Resveratrol alleviates oxidative stress induced by oxidized soybean oil and improves gut function via changing gut microbiota in weaned piglets

Abstract

Background: Oxidized soybean oil (OSO) has been shown to impair growth and exacerbate inflammation, leading to intestinal barrier injury in animals. Recent evidence suggests important roles for resveratrol (RES) in the promoting growth performance, antioxidant capacity, anti-inflammatory, and regulate intestinal barriers in animals. Therefore, The objectives of this study are to investigate the effects of dietary RES (purity 98%) supplementation on the growth performance, antioxidant capacity, inflammatory state, and intestinal function of weaned piglets challenged with OSO.

Methods: A total of 28 castrated weaned male piglets with a similar body weight of 10.19 ± 0.10 kg were randomly assigned to 4 dietary treatments for 28-d feeding trial with 7 replications per treatment and 1 piglet per replicate. Treatments were arranged as a 2 × 2 factorial with oil type [3% fresh soybean oil (FSO) vs. 3% OSO] and dietary RES (0 vs. 300 mg/kg).

Results: The results showed that relative to the FSO group, OSO stress tended to decrease the average daily feed intake (ADFI), and decreased the activity levels of lipase, villus/crypt ratio (VCR), the mRNA expression of FABP1, SOD2, IL-10 and ZO-1 in the jejunum, and SOD2, GPX1, occludin and ZO-1 in the colon, the levels of acetic acid in the colonic digesta, whereas up-regulated the mRNA expression of IL-1β and TNF-α in the jejunum (P < 0.05). Moreover, dietary supplementation with RES increased ether extract (EE), the activity levels of sucrase, lipase, α-amylase, villus height (VH) and VCR, the mRNA expression of FABP1, SOD2, IL-10 and occludin in the jejunum, and FABP1, PPAR-γ, GPX1, occludin and ZO-1 in the colon, and the abundance of Firmicutes, acetic and propionic acid, but decreased the levels of D-lactic acid in the plasma, the abundance of Bacteroidetes in the colonic digesta of weaned piglets compared to the non-RES group (P < 0.05). Meanwhile, in the interaction effect analysis, relative to the OSO group, dietary RES supplementation in the diets supplemented with OSO increased the activity levels of trypsin, VH in the jejunum, the abundance of Actinobacteria, the levels of butyric acid of weaned piglets, but failed to influence the activity levels of trypsin and VH, Actinobacteria abundance, the levels of butyric acid when diets were supplemented with FSO (interaction, P < 0.05). Relative to the OSO group, dietary RES supplementation in the diets supplemented with OSO decreased the activity levels of DAO in the plasma of weaned piglets but failed to influence the activity levels of DAO when diets were supplemented with FSO (interaction, P < 0.05). Relative to the FSO group, dietary RES supplementation in the diets supplemented with FSO decreased the level of propionic acid, whereas RES supplementation failed to influence the level of propionic acid when the diet was supplemented with OSO (interaction, P < 0.01).

Conclusions: Inclusion of OSO intensified inflammatory states and impaired the intestinal health characteristics of weaned piglets. Dietary RES supplementation improved the antioxidant capacity, anti-inflammatory activity, and intestinal morphology. Further studies showed that the protective effects of RES on gut health could be linked to the decreased abundance of Prevotella_1, Clostridium_sensu_stricto_6, and Prevotellaceae_UCG003 and increased levels of acetic and propionic acid.

Keywords: Inflammation; Intestinal barrier; Intestinal health; Oxidative stress; Oxidized soybean oil; Piglets; Resveratrol.

Fig. 1

Effect of RES supplementation on activities of the jejunum digestive enzymes and mRNA expression of the jejunum and the colon fat transporter genes in OSO-challenged weaned piglets. A Digestive enzymes activity in the jejunum. B The mRNA expression of fat transporter genes in the jejunum and colon. The column and its bar represent the mean value and standard error (n = 7 piglets/group), respectively; labeled means in a row without a common letter differ, P ≤ 0.05; Note: FSO, fresh soybean oils; FSO + RES, fresh soybean oils with resveratrol; OSO, oxidized soybean oil; OSO + RES, oxidized soybean oil with resveratrol

Fig. 2

Effect of RES supplementation on the mRNA expression of jejunm, colon oxidative stress genes, inflammatory factors of the jejunum and colon in OSO-challenged weaned piglets. A The mRNA expression of oxidative stress genes in the jejunum and colon; B The mRNA expression of inflammatory factors of the colon; C The mRNA expression of inflammatory factors of the jejunum. The column and its bar represent the mean value and standard error (n = 7 piglets/group), respectively; labeled means in a row without a common letter differ, P ≤ 0.05; Note: FSO, fresh soybean oils; FSO + RES, fresh soybean oils with resveratrol; OSO, oxidized soybean oil; OSO + RES, oxidized soybean oils with resveratrol

Fig. 3

Effect of RES supplementation on intestinal morphology in OSO-challenged weaned piglets FSO, fresh soybean oil; FSO + RES, fresh soybean oils with resveratrol; OSO, oxidized soybean oil; OSO + RES, oxidized soybean oil with resveratrol. Note: Original magnification 200 × , scale bar 200 μm

Fig. 4

ZO-1, Occludin, Ki-67 staining on immunofluorescence images in paraformaldehyde-fixed cross-sections from the jejunum and the colon of weaned piglets. FSO, fresh soybean oil; FSO + RES, fresh soybean oil with resveratrol; OSO, oxidized soybean oil; OSO + RES, oxidized soybean oils with resveratrol. Note: 100 × and 400 × magnification, scale bar, 200 μm

Fig. 5

Effect of RES supplementation on immunofluorescence images of the jejunum, colon ZO-1, Occludin, Ki-67 and mRNA expression of the jejunum and colon ZO-1, Occludin, Claodin-5, Claodin-6 genes in OSO-challenged weaned piglets. A The mRNA expression of ZO-1, Occludin, Claodin-5, Claodin-6 in the jejunum; B The mRNA expression of ZO-1, Occludin, Claodin-5, Claodin-6 in the colon; C ZO-1, Occludin, Ki-67 staining on immunofluorescence images in the jejunum and colon; The column and its bar represent the mean value and standard error (n = 3 piglets/group), respectively; labeled means in a row without a common letter differ, P ≤ 0.05; Note: FSO, fresh soybean oil; FSO + RES, fresh soybean oil with resveratrol; OSO, oxidized soybean oil; OSO + RES, oxidized soybean oil with resveratrol

Fig. 6

Effect of RES supplementation on the phylum and genus of the colon digesta microbiota in OSO-challenged weaned piglets. A At the phylum; B The abundance of intestinal flora at phyum level; C At the genus; D The abundance of intestinal flora at genus level. The column and its bar represent the mean value and standard error (n = 7 piglets/group), respectively; labeled means in a row without a common letter differ, P ≤ 0.05; Note: FSO, fresh soybean oil; FSO + RES, fresh soybean oil with resveratrol; OSO, oxidized soybean oil; OSO + RES, oxidized soybean oil with resveratrol

Fig. 7

Effect of RES supplementation on levels of the colonic digesta SCFAs and mRNA expression of colon GPR41, GPR43 in OSO-challenged weaned piglets. A The levels of SCFAs in colon digesta; B The mRNA expression of GPR41, GPR43 in colon. The column and its bar represent the mean value and standard error (n = 7 piglets/group), respectively; labeled means in a row without a common letter differ, P ≤ 0.05; Note: FSO, fresh soybean oil; FSO + RES, fresh soybean oil with resveratrol; OSO, oxidized soybean oil; OSO + RES, oxidized soybean oil with resveratrol

Fig. 8

RDA analyses based on the identified differential genera of RES and OSO revealed significantly altered apparent digestibility, proinflammatory factor, and intestinal enzymatic activity-related indices. Note: FSO, fresh soybean oil; FSO + RES, fresh soybean oil with resveratrol; OSO, oxidized soybean oil; OSO + RES, oxidized soybean oil with resveratrol. For the relationship between groups and the identified altered phenotypes, if the plot projection of one sample occurred in the positive direction of the extending line of the identified altered phenotypes, then the treatment of this sample could promote this phenotypic change