The Effects of Deoxynivalenol and Zearalenone on the Pig Large Intestine. A Light and Electron Microscopy Study

MicroRNAs: exploring their role in farm animal disease and mycotoxin challenges

MicroRNAs (miRNAs) serve as key regulators in gene expression and play a crucial role in immune responses, holding a significant promise for diagnosing and managing diseases in farm animals. This review article summarizes current research on the role of miRNAs in various farm animal diseases and mycotoxicosis, highlighting their potential as biomarkers and using them for mitigation strategies. Through an extensive literature review, we focused on the impact of miRNAs in the pathogenesis of several farm animal diseases, including viral and bacterial infections and mycotoxicosis. They regulate gene expression by inducing mRNA deadenylation, decay, or translational inhibition, significantly impacting cellular processes and protein synthesis. The research revealed specific miRNAs associated with the diseases; for instance, gga-miR-M4 is crucial in Marek's disease, and gga-miR-375 tumor-suppressing function in Avian Leukosis. In swine disease such as Porcine Respiratory and Reproductive Syndrome (PRRS) and swine influenza, miRNAs like miR-155 and miR-21-3p emerged as key regulatory factors. Additionally, our review highlighted the interaction between miRNAs and mycotoxins, suggesting miRNAs can be used as a biomarker for mycotoxin exposure. For example, alterations in miRNA expression, such as the dysregulation observed in response to Aflatoxin B1 (AFB1) in chickens, may indicate potential mechanisms for toxin-induced changes in lipid metabolism leading to liver damage. Our findings highlight miRNAs potential for early disease detection and intervention in farm animal disease management, potentially reducing significant economic losses in agriculture. With only a fraction of miRNAs functionally characterized in farm animals, this review underlines more focused research on specific miRNAs altered in distinct diseases, using advanced technologies like CRISPR-Cas9 screening, single-cell sequencing, and integrated multi-omics approaches. Identifying specific miRNA targets offers a novel pathway for early disease detection and the development of mitigation strategies against mycotoxin exposure in farm animals.

Toxicodynamic of combined mycotoxins: MicroRNAs and acute-phase proteins as diagnostic biomarkers

Mycotoxins, ubiquitous contaminants in food, present a global threat to human health and well-being. Mitigation efforts, such as the implementation of sound agricultural practices, thorough food processing, and the advancement of mycotoxin control technologies, have been instrumental in reducing mycotoxin exposure and associated toxicity. To comprehensively assess mycotoxins and their toxicodynamic implications, the deployment of effective and predictive strategies is imperative. Understanding the manner of action, transformation, and cumulative toxic effects of mycotoxins, moreover, their interactions with food matrices can be gleaned through gene expression and transcriptome analyses at cellular and molecular levels. MicroRNAs (miRNAs) govern the expression of target genes and enzymes that play pivotal roles in physiological, pathological, and toxicological responses, whereas acute phase proteins (APPs) exert regulatory control over the metabolism of therapeutic agents, both endogenously and posttranscriptionally. Consequently, this review aims to consolidate current knowledge concerning the regulatory role of miRNAs in the initiation of toxicological pathways by mycotoxins and explores the potential of APPs as biomarkers following mycotoxin exposure. The findings of this research highlight the potential utility of miRNAs and APPs as indicators for the detection and management of mycotoxins in food through biological processes. These markers offer promising avenues for enhancing the safety and quality of food products.

Toxicity, biodegradation, and nutritional intervention mechanism of zearalenone

Zearalenone (ZEA), a global mycotoxin commonly found in a variety of grain products and animal feed, causes damage to the gastrointestinal tract, immune organs, liver and reproductive system. Many treatments, including physical, chemical and biological methods, have been reported for the degradation of ZEA. Each degradation method has different degradation efficacies and distinct mechanisms. In this article, the global pollution status, hazard and toxicity of ZEA are summarized. We also review the biological detoxification methods and nutritional regulation strategies for alleviating the toxicity of ZEA. Moreover, we discuss the molecular detoxification mechanism of ZEA to help explore more efficient detoxification methods to better reduce the global pollution and hazard of ZEA.

A Cohort Study Investigating Zearalenone Concentrations and Selected Steroid Levels in Patients with Sigmoid Colorectal Cancer or Colorectal Cancer

THE AIM

In this study was to determine if sigmoid colorectal cancer (SCC) and colorectal cancer (CRC) in women (W) and men (M) is accompanied by zearalenone (ZEN) mycotoxicosis and changes in selected steroid levels.

MATERIALS AND METHODS

This cohort study was conducted on female and male patients selected from a population based on the presence of SCC or CRC, which was accompanied by the presence or absence (control group) of ZEN in their blood. The control group consisted of 17 patients with symptoms of SCC and CRC, where ZEN and its metabolites were not detected in the peripheral blood. The experimental groups comprised a total of 16 patients with SCC and CRC, where ZEN, but not its metabolites, was detected in their peripheral blood samples.

RESULTS

In groups SCC and CRC, the ZEN levels were very high, in the range from 214 to 289 ng/mL of blood. Considerable variations were observed in the concentrations of steroid hormones. Estradiol (E2) levels ranged from 166.25 (group C) to 325 pg/mL (group CRC) in women and from 98 (group C) to 95.5 pg/mL (group CRC) in men. Progesterone (P4) levels ranged from 12.09 (group C) to 13.64 ng/mL (group SCC) in women and from 6.98 (group CRC) to 12.01 ng/mL (group C) in men.

CONCLUSIONS

These results indicate that post-menopausal women and similarly aged elderly men have a high and individualized demand for estrogen that is relatively effectively met by ZEN, which triggers qualitative changes in estrogen receptors. The shortage of ZEN metabolites (values under the sensitivity of the method) confirmed the high estrogen demand in the studied subjects. The presence or absence of ZEN could have influenced the therapeutic outcomes in the analyzed patients.

Quercetin Attenuates the Combined Effects of Zearalenone and Lipopolysaccharide on IPEC-J2 Cell Injury through Activating the Nrf2 Signaling Pathway

Zearalenone (ZEA) is a mycotoxin with an estrogen-like effect that is widely found in feed. Lipopolysaccharides (LPS) derived from Gram-negative bacteria are a common endotoxin, and both toxins have effects on human and livestock health. During animal feeding, ZEA as an exotoxin and LPS as an endotoxin have the potential to co-exist in organisms. At present, other studies have only focused on the hazards of single toxins, but there are fewer studies on the coexistence and interaction between ZEA and LPS. Therefore, a further study to investigate the combined toxic effects of different concentrations of ZEA and LPS is warranted. Quercetin (QUE) is a natural flavonoid compound with strong antioxidant and anti-inflammatory properties. It is unclear whether QUE can mitigate the combined effects of ZEA and LPS. IPEC-J2, isolated from the jejunum of non-breastfed neonatal piglets, is an ideal model for the study of epithelial cell transport, intestinal bacterial interactions, and the nutrient modulation of intestinal function. Therefore, the purpose of the present study was to demonstrate the effect of QUE in alleviating the combined toxic effect of ZEA and LPS on IPEC-J2 cell damage. Cell viability was measured after treating IPEC-J2 cells sequentially with 10, 20, 30, 40, 60, 80, and 100 μM ZEA, 1, 10, 50, and 100 μg/mL LPS, and 20, 40, 60, 80, 100, and 200 μM QUE for 24 h. Based on the cell viability results, 20 μM ZEA and 1 μg/mL LPS were selected as the most suitable concentrations for further analysis. For QUE, 20 μM increased the cell viability, while 40-200 μM QUE decreased the cell viability. Therefore, for the subsequent study, 20 μM QUE was selected in combination with 20 μM ZEA and 1 μg/mL LPS. The results showed that QUE increased the cellular viability and decreased the LDH content more compared to the effects of the ZEA+LPS group. At the gene level, QUE addition up-regulated the expression of Nrf2, HO-1, SOD2, and NQO1 at the gene or protein level compared to those of the ZEA+LPS group. The measurement of tight junction-related genes and proteins showed QUE up-regulated the expression of Claudin, ZO-1, and Occludin genes and proteins more than in the ZEA+LPS group. QUE addition reduced the rate of apoptosis more than that in the ZEA+LPS group. The expressions of Bcl-2 and Bax were examined at the gene level, and QUE addition significantly reduced the Bax gene expression level compared to that of the ZEA+LPS group, but there was no apparent variation in the expression level of Bcl-2. In summary, QUE can alleviate the combined toxic effects of ZEA and LPS on IPEC-J2 cells via modulating the Nrf2 signaling pathway, up-regulating the expression of antioxidative genes, and enhancing the intestinal barrier.

Immunohistochemical Expression (IE) of Oestrogen Receptors in the Intestines of Prepubertal Gilts Exposed to Zearalenone

This study was conducted to determine if a low monotonic dose of zearalenone (ZEN) affects the immunohistochemical expression (IE) of oestrogen receptor alpha (ERα) and oestrogen receptor beta (ERβ) in the intestines of sexually immature gilts. Group C (control group; n = 18) gilts were given a placebo. Group E (experimental group; n = 18) gilts were dosed orally with 40 μg ZEN /kg body weight (BW), each day before morning feeding. Samples of intestinal tissue were collected post-mortem six times. The samples were stained to analyse the IE of ERα and Erβ in the scanned slides. The strongest response was observed in ERα in the duodenum (90.387-average % of cells with ERα expression) and in ERβ in the descending colon (84.329-average % of cells with ERβ expression); the opposite response was recorded in the caecum (2.484-average % of cells with ERα expression) and the ascending colon (2.448-average % of cells with ERα expression); on the first two dates of exposure, the digestive tract had to adapt to ZEN in feed. The results of this study, supported by a mechanistic interpretation of previous research findings, suggest that ZEN performs numerous functions in the digestive tract.

Chronic exposure to zearalenone induces intestinal inflammation and oxidative injury in adult Drosophila melanogaster midgut

In the past decade, mycotoxin zearalenone (ZEN)-induced gastrointestinal adverse effects have been increasingly attracting worldwide attention. This study aimed to determine the gastrointestinal adverse effects of ZEN in Drosophila melanogaster (D. melanogaster) and reveal possible mechanisms of action of ZEN in insects. Here, chronic exposure of D. melanogaster to ZEN killed flies in a dose-dependent manner (2-20 µM). ZEN (20 µM) decreased the survival rates and climbing ability of flies, and activated immune deficiency-mediated intestinal immunity in midgut, leading to the production of antimicrobial peptides. Meanwhile, ZEN exposure induced morphological alteration of adult midgut. Further study suggested that high levels of oxidative stress was observed in ZEN-treated midgut due to the imbalance between the production of reactive oxygen species and the expression and activities of cellular antioxidant enzyme, including superoxide dismutase and catalase. ZEN-induced oxidative stress then caused cell death, impaired gut barrier function and increased gut permeability, leading to oxidative injury in midgut. Subsequently, ZEN-induce midgut injury further disrupted intestinal stem cell (ISC) homeostasis, stimulating ISC proliferation and tissue regeneration, but did not alter cell fate specification of ISC. Additionally, activation of Jun N-terminal kinase pathway was involved in ZEN-induced oxidative injury and tissue regeneration in midgut. Antioxidant vitamin E alleviated ZEN-induced oxidative injury to midgut epithelium. Collectively, this study provided additional evidences for ZEN-induced gastrointestinal adverse effects from an invertebrate model, extended our understanding of the mechanisms mediating mycotoxin toxicity in organisms.

Mycotoxin contamination in feeds and feed materials in China in year 2020

A survey of mycotoxin contamination in feed commodities in China was performed and the regional differences of mycotoxin contamination in new season corn was assessed during January 2020-November 2020 in this research. 1,610 samples were analyzed for the major mycotoxins, namely aflatoxins, zearalenone (ZEN), trichothecenes type B, fumonisins (FUM), fusariotoxin T-2 (T-2) and ochratoxin A (OTA) using methods of liquid chromatography-tandem mass spectrometry and enzyme linked immunosorbent assay. Generally, aflatoxins occurred in 16% of all samples, and ZEN, trichothecenes type B and FUM were more prevalent with positive rates of 47, 72, and 63%, respectively. T2 and OTA were rarely detected. In new season corn, samples were also seriously contaminated with ZEN, trichothecenes type B, and FUM at positive rates of 47, 76, and 79%, respectively, and their averages of positives were 112, 735, and 3,811 μg/kg, respectively. The patterns of mycotoxin occurrence showed distinct regional trends in new season corn samples. Samples from Shandong province were highly contaminated with FUM, while special attention should be paid to aflatoxins in Anhui and Jiangsu provinces of East China. The contents of trichothecenes type B and ZEN from northern to southern provinces showed downward trends. In new season corm, co-occurrence of mycotoxins was widespread, and combinations of ZEN, trichothecenes type B, and FUM were frequently observed in this study. Trichothecenes type B and ZEN concentrations showed a positive correlation coefficient of 0.294, suggesting that toxicological interactions of these toxins deserve attention.

Deoxynivalenol Induces Apoptosis via FOXO3a-Signaling Pathway in Small-Intestinal Cells in Pig

Deoxynivalenol (DON) is a mycotoxin that is found in feed ingredients derived from grains such as corn and wheat. Consumption of DON-contaminated feed has been shown to cause damage to the intestine, kidneys, and liver. However, the molecular mechanism by which DON exerts its effect in the small intestine is not completely understood. As a result, we profiled gene expression in intestinal epithelial cells treated with DON and examined the molecular function in vitro. We hypothesized that DON could induce apoptosis via the FOXO3a-signaling pathway in intestinal epithelial cells based on these findings. DON induced the apoptosis and the translocation of FOXO3a into the nucleus. Moreover, the inhibiting of FOXO3a alleviated the apoptosis and expression of apoptosis-related genes (TRAL, BCL-6, CASP8, and CASP3). ERK1/2 inhibitor treatment suppressed the translocation of FOXO3a into the nucleus. Our discovery suggests that DON induces apoptosis in intestinal epithelial cells through the FOXO3a-signaling pathway.

Mycotoxin Contamination of Feeds and Raw Materials in China in Year 2021

In this research, we performed a large-scale survey of mycotoxin contamination in several feed commodities and assessed regional differences in mycotoxin occurrence in maize across China in 2021. Concentrations of aflatoxins, zearalenone (ZEN), fumonisins, and trichothecenes type B were analyzed in 2,643 raw material and compound feed samples collected from eight provinces. Generally, trichothecenes type B, fumonisins, and ZEN were most prevalent and detected in averages of positive concentrations at 1,167, 1,623, and 204 μg/kg, respectively. In the new season maize, samples were also seriously infested with trichothecenes type B, fumonisins, and ZEN, and their averages of positive concentrations were 1,302, 2,518, and 225 μg/kg, respectively. Wheat was commonly contaminated with trichothecenes type B and ZEN, and the highest concentration levels of trichothecenes type B, fumonisins, and ZEN were all detected in the samples from maize by-products. Among the different geographical regions, distinct trends were observed in new season maize. Samples from Shandong province were highly contaminated with trichothecenes type B, fumonisins, and ZEN, while special attention should be paid to aflatoxins and fumonisins in Anhui and Jiangsu provinces in East China. In addition, the present survey showed that compound feeds and raw materials are commonly contaminated by multiple mycotoxins. Trichothecenes type B and ZEN concentrations were correlated significantly in this survey.

Deoxynivalenol aggravates the immunosuppression in piglets and PAMs under the condition of PEDV infection through inhibiting TLR4/NLRP3 signaling pathway

Mycotoxins are toxic metabolites produced by fungi, which are ubiquitous in cereals and feed worldwide and threaten human and animal health. Deoxynivalenol (DON) is one of the most prevalent mycotoxins and causes a series of toxicities, especially enterotoxicity and immunotoxicity. Porcine epidemic diarrhea virus (PEDV) is a destructive enteropathogenic animal coronavirus, is often accompanied with DON contamination in the swine herd. Previous studies have shown that PEDV infection leads severe immunosuppression in pigs. However, whether DON exposure aggravates the PEDV-induced immunosuppression remains unclear. In this study, weaned piglet and porcine alveolar macrophage cell (PAM) models were established to explore the effects of DON on the PEDV-induced immunosuppression and to clarify its underlying mechanism. The in vivo results showed that 2.25 mg/kg feed DON significantly exacerbated the immunosuppressive effects on the PEDV-infected piglets, as demonstrated by the decreases in growth performance, the numbers of goblet cells and CD3⁺T cells, as well as the protein expressions of ZO-1, Claudin1 and Muc2, in addition to the increases in anti-inflammatory factors levels and the intestinal injury. Similarly, the in vitro results demonstrated that 3-4 μM DON markedly aggravated apoptosis, enhanced the expressions of anti-inflammatory factors, but reduced the migration and phagocytosis abilities of the PEDV-infected PAMs. Furthermore, DON significantly suppressed the expressions of TLR4/NLRP3 in vivo and in vitro. To contrast, lipopolysaccharide (LPS), the corresponding activator, obviously alleviated the DON-exacerbated immunosuppression. Our findings suggest that DON could aggravate host immunosuppression under the condition of PEDV infection through inhibiting TLR4/NLRP3 signaling pathway, and provide novel theoretical insights into the further studies on the immunotoxicity of DON contamination and PEDV-induced immunosuppression.

Zearalenone Exposure Triggered Cecal Physical Barrier Injury through the TGF-β1/Smads Signaling Pathway in Weaned Piglets

This study aims to investigate the effects of exposure to different dosages of zearalenone (ZEA) on cecal physical barrier functions and its mechanisms based on the TGF-β1/Smads signaling pathway in weaned piglets. Thirty-two weaned piglets were allotted to four groups and fed a basal diet supplemented with ZEA at 0, 0.15, 1.5, and 3.0 mg/kg, respectively. The results showed that 1.5 and 3.0 mg/kg ZEA damaged cecum morphology and microvilli, and changed distribution and shape of M cells. Moreover, 1.5 and 3.0 mg/kg ZEA decreased numbers of goblet cells, the expressions of TFF3 and tight junction proteins, and inhibited the TGF-β1/Smads signaling pathway. Interestingly, the 0.15 mg/kg ZEA had no significant effect on cecal physical barrier functions but decreased the expressions of Smad3, p-Smad3 and Smad7. Our study suggests that high-dose ZEA exposure impairs cecal physical barrier functions through inhibiting the TGF-β1/Smads signaling pathway, but low-dose ZEA had no significant effect on cecum morphology and integrity through inhibiting the expression of smad7. These findings provide a scientific basis for helping people explore how to reduce the toxicity of ZEA in feeds.

Zearalenone Affect the Intestinal Villi Associated with the Distribution and the Expression of Ghrelin and Proliferating Cell Nuclear Antigen in Weaned Gilts

This study explored and investigated how zearalenone (ZEA) affects the morphology of small intestine and the distribution and expression of ghrelin and proliferating cell nuclear antigen (PCNA) in the small intestine of weaned gilts. A total of 20 weaned gilts (42-day-old, D × L × Y, weighing 12.84 ± 0.26 kg) were divided into the control and ZEA groups (ZEA at 1.04 mg/kg in diet) in a 35-d study. Histological observations of the small intestines revealed that villus injuries of the duodenum, jejunum and ileum, such as atrophy, retardation and branching dysfunction, were observed in the ZEA treatment. The villi branch of the ileum in the ZEA group was obviously decreased compared to that of the ileum, jejunum and duodenum, and the number of lymphoid nodules of the ileum was increased. Additionally, the effect of ZEA (1.04 mg/kg) was decreased by the immunoreactivity and distribution of ghrelin and PCNA in the duodenal and jejunal mucosal epithelial cells. Interestingly, ZEA increased the immunoreactivity of ghrelin in the ileal mucosal epithelial cells and decreased the immunoreactivity expression of PCNA in the gland epithelium of the small intestine. In conclusion, ZEA (1.04 mg/kg) had adverse effects on the development and the absorptive capacity of the villi of the intestines; yet, the small intestine could resist or ameliorate the adverse effects of ZEA by changing the autocrine of ghrelin in intestinal epithelial cells.

Deoxynivalenol: Mechanisms of action and its effects on various terrestrial and aquatic species

Deoxynivalenol, a type B trichothecene mycotoxin produced by Fusarium species of fungi, is a ubiquitious contaminant of cereal grains worldwide. Chronic, low dose consumption of feeds contaminated with DON is associated with a wide range of symptoms in terrestrial and aquatic species including decreased feed intake and feed refusal, reduced weight gain, and altered nutritional efficiency. Acute, high dose exposure to DON may be associated with more severe symptoms such as vomiting, diarrhea, intestinal inflammation and gastrointestinal hemorrhage. The toxicity of DON is partly related to its ability to disrupt eukaryotic protein synthesis via binding to the peptidyl transferase site of the ribosome. Moreover, DON exerts its effects at the cellular level by activating mitogen activated protein kinases (MAPK) through a process known as the ribotoxic stress response (RSR). The outcome of DON-associated MAPK activation is dose and duration dependent; acute low dose exposure results in immunostimulation characterized by the upregulation of cytokines, chemokines and other proinflammatory-related proteins, whereas longer term exposure to higher doses generally results in apoptosis, cell cycle arrest, and immunosuppression. The order of decreasing sensitivity to DON is considered to be: swine > rats > mice > poultry ≈ ruminants. However, studies conducted within the past 10 years have demonstrated that some species of fish, such as rainbow trout, are highly sensitive to DON. The aims of this review are to explore the effects of DON on terrestrial and aquatic species as well as its mechanisms of action, metabolism, and interaction with other Fusarium mycotoxins. Notably, a considerable emphasis is placed on reviewing the effects of DON on different species of fish.

The Effect of 42-Day Exposure to a Low Deoxynivalenol Dose on the Immunohistochemical Expression of Intestinal ERs and the Activation of CYP1A1 and GSTP1 Genes in the Large Intestine of Pre-pubertal Gilts

Deoxynivalenol (DON) is a mycotoxin that contaminates various plant materials. Exposure to DON can disrupt hormonal homeostasis, decrease body weight gains and modulate the immune system in pigs. It can also cause diarrhea, vomiting, leukocytosis, hemorrhaging or even death. Prolonged exposure to low doses of DON can have serious health implications in mammals. This is the first in vivo study to show that per os administration of low DON doses probably contributes to specific dysfunctions in steroidogenesis processes by inducing the immunohistochemical expression of estrogen receptors alpha (ERα) in the entire gastrointestinal tract in strongly stained cells (3 points) and estrogen receptors beta (ERβ), but only in both investigated segments of the duodenum in pre-pubertal gilts. Therefore, the aim of this study was to determine whether a NOAEL dose of DON (12 μg DON/kg BW) administered per os over a period of 42 days induces changes in the immunohistochemical expression of ER in different intestinal segments and the transcriptional activation of CYP1A1 and GSTP1 genes in the large intestine of pre-pubertal gilts. This is the first report to demonstrate the expression of ER, in particular ERβ, with the associated consequences. The expression of ER was accompanied by considerable variations in the activation of CYP1A1 and GSTP1 genes, but it supported the maintenance of a stable consensus between the degree of mycotoxin exposure and the detoxifying effect in pre-pubertal gilts.

Zearalenone regulates key factors of the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1-nuclear factor erythroid 2-related factor 2 signaling pathway in duodenum of post-weaning gilts

OBJECTIVE

This study explored the mechanism 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 under conditions of zearalenone (ZEA)-induced oxidative stress in the duodenum of post-weaning gilts.

METHODS

Forty post-weaning gilts were randomly allocated to four groups and fed diets supplemented with 0, 0.5, 1.0, or 1.5 mg/kg ZEA.

RESULTS

The results showed significant reductions in the activity of the antioxidant enzymes total superoxide dismutase and glutathione peroxidase and increases the malondialdehyde content with increasing concentrations of dietary ZEA. Immunohistochemical analysis supported these findings by showing a significantly increased expression of Nrf2 and glutathione peroxidase 1 (GPX1) with increasing concentrations of ZEA. The relative mRNA and protein expression of Nrf2, GPX1 increased linearly (p<0.05) and quadratically (p<0.05), which was consistent with the immunohistochemical results. The relative mRNA expression of Keap1 decreased linearly (p<0.05) and quadratically (p<0.05) in the duodenum as the ZEA concentration increased in the diet. The relative mRNA expression of modifier subunit of glutamate-cysteine ligase (GCLM) increased quadratically (p<0.05) in all ZEA treatment groups and the relative mRNA expression of quinone oxidoreductase 1 (NQO1) catalytic subunit of glutamate-cysteine ligase decreased linearly (p<0.05) and quadratically (p<0.05) in the ZEA1.0 group and ZEA1.5 group. The relative protein expression of Keap1 and GCLM decreased quadratically (p<0.05) in the duodenum as the ZEA concentration increased in the diet, respectively. The relative protein expression of NQO1 increased linearly (p<0.05) and quadratically (p<0.05) in all ZEA treatment groups in the duodenum.

CONCLUSION

These findings suggest that ZEA regulates the expression of key factors of the Keap1-Nrf2 signaling pathway in the duodenum, which enables resistance to ZEA-induced oxidative stress. Further studies are needed to examine the effects of ZEA induced oxidative stress on other tissues and organs in post-weaning gilts.

Low doses of individual and combined deoxynivalenol and zearalenone in naturally moldy diets impair intestinal functions via inducing inflammation and disrupting epithelial barrier in the intestine of piglets

The intestinal epithelium is the first barrier against food contaminants and is highly sensitive to Fusarium toxins, especially deoxynivalenol (DON) and zearalenone (ZEA). Here, we explored the effects of low doses of DON and/or ZEA in naturally moldy diets on intestinal functions in piglets, including inflammatory responses, epithelial barrier, and microbial composition. Piglets were treated with a control diet (CON), DON diet (1000.6 μg/kg), ZEA diet (269.1 μg/kg), and DON + ZEA diet (1007.5 + 265.4 μg/kg), respectively, for 3 weeks and then switched to the same CON diet for another 2 weeks. In the first period, even the selected low doses of DON or ZEA in the diet resulted in intestinal inflammation, diminish protein expression (claudin-4) and altered gut microbiota populations. Whereas upon switching to the CON diet for another 2 weeks, the deleterious effect of ZEA and DON on IL-1β and Bifidobacterium population could not be recovered. Additionally, combined DON and ZEA negatively affected body weight gain and feed consumption of piglets, as well as shown synergistic effects on evoking pro-inflammatory cytokines contents (TNF-α, IL-1β, and IL-6) and perturbing the cecum microbiota profile (E. coli, Lactobacillus, and Bifidobacterium). Collectively, chronic consumption of DON and ZEA contaminated feed or food, even at low doses, can induce intestinal damage and may have consequences for animal and human health.

Effects of Deoxynivalenol and Zearalenone on the Histology and Ultrastructure of Pig Liver

The purpose of this study was to determine the effects of single and combined administrations of deoxynivalenol (DON) and zearalenone (ZEN) on the histology and ultrastructure of pig liver. The study was performed on immature gilts, which were divided into four equal groups. Animals in the experimental groups received DON at a dose of 12 μg/kg body weight (BW) per day, ZEN at 40 μg/kg BW per day, or a mixture of DON (12 μg/kg BW per day) and ZEN (40 μg/kg BW). The control group received vehicle. The animals were killed after 1, 3, and 6 weeks of experiment. Treatment with mycotoxins resulted in several changes in liver histology and ultrastructure, including: (1) an increase in the thickness of the perilobular connective tissue and its penetration to the lobules in gilts receiving DON and DON + ZEN; (2) an increase in the total microscopic liver score (histology activity index (HAI)) in pigs receiving DON and DON + ZEN; (3) dilatation of hepatic sinusoids in pigs receiving ZEN, DON and DON + ZEN; (4) temporary changes in glycogen content in all experimental groups; (5) an increase in iron accumulation in the hepatocytes of gilts treated with ZEN and DON + ZEN; (6) changes in endoplasmic reticulum organization in the hepatocytes of pigs receiving toxins; (7) changes in morphology of Browicz-Kupffer cells after treatment with ZEN, DON, and DON + ZEN. The results show that low doses of mycotoxins used in the present study, even when applied for a short period, affected liver morphology.

Mycotoxins and the Enteric Nervous System

Mycotoxins are secondary metabolites produced by various fungal species. They are commonly found in a wide range of agricultural products. Mycotoxins contained in food enter living organisms and may have harmful effects on many internal organs and systems. The gastrointestinal tract, which first comes into contact with mycotoxins present in food, is particularly vulnerable to the harmful effects of these toxins. One of the lesser-known aspects of the impact of mycotoxins on the gastrointestinal tract is the influence of these substances on gastrointestinal innervation. Therefore, the present study is the first review of current knowledge concerning the influence of mycotoxins on the enteric nervous system, which plays an important role, not only in almost all regulatory processes within the gastrointestinal tract, but also in adaptive and protective reactions in response to pathological and toxic factors in food.

Proteome changes induced by a short, non-cytotoxic exposure to the mycoestrogen zearalenone in the pig intestine

Intestinal epithelial homeostasis is regulated by a complex network of signaling pathways. Among them is estrogen signaling, important for the proliferation and differentiation of epithelial cells, immune signaling and metabolism. The mycotoxin zearalenone (ZEN) is an estrogen disruptor naturally found in food and feed. The exposure of the intestine to ZEN has toxic effects including alteration of the immune status and is possibly implicated in carcinogenesis, but the molecular mechanisms linked with these effects are not clear. Our objective was to explore the proteome changes induced by a short, non-cytotoxic exposure to ZEN in the intestine using pig jejunal explants. Our results indicated that ZEN promotes little proteome changes, but significantly related with an induction of ERα signaling and a consequent disruption of highly interrelated signaling cascades, such as NF-κB, ERK1/2, CDX2 and HIF1α. The toxicity of ZEN leads also to an altered immune status characterized by the activation of the chemokine CXCR4/SDF-1 axis and an accumulation of MHC-I proteins. Our results connect the estrogen disrupting activity of ZEN with its intestinal toxic effect, associating the exposure to ZEN with cell-signaling disorders similar to those involved in the onset and progression of diseases such as cancer and chronic inflammatory disorders. SIGNIFICANCE: The proteomics results presented in our study indicate that the endocrine disruptor activity of ZEN is able to regulate a cascade of highly inter-connected signaling events essential for the small intestinal crypt-villus cycle and immune status. These molecular mechanisms are also implicated in the onset and progress of intestinal immune disorders and cancer indicating that exposure to ZEN could play an important role in intestinal pathogenesis.

Acute Exposure to Zearalenone Disturbs Intestinal Homeostasis by Modulating the Wnt/β-Catenin Signaling Pathway

The mycotoxin zearalenone (ZEN), which frequently contaminates cereal-based human food and animal feed, is known to have an estrogenic effect. The biological response associated with exposure to ZEN has rarely been reported in organs other than the reproductive system. In the intestine, several studies suggested that ZEN might stimulate molecular changes related to the activation of early carcinogenesis, but the molecular mechanisms behind these events are not yet known. In this study, we investigated gene expression and changes in protein abundance induced by acute exposure to ZEN in the jejunum of castrated male pigs using an explant model. Our results indicate that ZEN induces the accumulation of ERα but not ERβ, modulates Wnt/β-catenin and TGF-β signaling pathways, and induces molecular changes linked with energy sensing and the antimicrobial activity without inducing inflammation. Our results confirm that the intestine is a target for ZEN, inducing changes that promote cellular proliferation and could contribute to the onset of intestinal pathologies.

Correlations between exposure to deoxynivalenol and zearalenone and the immunohistochemical expression of estrogen receptors in the intestinal epithelium and the mRNA expression of selected colonic enzymes in pre-pubertal gilts

Plant-based materials used in the production of pig feed are very often contaminated with deoxynivalenol and zearalenone. Daily intake of small amounts of these mycotoxins with feed induces various subclinical states in gilts and influences different biological processes. The aim of this preclinical study was to determine the correlation between monotonic doses of zearalenone and deoxynivalenol (40 μg/kg body weight and 12 μg/kg body weight, respectively, administered over a period of 42 days) and the immunohistochemical expression of estrogen receptors in the intestinal tract and the mRNA expression of selected colonic enzymes. The immunohistochemical expression of estrogen receptor alpha was observed in the colon, but its intensity varied in different weeks of exposure. A minor increase in estrogen receptor beta expression was noted only in the colon, whereas the expression of cytochrome P450 1A1 enzyme mRNA and mRNA isoform of the glutathione S-transferase π gene decreased. The observed correlations suggest that the risk of loss of control over the biotransformation and biological activity of the parent compounds in distal intestinal mucosa is delayed.

Imbalance in the Blood Concentrations of Selected Steroids in Pre-pubertal Gilts Depending on the Time of Exposure to Low Doses of Zearalenone

Zearalenone (ZEN) is a mycotoxin that not only binds to estrogen receptors, but also interacts with steroidogenic enzymes and acts as an endocrine disruptor. The aim of this study was to verify the hypothesis that low doses, minimal anticipated biological effect level (MABEL), no-observed-adverse-effect level (NOAEL) and lowest-adverse-effect level (LOAEL), of ZEN administered orally for 42 days can induce changes in the peripheral blood concentrations of selected steroid hormones (estradiol, progesterone and testosterone) in pre-pubertal gilts. The experiment was performed on 60 clinically healthy gilts with average BW of 14.5 ± 2 kg, divided into three experimental groups and a control group. Group ZEN5 animals were orally administered ZEN at 5 μg ZEN/kg BW, group ZEN10 - at 10 μg ZEN/kg BW, group ZEN15 - at 15 μg ZEN/kg BW, whereas group C received a placebo. Five gilts from every group were euthanized on analytical dates 1, 2 and 3 (days 7, 14 and 42 of the experiment). Qualitative and quantitative changes in the biotransformation of low ZEN doses were observed. These processes were least pronounced in group ZEN5 (MABEL dose) where ZEN metabolites were not detected on the first analytical date, and where β-ZEL was the predominant metabolite on successive dates. The above was accompanied by an increase in the concentration of estradiol (E2) which, together with "free ZEN", probably suppressed progesterone (P4) and testosterone (T) levels.

The Effect of Low and High Dose Deoxynivalenol on Intestinal Morphology, Distribution, and Expression of Inflammatory Cytokines of Weaning Rabbits

Deoxynivalenol (DON) is a potential pathogenic factor to humans and animals, and intestinal tract is the primary target organ of DON. Data concerning the effects of DON on rabbits are scarce, especially for weaning rabbits. In this study, 45 weaning rabbits (35 d) were randomly and equally assigned into three groups. Group A was fed basic diet, while groups B and C were added DON at 0.5 mg/kg BW/d and 1.5 mg/kg BW/d, respectively, based on the basic diet. The experiment lasted for 24 days and the intestinal morphology, expression, and distribution of several cytokines in intestinal segments have been examined. The results indicated that ADG decreased while F/G increased significantly compared with the control group after DON added at 1.5 mg/kg BW/d. Some of the morphometric parameters (villi length, crypt depth, and goblet cells density) changed after DON was added. Meanwhile, the concentration as well as the expression levels of relative protein and mRNA of IL-1β, IL-2, IL-6, and IL-8 increased significantly. The immunohistochemistry results illustrated that the quantity and distribution of positive cells of inflammatory cytokines were changed after DON was added. In conclusion, the addition of DON damaged the intestinal morphology and changed the distribution and expression of inflammatory cytokines. The toxic effect depended on the dosage of DON.

The impact of low and high doses of acrylamide on the intramural neurons of the porcine ileum

The present study was designed to assess the influence of acrylamide supplementation, in tolerable daily intake (TDI) dose and a dose ten times higher than TDI, on the neurochemical phenotype of the ENS neurons and synthesis of proinflammatory cytokines in the wall of the porcine ileum. The study was performed on 15 juvenile female Danish Landrace pigs, divided into three groups: C group- animals receiving empty gelatine capsules, LD group- animals receiving capsules with the TDI dose (0.5 μg/kg b.w./day) of acrylamide and HD group- animals receiving acrylamide in a dose ten times higher than the TDI (5 μg/kg b.w./day) in a morning meal for 28 days. It was established that supplementation of acrylamide led to an increase in substance P (SP)-, calcitonin gene-related peptide (CGRP)-, galanin (GAL)- and vesicular acetylcholine transporter (VAChT)-like immunoreactive (LI) neurons as well as a decrease in neuronal nitric oxide synthase (nNOS) -like immunoreactivity in all types of ileum intramural plexuses. Moreover, using ELISA method, an increase in the level of proinflammatory cytokines (IL-1β, IL-6 and TNF- α) was noted in the ileum wall. The results suggest that SP, CGRP, GAL, nNOS and VACHT participate in the regulation of inflammatory conditions induced by acrylamide supplementation.

Progress in Mycotoxins Affecting Intestinal Mucosal Barrier Function

Mycotoxins, which are widely found in feed ingredients and human food, can exert harmful effects on animals and pose a serious threat to human health. As the first barrier against external pollutants, the intestinal mucosa is protected by a mechanical barrier, chemical barrier, immune barrier, and biological barrier. Firstly, mycotoxins can disrupt the mechanical barrier function of the intestinal mucosa, by destroying the morphology and tissue integrity of the intestinal epithelium. Secondly, mycotoxins can cause changes in the composition of mucin monosaccharides and the expression of intestinal mucin, which in turn affects mucin function. Thirdly, mycotoxins can cause damage to the intestinal mucosal immune barrier function. Finally, the microbiotas of animals closely interact with ingested mycotoxins. Based on existing research, this article reviews the effects of mycotoxins on the intestinal mucosal barrier and its mechanisms.

The Genotoxicity of Caecal Water in Gilts Exposed to Low Doses of Zearalenone

Zearalenone is a toxic low-molecular-weight molecule that is naturally produced by moulds on crops as a secondary metabolite. The aim of this study was to determine the genotoxicity of caecal water collected successively from the caecal contents of gilts exposed to low doses (LOAEL, NOAEL, and MABEL) of zearalenone. The experiment was performed on 60 clinically healthy gilts with average BW of 14.5 ± 2 kg, divided into three experimental groups and a control group. Group ZEN5 were orally administered ZEN at 5 μg/kg BW, group ZEN10-10 μg ZEN/kg BW and group ZEN15-15 µg ZEN/kg BW. Five gilts from every group were euthanized on analytical dates 1, 2, and 3. Caecal water samples for in vitro analysis were collected from the ileocaecal region. The genotoxicity of caecal water was noted, particularly after date 1 in groups ZEN10 and ZEN15 with a decreasing trend. Electrophoresis revealed the presence of numerous comets without tails in groups C and ZEN5 and fewer comets with clearly expressed tails in groups ZEN10 and ZEN15. The distribution of LLC-PK1 cells ranged from 15% to 20% in groups C and ZEN5, and from 30% to 60% in groups ZEN10 and ZEN15. The analysis of caecal water genotoxicity during exposure to very low doses of ZEN revealed the presence of a counter response and a compensatory effect in gilts.

Mycotoxin levels in the digestive tissues of immature gilts exposed to zearalenone and deoxynivalenol

Most plant materials are contaminated with small doses of Fusarium mycotoxins and its modified forms that exert subclinical toxic effects on humans and animals. The aim of this study was to evaluate the carry-over of zearalenone and deoxynivalenol (pure parent compounds) to intestinal and liver tissues during 6 weeks of exposure to mycotoxins administered per os to gilts. The experiment was performed on 36 gilts with average body weight of 25 ± 2 kg, divided into 2 groups: an experimental group (group E, administered zearalenone at 40 μg/kg BW and deoxynivalenol at 12 μg/kg BW daily with feed) and a control group administered placebo. Tissue saturation with mycotoxins was analysed by liquid chromatography in samples collected at weekly intervals. Six gilts were euthanized in each week of the study. The conducted analyses revealed: (i) a non-uniform increase in zearalenone levels in the duodenum, jejunum, ascending colon and the liver; and (ii) an increase in deoxynivalenol levels, mainly in the ileum, caecum, ascending colon and the transverse colon, and a minor increase in the liver. The degree of tissue saturation was determined by the type of mycotoxin, but not by the time of exposure.