywords: Antioxidant capacity; Ferulic acid; Hepatic pyroptosis; Piglets.

Fig. 1

Effects of FA supplementation on hepatic injury in piglets. A–D 100 × ; a–d 200 × ; A and a Control group; B and b FA group; C and c Diquat-challenged group; D and d Diquat-challenged group supplemented with FA. ALT: alanine aminotransferase; AST: aspartate aminotransferase. Data are expressed as the means plus SEM (n = 8). ^*P < 0.05, ^**P < 0.01

Fig. 2

Effects of FA supplementation on antioxidant related indexes of piglets. A–D The levels of T-SOD, GSH-Px, T-AOC and MDA in serum. E–H The levels of T-SOD, GSH-Px, T-AOC and MDA in the liver. Data are expressed as the means plus SEM (n = 8). ^*P < 0.05, ^**P < 0.01

Fig. 3

Relative expression levels of antioxidant-related proteins in the liver. A and B Protein abundance of Keap1, Nrf2, HO-1 and NQO1 in the liver. Data are expressed as the means plus SEM (n = 8). ^*P < 0.05, ^**P < 0.01

Fig. 4

Effects of FA supplementation on the liver ROS level and apoptosis in the piglets. A and C Flow cytometry analysis of ROS in the liver; B, D, and E Flow cytometry analysis of apoptosis, proportion of apoptotic cells in early period (D) and in late period (E) in the liver. Data are expressed as the means plus SEM (n = 8). ^*P < 0.05, ^**P < 0.01

Fig. 5

Effects of FA supplementation on serum LDH and cytokine concentrations in piglets. A The levels of LDH in serum; B and C The concentrations of IL-1β and IL-18 in serum. Data are expressed as the means plus SEM (n = 8). ^*P < 0.05, ^**P < 0.01