Natural feed contaminant zearalenone decreases the expressions of important pro- and anti-inflammatory mediators and mitogen-activated protein kinase/NF-κB signalling molecules in pigs

The potential effects of antioxidant feed additives in mitigating the adverse effects of corn naturally contaminated with Fusarium mycotoxins on antioxidant systems in the intestinal mucosa, plasma, and liver in weaned pigs

Seventy-two piglets (6.0 kg BW) were randomly distributed within six different dietary treatments to evaluate the effect of deoxynivalenol (DON) and the potential of four antioxidant feed additives in mitigating the adverse effects of DON on growth performances and oxidative status. Dietary treatments were as follows: control diet 0.8 mg/kg DON; contaminated diet (DON-contaminated diet) 3.1 mg/kg DON; and four contaminated diets, each supplemented with a different antioxidant feed additive, DON + vitamins, DON + organic selenium (Se)/glutathione (GSH), DON + quercetin, and DON + COMB (vitamins + Se/GSH + quercetin from the other treatments). Although DON was the main mycotoxin in the contaminated diet, this diet also contained 1.8 mg/kg of zearalenone (ZEN). The "mycotoxin" effects therefore included the combined effect of these two mycotoxins, DON, and ZEN. The DON-ZEN ingestion did not affect growth performances, average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F ratio), but partially induced oxidative stress in weaned pigs as shown by increased malondialdehyde (MDA) content in the plasma and superoxide dismutase (SOD) activity in liver (P < 0.05). However, no change in the activity of other antioxidant enzymes or GSH concentrations was observed in plasma and liver of piglets fed the DON-contaminated diet (P > 0.05). Supplementation with individual antioxidant feed additive had a limited effect in weaned pigs fed DON-ZEN-contaminated diets. Combination of antioxidants (vitamins A, C, and E, quercetin, and organic Se/GSH) reduced plasma and liver MDA content and SOD activity in liver (P < 0.05) of piglets fed DON-ZEN-contaminated diets. Furthermore, this combination also reduced MDA content in the ileum (P < 0.05), although activity of glutathione peroxidases (GPx), SOD or catalase (CAT) in the ileum was not affected by DON-ZEN contamination or antioxidant supplements. In conclusion, DON-ZEN contamination induced oxidative stress in weaned pigs and combination of antioxidant feed additives restored partially the oxidative status. Further studies will be necessary to assess whether the effects of antioxidant feed additives on oxidative status are specific when feed is contaminated with DON-ZEN.

Zearalenone mycotoxin affects immune mediators, MAPK signalling molecules, nuclear receptors and genome-wide gene expression in pig spleen

The toxicity of zearalenone (ZEA) was evaluated in swine spleen, a key organ for the innate and adaptative immune response. Weaned pigs were fed for 18 days with a control or a ZEA contaminated diet. The effect of ZEA was assessed on wide genome expression, pro- (TNF-α, IL-8, IL-6, IL-1β, IFN-γ) and anti-inflammatory (IL-10, IL-4) cytokines, other molecules involved in inflammatory processes (MMPs/TIMPs), as well as signaling molecules, (p38/JNK1/JNK2-MAPKs) and nuclear receptors (PPARγ/NFkB/AP-1/STAT3/c-JUN). Microarray analysis showed that 46% of total number of differentially expressed genes was involved in cellular signaling pathway, 13% in cytokine network and 10% in the inflammatory response. ZEA increased expression and synthesis of pro- inflammatory (TNF-α, IL-8, IL-6, IL-1β) and had no effect on IFN-γ, IL-4 and IL-10 cytokines in spleen. The inflammatory stimulation might be a consequence of JNK pathway activation rather than of p-38MAPK and NF-kB involvement whose gene and protein expression were suppressed by ZEA action. In summary, our findings indicated the role of ZEA as an immune disruptor at spleen level.

Induction of pro-inflammatory gene expression by Escherichia coli and mycotoxin zearalenone contamination and protection by a Lactobacillus mixture in porcine IPEC-1 cells

This work investigated the effect of Escherichia coli K88 and zearalenone contamination on pro-inflammatory gene expression (Toll like receptors, cytokines) and signalling molecules and the protective activity of a mixture of Lactobacilli sp. (Lactobacillus plantarum, Lactobacillus acidofilus and Lactobacillus paracasei) in porcine intestinal epithelial cells as part of the local immune system. IPEC-1 cell monolayer was exposed for 1 h to the individual or combined action of E. coli, zearalenone and lactobacilli mixture. Our results showed that TLRs (1-10) and cytokine (IL-1,-6,-8,-10, TNF-α, IFN-γ) genes expressed early (after 1 h of culture) in IPEC-1 cells. E. coli alone increased the TLRs mRNA expression, especially TLR4 and the inflammatory cytokines while ZEA alone showed either no effect or a marginally effect on TLRs, cytokines, and signalling genes when compared to untreated cells. The combined actions of the two contaminants lead to a synergistically up-regulation of key cytokines (IFN-γ, IL-10 and TNF-α) and TLRs (-2,-3,-4,-6, and -10). The live lactobacilli mixture was able to attenuate the pathogen and mycotoxin-induced response by downregulated the majority of inflammatory related genes suggesting that this mixture has an immunomodulatory potential and may be used to lower the inflammatory response.

Exposure to zearalenone mycotoxin alters in vitro porcine intestinal epithelial cells by differential gene expression

The gut represents the main route of intoxication with mycotoxins. To evaluate the effect and the underlying molecular changes that occurred when the intestine is exposed to zearalenone, a Fusarium sp mycotoxin, porcine epithelial cells (IPEC-1) were treated with 10μM of ZEA for 24h and analysed by microarray using Gene Spring GX v.11.5. Our results showed that 10μM of ZEA did not affect cell viability, but can increase the expression of toll like receptors (TLR1-10) and of certain cytokines involved in inflammation (TNF-α, IL-1β, IL-6, IL-8, MCP-1, IL-12p40, CCL20) or responsible for the recruitment of immune cells (IL-10, IL-18). Microarray results identified 190 genes significantly and differentially expressed, of which 70% were up-regulated. ZEA determined the over expression of ITGB5 gene, essential against the attachment and adhesion of ETEC to porcine jejunal cells and of TFF2 implicated in mucosal protection. An up-regulation of glutathione peroxidase enzymes (GPx6, GPx2, GPx1) was also observed. Upon ZEA challenge, genes like GTF3C4 responsible for the recruitment of polymerase III and initiation of tRNA transcription in eukaryotes and STAT5B were significantly higher induced. The up-regulation of CD97 gene and the down-regulation of tumour suppressor genes (DKK-1, PCDH11X and TC531386) demonstrates the carcinogenic potential of ZEA.

ω-3 PUFA rich camelina oil by-products improve the systemic metabolism and spleen cell functions in fattening pigs

Camelina oil-cakes results after the extraction of oil from Camelina sativa plant. In this study, camelina oil-cakes were fed to fattening pigs for 33 days and its effect on performance, plasma biochemical analytes, pro-/anti-inflammatory mediators and antioxidant detoxifying defence in spleen was investigated in comparison with sunflower meal. 24 crossbred TOPIG pigs were randomly assigned to one of two experimental dietary treatments containing either 12% sunflower meal (treatment 1-T1), or 12.0% camelina oil-cakes, rich in polyunsaturated fatty acids ω-3 (ω-3 PUFA) (treatment 2-T2). The results showed no effect of T2 diet (camelina cakes) on feed intake, average weight gain or feed efficiency. Consumption of camelina diet resulted in a significant decrease in plasma glucose concentration (18.47%) with a trend towards also a decrease of plasma cholesterol. In spleen, T2 diet modulated cellular immune response by decreasing the protein and gene expression of pro-inflammatory markers, interleukin 1-beta (IL-1β), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and interleukin (IL-8) and cyclooxigenase 2 (COX-2) in comparison with T1 diet. By contrast, T2 diet increased (P<0.05) in spleen the mRNA expression of antioxidant enzymes, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase 1 (GPx1) by 3.43, 2.47 and 1.83 fold change respectively, inducible nitric oxide synthase (iNOS) (4.60 fold), endothelial nitric oxide synthase (eNOS) (3.23 fold) and the total antioxidant level (9.02%) in plasma. Camelina diet increased also peroxisome-proliferator activated receptor gamma (PPAR-γ) mRNA and decreased that of mitogen-activated protein kinase 14 (p38α MAPK) and nuclear factor of kappa light polypeptide gene enhancer in B-cells (NF-κB). At this level of inclusion (12%) camelina oil-cakes appears to be a potentially alternative feed source for pig which preserves a high content of ω-3 PUFA indicating antioxidant properties by the stimulation of detoxifying enzymes expression and the suppression of spleen pro-inflammatory markers.

Diminution of hepatic response to 7, 12-dimethylbenz(α)anthracene by ethyl acetate fraction of Acacia catechu willd. through modulation of xenobiotic and anti-oxidative enzymes in rats

BACKGROUND

Liver is the primary metabolizing site of body and is prone to damage by exogenous as well as endogenous intoxicants. Polycyclic aromatic hydrocarbons such as 7, 12- dimethylbenz(α)anthracene (DMBA) is an exogenous hepatotoxin, which is well known for modulating phase I, II and anti-oxidative enzymes of liver. Plants contain plethora of polyphenolic compounds which can reverse the damaging effect of various xenobiotics. The present study investigated protective role of the ethyl acetate fraction of Acacia catechu Willd. (EAF) against DMBA induced alteration in hepatic metabolizing and anti-oxidative enzymes in rats.

METHODOLOGY AND PRINCIPAL FINDINGS

The rats were subjected to hepatic damage by treating with DMBA for 7 weeks on alternative days and treatment schedule was terminated at the end of 14 weeks. The rats were euthanized at the end of protocol and livers were homogenized. The liver homogenates were used to analyse phase I (NADPH-cytochrome P450 reducatse, NADH-cytochrome b5 reductase, cytochrome P420, cytochrome b5), phase II (glutathione-S-transferase, DT diaphorase and γ-Glutamyl transpeptidase) and antioxidative enzymes (catalase, superoxide dismutase, ascorbate peroxidase, glutathione reductase, guiacol peroxidase and lactate dehydrogenase). Furthermore, other oxidative stress parameters (thiobarbituric acid reactive substances, lipid hydroperoxides and conjugated dienes and reduced glutathione) and liver marker enzymes (serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase and alkaline phosphatase) were also studied. The DMBA induced significant changes in activity of hepatic enzymes that was reversed by treatment with three dose levels of EAF.

CONCLUSION

It is concluded that EAF affords hepato-protection against DMBA in rats through modulation of phase I, II and anti-oxidative enzymes.