Illicium verum and Eucommia ulmoides leaf extracts promote nutrient availability and antioxidant capacity in piglets by upregulating duodenal and jejunal Nrf2/TNF-α.

The effect of Illicium verum extracts (IVE) or Eucommia ulmoides leaf extracts (ELE) on nutrient availability, duodenal and jejunal antioxidant ability of Duroc ×Landrace × Yorkshire (DLY) and Chinese native Licha-black (LCB) piglets was investigated. Ninety-six piglets (48 DLY and 48 LCB respectively) without significant difference in body weight (11.22 ± 0.32 kg) were used in a 2 × 4 factorial design. Animals were randomly allocated to four treatments, and each had four replicates with three DLY and three LCB piglets. Treatments were basal diet (CON) and basal diet with 500 mg/kg IVE, 250 mg/kg ELE and 50 mg/kg chlortetracycline (CHL) respectively. Animals were placed individually for 7-days adaptation following 42-days test. Results showed the significant interaction (p < 0.05) between dietary treatments and pig species in activity of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px), content of malondialdehyde (MDA), and α-tumour necrosis factor (TNF-α), nuclear factor erythroid 2-related factor 2 (Nrf2) and Nrf2/TNF-α at mRNA and protein level in duodenum and jejunum of DLY and LCB piglets. The IVE and ELE increased (p < 0.05) activity of GSH-Px and T-SOD, and the Nrf2/TNF-α at mRNA and protein level, however, the decreased (p < 0.05) MDA content, and TNF-α at mRNA and protein level in duodenum and jejunum were observed. The CHL decreased (p < 0.05) activity of GSH-Px and T-SOD, TNF-α and Nrf2 at mRNA and protein level in duodenum, but increased (p < 0.05) MDA content and Nrf2/TNF-α in jejunum. DLY piglets had higher (p < 0.05) nutrient digestibility (organic matter, crude protein and gross energy), availability (biological value and net protein utilization), MDA content, and TNF-α at mRNA and protein level in jejunum, and had lower (p < 0.05) activity of GSH-Px and T-SOD, and Nrf2 and Nrf2/TNF-α at mRNA and protein level in duodenum and jejunum than LCB. In conclusion, the 500 mg/kg IVE and 250 mg/kg ELE improved the nutrient availability, and the improvement of antioxidant capacity is realized by activating the Nrf2/TNF-α of duodenum and jejunum. The CHL had adverse effects on antioxidant ability of DLY and LCB piglets. The results showed that the nutrient digestion and absorption capacity of DLY were stronger than that of LCB piglets, but the antioxidant capacity was lower than that of LCB piglets. Therefore, the IVE and ELE are recommended as a new potential alternative to antibiotics in piglets' diets.

Illicium verum extracts and probiotics with added glucose oxidase promote antioxidant capacity through upregulating hepatic and jejunal Nrf2/Keap1 of weaned piglets.

Accumulating evidences indicate that plant extracts and probiotics are effective antioxidant substitutes which play important roles in animal production. However, the comparative study of the mechanism underlying the antioxidant property of Illicium verum extracts (IVE) and probiotics with added glucose oxidase (PGO) on piglets remains to be explored. This study evaluated the difference and the interaction effect of IVE and PGO on serum, liver, and jejunum antioxidant capacity of weaned piglets. A total of 32 weaned piglets (Duroc × Landrace × Yorkshire) at the age of 28 d with an average body weight of 14.96 ± 0.32 kg were randomly divided into four treatments with eight replicates per treatment in a 2 × 2 factorial arrangement. Treatments included basal diet (IVE-PGO-), basal diet + 1,000 mg/kg PGO (IVE-PGO+), basal diet + 500 mg/kg IVE (IVE+PGO-), and basal diet + 500 mg/kg IVE + 1,000 mg/kg PGO (IVE+PGO+). All the piglets were housed individually for the 42-d trial period after 7-d adaptation. The piglets were euthanized at the end of the experiment and the liver and jejunum samples were taken and subjected to immunohistochemistry, Western blotting, as well as antioxidant and qRT-PCR analysis. Significant interactions were observed between IVE and PGO for total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) in serum (42 d), liver, and jejunum; malondialdehyde (MDA) in serum (21 d); and mRNA and protein expression of kelch sample related protein-1 (Keap1) and nuclear factor erythroid-2 related factor (Nrf2)/Keap1 in the liver and jejunum (P < 0.05). Both IVE and PGO improved (P < 0.05) T-SOD and GSH-Px in the serum (42 d), liver, and jejunum, and the mRNA and protein expression of Nrf2 and Nrf2/Keap1 in the liver and jejunum, but decreased (P < 0.05) MDA in the serum (21 d) and the mRNA and protein expression of Keap1 in the liver and jejunum. Immunohistochemical results confirmed that IVE and PGO enhanced the positive reactions of Nrf2 but weakened Keap1 in both the liver and jejunum. In conclusion, the results confirmed that IVE (500 mg/kg) and PGO (1,000 mg/kg) can improve the antioxidant capacity of weaned piglets and that the interaction effect between IVE and PGO is significant. At the same time, the fact that IVE and PGO activate the Nrf2/Keap1 in the liver and jejunum signaling pathway suggests that they play an important role in the ameliorative antioxidant capacity of weaned piglets. Therefore, the combination of IVE and PGO could be recommended as a new potential alternative to antibiotics in piglets' diets.

Effects of zearalenone-induced oxidative stress and Keap1-Nrf2 signaling pathway-related gene expression in the ileum and mesenteric lymph nodes of post-weaning gilts.

Zearalenone (ZEA) contamination of feed affects animal husbandry and the human health. Currently, the molecular mechanism underlying small intestine-related diseases caused by ZEA-induced oxidative stress is not well understood. In this study, we aimed to identify the mechanisms involved in ZEA (0.5-1.5 mg/kg)-induced oxidative stress in the ileum and mesenteric lymph nodes (MLNs) and the role of the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in post-weaning gilts. Forty post-weaning gilts (Landrace × Yorkshire × Duroc) with an average body weight of 14.01 ± 0.86 kg were randomly allocated to four groups and fed a corn-soybean meal basal diet supplemented with < 0.1, 0.5, 1.0, or 1.5 mg/kg ZEA. The results showed that the activity of total superoxide dismutase and glutathione peroxidase decreased (p < 0.05) linearly and quadratically and that the content of malondialdehyde increased (p < 0.05) quadratically in the ileum and MLNs with increasing ZEA in the diet. Immunohistochemical analysis showed that the expression of Nrf2 and glutathione peroxidase 1 (Gpx1) immunoreactive proteins in the ileum and MLNs were significantly enhanced with increasing ZEA. The relative mRNA and protein expression of Nrf2, Gpx1, quinone oxidoreductase 1 (Nqo1), hemeoxygenase 1 (Ho1), modifier subunit of glutamate-cysteine ligase (Gclm), and catalytic subunit of glutamate-cysteine ligase (Gclc) increased (p < 0.05) linearly and quadratically, and the relative mRNA and protein expression of Keap1 decreased (p < 0.05) linearly and quadratically in the ileum with increasing ZEA concentrations in the diet. Further, the relative mRNA and protein expression of Nrf2 and Gpx1 increased (p < 0.05) linearly and quadratically, and the relative mRNA and protein expression of Nqo1, Ho1, and Gclm decreased (p < 0.05) quadratically in the MLNs as ZEA concentrations increased in the diet. Our results provide valuable genetic information on ZEA-induced oxidative stress in the ileum and MLNs of post-weaning gilts and have elucidated the key regulatory genes involved in the Keap1-Nrf2 signaling pathway. Results indicated that the Keap1-Nrf2 signaling pathway might be a key target to further prevent and treat ZEA-induced injury to the ileum in post-weaning gilts.

Effect of Illicium verum or Eucommia ulmoides leaf extracts on the anti-stress ability, and mRNA and protein expression of Nrf2 and TNF-α in Duroc × Landrace × Yorkshire and Chinese native Licha-black nursery piglets.

Plant extracts are considered to be an effective alternative to antibiotics in response to weaning stress in piglets. This study evaluated the effect of Illicium verum extracts (IVE) or Eucommia ulmoides leaf extracts (ELE) on growth performance, serum and liver antioxidant ability of nursery piglets, as well as the difference of IVE and ELE on Duroc × Landrace × Yorkshire (DLY) and Chinese native Licha-black (LCB) piglets. A total of 96 nursery piglets (48 DLY and 48 LCB piglets) with an average body weight of 11.22 ± 0.32 kg were randomly divided into four treatments in a 2 × 4 factorial design. Each treatment had four replicates with 3 DLY and 3 LCB piglets per replicate respectively. Treatments included: basal diet, basal diet + 500 mg/kg IVE, basal diet + 250 mg/kg ELE and basal diet + 50 mg/kg chlortetracycline (CHL). All piglets were housed individually for the 42 days trial period after 7 days adaptation. Results showed that there were significant interactions (p < .05) between piglets species and dietary treatments in average daily gain (ADG) and feed efficiency, serum and hepatic glutathione peroxidase (GSH-Px) and malondialdehyde (MDA), hepatic integral optical density (IOD) of α-tumour necrosis factor (TNF-α), hepatic relative mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2)/TNF-α and protein expression of TNF-α. Regardless of piglets species, supplementation with IVE and ELE increased (p < .05) ADG and feed efficiency, T-SOD and GSH-Px in serum and liver, hepatic IOD of Nrf2, hepatic mRNA and protein expression of Nrf2/TNF-α. However, CHL treatment resulted in lower (p < .05) serum GSH-Px and hepatic mRNA and protein expression of Nrf2/TNF-α, and higher hepatic MDA and IOD of TNF-α. Compared to LCB, DLY piglets had higher (p < .05) ADG and feed efficiency, serum and hepatic MDA, and protein expression of TNF-α, but lower (p < .05) ADFI, liver index, serum and hepatic GSH-Px, hepatic IOD of TNF-α, mRNA expressions of Nrf2/TNF-α were observed. In conclusion, Illicium verum (500 mg/kg) and Eucommia ulmoides leaf (250 mg/kg) extracts can increase the growth performance and antioxidant ability of DLY and LCB piglets, while chlortetracycline produces undesirable side-effects on the antioxidant ability of DLY and LCB piglets. Illicium verum and Eucommia ulmoides leaf extracts produced different antioxidant effects in DLY and LCB piglets with the Chinese native Licha-black pig responding better than Duroc × Landrace × Yorkshire.