Toxicity of deoxynivalenol and its acetylated derivatives on the intestine: differential effects on morphology, barrier function, tight junction proteins, and mitogen-activated protein kinases

Comparative sensitivity of proliferative and differentiated intestinal epithelial cells to the food contaminant, deoxynivalenol

The intestinal epithelium is a functional and physical barrier formed by a cell monolayer that constantly differentiates from a stem cell in the crypt. This is the first target for food contaminants, especially mycotoxins. Deoxynivalenol (DON) is one of the most prevalent mycotoxins. This study compared the effects of DON (0-100 μM) on proliferative and differentiated intestinal epithelial cells. Three cell viability assays (LDH release, ATP content and neutral red uptake) indicated that proliferative Caco-2 cells are more sensitive to DON than differentiated ones. The establishment of transepithelial electrical resistance (TEER), as a read out of the differentiation process, was delayed in proliferative cells after exposure to 1 μM DON. Transcriptome analysis of proliferative and differentiated exposure to 0-3 μM DON for 24 h revealed 4862 differentially expressed genes (DEG) and indicated an effect of both the differentiation status and the DON treatment. KEGG enrichment analysis indicated involvement of metabolism, ECM receptors and tight junctions in the differentiation process, while ribosome biogenesis, mRNA surveillance, and the MAPK pathway were involved in the response to DON. The number of differentially expressed genes and the amplitude of the effect were higher in proliferative cells exposed to DON than that in differentiated cells. In conclusion, our study shows that proliferative cells are more susceptible than differentiated ones to DON and that the mycotoxin delays the differentiation process.

Mechanism of deoxynivalenol mediated gastrointestinal toxicity: Insights from mitochondrial dysfunction

Deoxynivalenol (DON) is a mycotoxin predominantly produced by Fusarium genus, and widely contaminates cereals and associated products all over the world. The intestinal toxicity of DON is well established. However, intestinal homeostasis involves mitochondria, which has rarely been considered in the context of DON exposure. We summarize the recent knowledge on mitochondria as a key player in maintaining intestinal homeostasis based on their functions in cellular energy metabolism, redox homeostasis, apoptosis, intestinal immune responses, and orchestrated bidirectional cross-talk with gut microbe. In addition, we discuss the pivotal roles of mitochondrial dysfunction in the intestinal toxicity of DON and highlight promising mitochondrial-targeted therapeutics for DON-induced intestinal injury. Recent studies support that the intestinal toxicity of DON is attributed to mitochondrial dysfunction as a critical factor. Mitochondrial dysfunction characterized by failure in respiratory capacities and ROS overproduction has been demonstrated in intestinal cells exposed to DON. Perturbation of mitochondrial respiration leading to ROS accumulation is implicated in the early initiation of apoptosis. DON-induced intestinal inflammatory response is tightly linked to the mitochondrial ROS, whereas immunosuppression is intimately associated with mitophagy inhibition. DON perturbs the orchestrated bidirectional cross-talk between gut microbe and host mitochondria, which may be involved in DON-induced intestinal toxicity.

Evaluation of the mitigation efficacy of a yeast cell wall extract toward deoxynivalenol contaminated diet fed to turbot (Scophthalmus maximus)

Deoxynivalenol (DON) is one of the most common mycotoxins in animal feed worldwide and causes significant threats to the animal health. Increased use of plant ingredients in aquaculture feeds increased the risk of mycotoxin contamination. To evaluate the effects of dietary deoxynivalenol (DON) on growth performance, immune response and intestinal health of turbot and the mitigation efficacy of yeast cell wall extract (YCWE) toward DON, nine isonitrogenous and isolipidic diets were formulated: Diet 1 (control): No DON added; Diets 2-5 or Diets 6-9: 0.5 or 3.0 mg added DON/kg diet + 0%, 0.1%, 0.2%, or 0.4% YCWE, respectively. Results showed that Diet 6 (3 mg/kg DON, 0% YCWE) significantly decreased weight gain, specific growth rate and feed efficiency ratio of fish and reduced immunoglobulin M and complement 4 concentrations in serum. Fish fed Diet 6 presented morphological alterations, lower activity of superoxide dismutase, catalase and total antioxidant capacity but higher malondialdehyde content, lower claudin-4 and occludin expression but higher interleukin-1β expression in intestine. Besides, Diet 6 decreased the abundance of potential helpful bacteria but increased the abundance of potential pathogens in intestine. While, dietary YCWE, especially Diet 8 (3 mg/kg DON, 0.2% YCWE) and 9 (3 mg/kg DON, 0.4% YCWE), markedly improved growth performance and immune response and enhanced the intestinal health of turbot. In conclusion, dietary YCWE could mitigate the toxic effects induced by DON in turbot, and could be used as an effective strategy to control DON contamination in fish feed.

Mechanisms of deoxynivalenol (DON) degradation during different treatments: a review

Deoxynivalenol (DON) is one of the main trichothecenes, that causes health-related issues in humans and animals and imposes considerable financial loss to the food industry each year. Numerous treatments have been reported in the literature on the degradation of DON in food products. These treatments include thermal, chemical, biological/enzymatic, irradiation, light, ultrasound, ozone, and atmospheric cold plasma treatments. Each of these methods has different degradation efficacy and degrades DON by a distinct mechanism, which leads to various degradation byproducts with different toxicity. This manuscript focuses to review the degradation of DON by the aforementioned treatments, the chemical structure and toxicity of the byproducts, and the degradation pathway of DON. Based on the type of treatment, DON can be degraded to norDONs A-F, DON lactones, and ozonolysis products or transformed into de-epoxy deoxynivalenol, DON-3-glucoside, 3-acetyl-DON, 7-acetyl-DON, 15-acetyl-DON, 3-keto-DON, or 3-epi-DON. DON is a major problem for the grain industry and the studies focusing on DON degradation mechanisms could be helpful to select the best method and overcome the DON contamination in grains.

Fate of regulated, masked, emerging mycotoxins and secondary fungal metabolites during different large-scale maize dry-milling processes

The use of maize in the food chain could be mainly limited due to its contamination by mycotoxins. As scarce information is available, the current study is aimed at collecting new data on the co-occurrence and the fate of the most frequent masked, modified and emerging mycotoxins and other second fungal metabolites in maize food products and by-products. Three maize lots, obtained in different growing seasons, were processed using two different degermination processes, a dry-degermination system or a tempering-degermination one, in order to compare the interaction between mycotoxins and the dry-milling management system. Whole grain before and after cleaning, and all the products and the by-products were sampled twice for each lot and were subjected to a multi-mycotoxin LC-MS/MS analysis. More than 30 mycotoxins and other fungal metabolites, including masked or modified forms, co-occurred in all the maize milling fractions. Grain cleaning reduced all the detected fungal metabolites by 1.2-2 times, compared to the grain before cleaning. Animal feed flour showed the highest content of almost all the mycotoxins and fungal metabolites, with a consequent negative impact on animal health. Considering that for all the mycotoxins and fungal metabolites an inverse relationship with particle size was observed, flaking grits represented the healthiest maize products with the least contamination level, while the abatement was always lower for maize flour. Furthermore, the metabolites were variably redistributed in the maize fractions. The total aflatoxins, kojic acid, deoxynivalenol and its modified form, culmorin, and its associated forms, butenolide, fusaproliferin, fusaric acid, fusarinolic acid and, in some cases, zearalenone and its modified forms, and fusarin C were found to be concentrated significantly in the germ. Some of them also had a greater permanence in the maize food fractions and a weaker decontamination, both of which point to a higher risk of exposure for the end consumers. The co-occurrence of a such a high number of mycotoxins and fungal metabolites and their different fates during the dry-milling process have never been described before.

Species Differences in in vitro and Estimated in vivo Kinetics for Intestinal Microbiota Mediated Metabolism of Acetyl-deoxynivalenols

SCOPE

Deoxynivalenol (DON) and its acetylated derivatives 3-acetyl-DON (3-Ac-DON) and 15-acetyl-DON (15-Ac-DON) are important mycotoxins of concern in the modern food chain.

METHODS AND RESULTS

The present study reveals that the rate of de-acetylation in in vitro anaerobic fecal incubations decreased in the order rat > mouse > human > pig for 3-Ac-DON, and mouse > human > rat > pig for 15-Ac-DON. The ratio between the de-acetylation rate of 3-Ac-DON and 15-Ac-DON varies with the species. Scaling of the kinetic parameters to the in vivo situation results in catalytic efficiencies decreasing in the order human > rat > pig > mouse for 3-Ac-DON and human > pig > rat > mouse for 15-Ac-DON. The results obtained indicate that in mice, 3-Ac-DON can be fully deconjugated while 15-Ac-DON cannot. In rats, pigs, and humans, both 3-Ac-DON and 15-Ac-DON can be totally transformed by gut fecal microbiota during the estimated intestinal residence time. A correlation analysis between the deacetylation rate and the relative abundance of the microbiome suggests Lachnospiraceae may be involved in the deacetylation process.

CONCLUSION

It is concluded that interspecies differences in deacetylation of acetylated DONs exist but that in risk assessment assumption of complete intestinal deconjugation provides an adequate approach.

Feed-Based Multi-Mycotoxin Occurrence in Smallholder Dairy Farming Systems of South Africa: The Case of Limpopo and Free State

Mycotoxin contamination of feed does not only cut across food and feed value chains but compromises animal productivity and health, affecting farmers, traders and consumers alike. To aid in the development of a sustainable strategy for mycotoxin control in animal-based food production systems, this study focused on smallholder farming systems where 77 dairy cattle feed samples were collected from 28 smallholder dairy establishments in the Limpopo and Free State provinces of South Africa between 2018 and 2019. Samples were analyzed using a confirmatory UHPLC–MS/MS (Ultra-high performance liquid chromatography-tandem mass spectrometry) method validated for simultaneous detection of 23 mycotoxins in feeds. Overall, mycotoxins assessed were detected across samples with 86% of samples containing at least one mycotoxin above respective decision limits; up to 66% of samples were found to be contaminated with at least three mycotoxins. Findings demonstrated that deoxynivalenol, sterigmatocystin, alternariol and enniatin B were the most common mycotoxins, while low to marginal detection rates were observed for all other mycotoxins with none of the samples containing fusarenon-X, HT-2-toxin and neosolaniol. Isolated cases of deoxynivalenol (maximum: 2385 µg/kg), aflatoxins (AFB₁ (maximum: 30.2 µg/kg)/AFG₁ (maximum: 23.1 µg/kg)), and zearalenone (maximum: 1793 µg/kg) in excess of local and European regulatory limits were found. Kruskal–Wallis testing for pairwise comparisons showed commercial feed had significantly higher contamination for deoxynivalenol and its acylated derivatives, ochratoxin A and fumonisins (FB₁ and FB₂), whereas forages had significantly higher alternariol; in addition to significantly higher fumonisin B₁ contamination for Limpopo coupled with significantly higher enniatin B and sterigmatocystin for Free State. Statistically significant Spearman correlations (p < 0.01) were also apparent for ratios for deoxynivalenol/fumonisin B₁ (r_s = 0.587) and zearalenone/alternariol methylether (r_s = 0.544).

Deoxynivalenol Induces Inflammation in the Small Intestine of Weaned Rabbits by Activating Mitogen-Activated Protein Kinase Signaling

Deoxynivalenol (DON) can activate related signaling pathways and induce gastrointestinal disorders. Based on the results of previous studies, this study tried to explore the relationship between DON-induced intestinal inflammation of weaned rabbits and the ERK-p38 signaling pathway. Forty-five weaned rabbits were divided into three treatments: control, LD and HD group. All rabbits were treated with diet containing a same nutrient content, but animals in the LD and HD groups were additionally administered DON via drinking water at 0.5 and 1.5 mg/kg b.w./d, respectively. The protocol consisted of a total feeding period of 31 days, including a pre-feeding period of 7 days. Western blotting, qRT-PCR, and immunohistochemistry were applied for analysis the expression of protein and mRNA of extracellular signal-regulated kinase (ERK), p38, double-stranded RNA-activated protein kinase (PKR), and hematopoietic cell kinase (Hck) in the duodenum, jejunum, and ileum of rabbits, as well as the distribution of positive reactants. The results proved that DON intake could enhance the levels of inflammatory factors in serum and damage the intestinal structure barrier of rabbits. Meanwhile, DON addition can stimulate the protein and mRNA expression for ERK, p38, PKR, and Hck in the intestine of rabbits, especially in the duodenum, as well as expand the distribution of positive reactants, in a dose-dependent manner.

Maternal dietary linoleic acid altered intestinal barrier function in domestic pigeons (Columba livia)

Linoleic acid (LA) is predominantly essential for poultry. Poultry lacking LA show retarded growth and reduced disease resistance. Intestinal barrier function plays an important role in pigeon squab growth, whereas research on the effects of LA on intestinal health in altrices is scant. Considering that squabs are fed by their parents, the study aimed to explore the effects of maternal dietary LA on intestinal morphology, tight junction proteins, immune cytokines and microbial flora in squabs. A completely randomised design with a control group, 1 % LA supplementation group, 2 % LA supplementation group and 4 % LA supplementation group was used. Six squabs from each treatment were randomly sampled at 21 d post-hatching. The results indicated that LA supplementation improved intestinal morphology, as reflected by increased villus height, villus area and the ratio of villi to crypts. Also, 1 % LA supplementation elevated the density of goblet cells in the intestine and strengthened tight junctions by up-regulating claudin-3 and occludin gene expression but down-regulating claudin-2 gene expression. Moreover, 1 % LA supplementation reduced the secretion of proinflammatory cytokines and partly increased anti-inflammatory cytokines. The intestinal microbial diversity in the 1 % LA supplementation group was higher than that in the other groups. As beneficial bacteria, Butyrivibrio was the biomarker of 1 % LA supplementation. However, excessive (4 %) LA supplementation led to adverse impacts on intestinal immunity and microbiota. In conclusion, maternal dietary LA might alter intestinal barrier function in pigeon squabs in a dose-dependent manner. Supplementation with 1 % LA was suggested in parental pigeons.

Effect of chlorogenic acid on alleviating inflammation and apoptosis of IPEC-J2 cells induced by deoxyniyalenol

Deoxynivalenol (DON) is extensively detected in many kinds of foods and feeds to harm human and animal health. This research aims to investigate the effect of chlorogenic acid (CGA) on alleviating inflammation and apoptosis of swine jejunal epithelial cells (IPEC-J2) triggered by DON. The results demonstrated that cell viability was decreased when DON concentrations increased or incubation time expanded. The pretreatment with CGA (40 μg/mL) for 1 h increased cell viability, decreased lactate dehydrogenase (LDH) release and apoptosis in cells triggered by DON at 0.5 μg/mL for 6 h, compared with the DON alone-treated cells. Moreover, the mRNA abundances of IL-8, IL-6, TNF-α, COX-2, caspase-3, Bax and ASCT2 genes, and protein expressions of COX-2, Bax and ASCT2 were significantly down-regulated; while the mRNA abundances of ZO-1, claudin-1, occludin, PePT1 and GLUT2 genes, and protein expressions of ZO-1, claudin-1 and PePT1 were significantly up-regulated in the CGA + DON group, compared with the DON alone group. This study indicated that CGA pretreatment alleviated cytotoxicity, inflammation and apoptosis in DON-triggered IPEC-J2 cells, and protected intestinal cell integrity from DON damages.

Molecular Aspects of Mycotoxins-A Serious Problem for Human Health

Mycotoxins are toxic fungal secondary metabolities formed by a variety of fungi (moulds) species. Hundreds of potentially toxic mycotoxins have been already identified and are considered a serious problem in agriculture, animal husbandry, and public health. A large number of food-related products and beverages are yearly contaminated by mycotoxins, resulting in economic welfare losses. Mycotoxin indoor environment contamination is a global problem especially in less technologically developed countries. There is an ongoing effort in prevention of mould growth in the field and decontamination of contaminated food and feed in order to protect human and animal health. It should be emphasized that the mycotoxins production by fungi (moulds) species is unavoidable and that they are more toxic than pesticides. Human and animals are exposed to mycotoxin via food, inhalation, or contact which can result in many building-related illnesses including kidney and neurological diseases and cancer. In this review, we described in detail the molecular aspects of main representatives of mycotoxins, which are serious problems for global health, such as aflatoxins, ochratoxin A, T-2 toxin, deoxynivalenol, patulin, and zearalenone.

Fast Deoxynivalenol Determination in Cereals Using a White Light Reflectance Spectroscopy Immunosensor

Deoxynivalenol (DON) is a mycotoxin produced by certain Fusarium species and found in a high percentage of wheat and maize grains cultured worldwide. Although not so toxic as other mycotoxins, it exhibits both chronic and acute toxicity, and therefore methods for its fast and accurate on-site determination are highly desirable. In the current work, we employ an optical immunosensor based on White Light Reflectance Spectroscopy (WLRS) for the fast and sensitive immunochemical label-free determination of DON in wheat and maize samples. The assay is completed in 12 min and has a quantification limit of 2.5 ng/mL in buffer corresponding to 125 μg/kg in whole grain which is lower than the maximum allowable concentrations set by the regulatory authorities for grains intended for human consumption. Several extraction protocols have been compared, and the highest recovery (>90%) was achieved employing distilled water. In addition, identical calibration curves were received in buffer and wheat/maize extraction matrix providing the ability to analyze the grain samples using calibrators in buffer. Recoveries of DON from spiked wheat and maize grain samples ranged from 92.0(±4.0) to 105(±4.0)%. The analytical performance of the WLRS immunosensor, combined with the short analysis time and instrument portability, supports its potential for on-site determinations.

Ruminant Mycotoxicosis: An Update

This review focuses on factors associated with mold production in feedstuffs and major mycotoxins affecting ruminants in North America. Ruminants are often considered less sensitive to mycotoxins owing to rumen microflora metabolism to less toxic compounds. However, ruminants occupy wide agricultural niches that expose animals to diverse toxins under widely different environmental and nutritional conditions. Often the moldy and potentially highly contaminated feeds end up at feedlots. Less than optimal feedstuffs creating suboptimal rumen microbial flora could result in decreased ruminal capacity to detoxify certain mycotoxins and adverse effects. Numerous mycotoxins and clinical effects in ruminants are discussed.

3-Acetyldeoxynivalenol induces lysosomal membrane permeabilization-mediated apoptosis and inhibits autophagic flux in macrophages

3-Acetyldeoxynivalenol (3-Ac-DON), the acetylated derivative of deoxynivalenol (DON), has been reported to be coexisted with DON in various cereal grains. Ingestion of grain-based food products contaminated by 3-Ac-DON might exert deleterious effects on the health of both humans and animals. However, the biological toxicity of 3-Ac-DON on macrophages and the underlying mechanisms remain largely unknown. In the present study, we showed that RAW 264.7 macrophages treated with 0.75 or 1.50 μg/mL of 3-Ac-DON resulted in DNA damage and the related cell cycle arrest at G1 phase and cell death, activation of the ribotoxic stress and the endoplasmic reticulum (ER) stress responses. The 3-Ac-DON-induced cell death was accompanied by a protective autophagy, because gene silencing of Atg5 using the small interfering RNA enhanced cell death. Results of further experiments revealed a role for lysosomal membrane permeabilization in the 3-Ac-DON triggered inhibition of autophagic flux. Additional work also showed that increased lysosomal biogenesis and leakage of cathepsin B (CTSB) from lysosomes to cytosol was critical for the 3-Ac-DON-induced cell death. Importantly, 3-Ac-DON-induced DNA damage and cell death were rescued by CA-074-me, a CTSB inhibitor. Collectively, these results indicated a critical role of lysosomal membrane permeabilization in the 3-Ac-DON-induced apoptosis of RAW 264.7 macrophages.

Co-Occurrence and Levels of Mycotoxins in Fish Feeds in Kenya

This study determined the presence, levels and co-occurrence of mycotoxins in fish feeds in Kenya. Seventy-eight fish feeds and ingredients were sampled from fish farms and fish feed manufacturing plants and analysed for 40 mycotoxins using high-performance liquid chromatography-high resolution mass spectrometry. Twenty-nine (73%) mycotoxins were identified with 76 (97%) samples testing positive for mycotoxins presence. Mycotoxins with the highest prevalences were enniatin B (91%), deoxynivalenol (76%) and fumonisin B1 (54%) while those with the highest maximum levels were sterigmatocystin (<30.5-3517.1 µg/kg); moniliformin (<218.9-2583.4 µg/kg) and ergotamine (<29.3-1895.6 µg/kg). Mycotoxin co-occurrence was observed in 68 (87%) samples. Correlations were observed between the fumonisins; enniatins B and zearalenone and its metabolites. Fish dietary exposure estimates ranged between <0.16 and 43.38 µg/kg body weight per day. This study shows evidence of mycotoxin presence and co-occurrence in fish feeds and feed ingredients in Kenya. Fish exposure to these levels of mycotoxins over a long period of time may lead to adverse health effects due to their possible additive, synergistic or antagonist toxic effects. Measures to reduce fish feed mycotoxin contamination should be taken to avoid mycotoxicosis in fish and subsequently in humans and animals through residues.

Mycotoxin Deoxynivalenol Has Different Impacts on Intestinal Barrier and Stem Cells by Its Route of Exposure

The different effects of deoxynivalenol (DON) on intestinal barrier and stem cells by its route of exposure remain less known. We explored the toxic effects of DON on intestinal barrier functions and stem cells after DON microinjection (luminal exposure) or addition to a culture medium (basolateral exposure) using three-dimensional mouse intestinal organoids (enteroids). The influx test using fluorescein-labeled dextran showed that basolateral DON exposure (1 micromolar (µM) disrupted intestinal barrier functions in enteroids compared with luminal DON exposure at the same concentration. Moreover, an immunofluorescence experiment of intestinal epithelial proteins, such as E-cadherin, claudin, zonula occludens-1 (ZO-1), and occludin, exhibited that only basolateral DON exposure broke down intestinal epithelial integrity. A time-lapse analysis using enteroids from leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5)-enhanced green fluorescence protein (EGFP) transgenic mice and 5-ethynyl-2-deoxyuridine (EdU) assay indicated that only the basolateral DON exposure, but not luminal DON exposure, suppressed Lgr5⁺ stem cell count and proliferative cell ratio, respectively. These results revealed that basolateral DON exposure has larger impacts on intestinal barrier function and stem cells than luminal DON exposure. This is the first report that DON had different impacts on intestinal stem cells depending on the administration route. In addition, RNA sequencing analysis showed different expression of genes among enteroids after basolateral and luminal DON exposure.

The Effects of Deoxynivalenol on the Ultrastructure of the Sacculus Rotundus and Vermiform Appendix, as Well as the Intestinal Microbiota of Weaned Rabbits

Deoxynivalenol (DON) is a mycotoxin found in grains that poses a potential threat to human and animal health, and the gastrointestinal tract is the primary target organ. There are few studies focused on the toxicology of DON to rabbits, especially on the relation among DON, microbiota, and the gut-associated lymphoid tissue. A total of 30 weaned rabbits (35 d) were evenly divided into the control group and DON group (1.5 mg/kg bodyweight (BW)) based on their body weight. After a 24-day trial, the ultrastructures of the sacculus rotundus and vermiform appendix were observed using a scanning electron microscope and transmission electron microscopy. The morphology and microflora in the ileum, caecum, and colon were also examined. The results proved that the ultrastructure of the sacculus rotundus and vermiform appendix, as well as the integrity of the intestinal barrier (especially for the ileum), were impaired after DON was administrated to the rabbits. Compared to the control group, the relative abundance and diversity of the microflora decreased in all three intestinal segments in the DON group, particularly in the ileum and caecum. In conclusion, the toxic effect of DON on weaned rabbits may be performed by destroying the structure of the sacculus rotundus and vermiform appendix, as well as affecting the structure and diversity of the intestinal flora.

Decrease in immune function and the role of mitogen-activated protein kinase (MAPK) overactivation in apoptosis during T lymphocytes activation induced by zearalenone, deoxynivalenol, and their combinations

Currently there are few reports on the combined immunotoxicity of zearaleone (ZEA) and deoxynivalenol (DON). Since the two coexist naturally, it is necessary to understand the immunotoxicity caused by the two mycotoxins alone and in combination. To examine T lymphocytes activation and immune effect during activation, we used mouse primary spleen T lymphocytes as the experimental material and concanavalin (Con A) as the stimulator. The effects of ZEA, DON, and their combined exposure on T lymphocytes immune related function and the relationship between the activation of the mitogen-activated protein kinase (MAPK) signaling pathway and mycotoxin induced T lymphocytes apoptosis were studied in vitro. Specifically, T lymphocytes were isolated from primary mouse splenic lymphocytes, activated by Con A and then exposed to different concentrations of ZEA, DON, and their combinations. Our results showed that ZEA and DON alone and their combinations (20:1) can decrease the cell viability of T lymphocytes activated by Con A. The inhibitory effect of the combined groups was greater than that of the single mycotoxins, showing a synergistic effect. In addition, single or combined mycotoxins can lead to intracellular and surface ultrastructure damage of T lymphocytes, inhibit the expression of CD25 and CD278 and inhibit the synthesis of effect molecules poreforming protein (PFP), granzyme A (GZMA), and tumor necrosis factor-α (TNF-α). Meanwhile, the single mycotoxin or combined mycotoxins can promote the apoptosis of T lymphocytes which was accompanied by the overactivation of MAPK. After using the inhibitors of extracellular regulated protein kinases (ERK) and c-Jun N-terminal kinase (JNK) in the MAPK pathway, we found that the apoptosis of the cells induced by the ZEA was significantly decreased, and the apoptosis of the cells induced by DON had no significant changes. This suggests that the activation of MAPK induced by ZEA can promote the apoptosis of T lymphocytes, but the activation of MAPK induced by DON is not directly related to T cell apoptosis.

The food contaminant, deoxynivalenol, modulates the Thelper/Treg balance and increases inflammatory bowel diseases

The incidence of inflammatory bowel diseases (IBD) is increasing in both Western and developing countries. IBD are multifactorial disorders involving complex interactions between genetic, immune, and environmental factors such as exposure to food contaminants. Deoxynivalenol (DON) is the most prevalent mycotoxin that contaminates staple food and induces intestinal breakdown and inflammatory response. To delineate the role of DON oral exposure in IBD, we used a Dextran sulfate sodium (DSS) colitis model in rats fed with a DON-contaminated diet or a control diet for 4 weeks. Colitis was induced in the 4th week by increasing concentrations of DSS in the drinking water (0, 2, 3 or 5%). DON exacerbated body weight loss and accelerated the appearance of symptoms in animals treated with DSS. DON increased morphological damage, pro-inflammatory markers (myeloperoxidase, CXCL-1 and IL-1β) and immune cell responses. In lamina propria of the rat with colitis, DON increased adaptive and innate immune responses after anti-CD3/28 or LPS stimulation, respectively. In the spleen, DON increased IFNγ secretion and reduced Treg populations. Interestingly, De-epoxy-DON (DOM-1) a detoxified form of DON did not have any consequences on colitis. These results suggest that DON is a risk factor in the onset of IBD.

Challenges Associated with Byproducts Valorization-Comparison Study of Safety Parameters of Ultrasonicated and Fermented Plant-Based Byproducts

In order to promote the efficient use of byproducts from the production of plant-based beverages, which still contain a large amount of nutritional and functional compounds, microbiological and chemical safety characteristics should be evaluated and, if needed, improved. Many challenges are associated with byproducts valorization, and the most important ones, which should be taken into account at the further steps of valorization, are biological and chemical safety. For safety improving, several technological treatments (biological, physical etc.) can be used. In this study, the influence of low-frequency ultrasonication (US) and fermentation with Lactobacillus casei LUHS210 strain, as physical and biotechnological treatments, on the safety characteristics of the byproducts (BYs) from the processing of rice, soy, almond, coconut, and oat drinks was compared. Ultrasonication, as well as fermentation, effectively improved the microbiological safety of BYs. Ultrasonication and fermentation reduced the concentration of deoxynivalenol, on average, by 24% only in soy BYs. After fermentation, 15-acetyldeoxynivalenol was formed in all samples (<12 µg kg-1), except for soy BYs. The lowest total biogenic amines content was found in fermented rice BYs and ultrasonicated coconut BYs. When comparing untreated and fermented BYs, significant changes in macro- and micro-elements content were found. Ultrasonication at 37 kHz did not significantly influence the concentrations of macro- and micro-elements, while fermentation affected most of the essential micro-elements. Consequently, while ultrasonication and fermentation can enhance the safety of BYs, the specific effects must be taken into account on biogenic amines, mycotoxins, and micro and macro elements.

Versicolorin A, a precursor in aflatoxins biosynthesis, is a food contaminant toxic for human intestinal cells

Aflatoxin B₁ (AFB₁) is the most potent carcinogen among mycotoxins. Its biosynthesis involves the formation of versicolorin A (VerA), whose chemical structure shares many features with AFB₁. Our data revealed significant levels of VerA in foodstuff from Central Asia and Africa. Given this emerging food risk, it was of prime interest to compare the toxic effects of the two mycotoxins against cells originating from the intestinal tract. We used human colon cell lines (Caco-2, HCT116) to investigate the cytotoxic process induced by the two mycotoxins. Contrary to AFB₁, a low dose of VerA (1 µM) disturbed the expression level of thousands of genes (18 002 genes). We show that the cytotoxic effects of low doses of VerA (1-20 µM) were stronger than the same low doses of AFB₁ in both Caco-2 and HCT116 cell lines. In Caco-2 cells, VerA induced DNA strand breaks that led to apoptosis and reduced DNA replication of dividing cells, consequently inhibiting cell proliferation. Although VerA was able to induce the p53 signaling pathway in p53 wild-type HCT116 cells, its toxicity process did not mainly rely on p53 expression since similar cytotoxic effects were also observed in HCT116 cells that do not express p53. In conclusion, this study provides evidence of the risk of food contamination by VerA and shed light on its toxicological effect on human colon cells.

Metabolomic profiling reveals similar cytotoxic effects and protective functions of quercetin during deoxynivalenol- and 15-acetyl deoxynivalenol-induced cell apoptosis

Among the family of mycotoxins of deoxynivalenol (DON) detected in nature, high proportions of 15-acetyldeoxynivalenol (15ADON) co-occur with the prototype DON and increase the combined exposure and synergistic health risks. The current study aimed to explore the mechanisms underlying the toxicity of 15ADON and compare them with those of DON. As the natural flavonoid compound quercetin (QUE) possesses antioxidant properties, we also aimed to determine the antioxidant effects of QUE on the tested mycotoxins. First, the global metabolomics approach was applied and showed that the metabolites produced from 15ADON or DON were almost identical, while QUE reversed the changes in the levels of key metabolites. Specifically, both DON and 15ADON activated the cell apoptosis pathway mediated by p38 and JNK, but inhibited the cell survival pathway mediated by ERK1/2 in GES-1 cells. Simultaneously, 15ADON induced FOXO3a nuclear translocation, similar to the results described for DON in our recent report. Furthermore, the addition of QUE appeared to counteract the detrimental effects of 15ADON and DON. We observed the effects of QUE treatment on mutant yeast strains with defects in their antioxidant system. More interestingly, QUE also substantially restored the increased ROS levels and the inhibited the growth rate following exposure to the mycotoxins DON and 15ADON. The data reported here support the hypothesis that QUE rescues the toxic effects of DON or 15ADON due to the similar mechanisms of DON and 15ADON toxicity.

Natural Occurrence of Deoxynivalenol and Its Acetylated Derivatives in Chinese Maize and Wheat Collected in 2017

Deoxynivalenol (DON), along with 3-acetyl-deoxynivalenol (3-ADON) and 15-acetyl-deoxynivalenol (15-ADON), occur in grains and cereal products and is often hazardous to humans and livestock. In this study, 579 wheat samples and 606 maize samples intended for consumption were collected from China in 2017 and analyzed to determine the co-occurrence of type-B trichothecenes (DON, 3-ADON, and 15-ADON). All the wheat samples tested positive for DON, while 99.83% of the maize samples were DON-positive with mean DON concentrations of 165.87 and 175.30 μg/kg, respectively. Per the Chinese standard limits for DON, 3.63% of wheat and 2.97% of the maize samples were above the maximum limit of 1000 μg/kg. The DON derivatives (3-ADON and 15-ADON) were less frequently found and were present at lower levels than DON in wheat. 3-ADON and 15-ADON had incidences of 13.53% and 76.40%, respectively, in maize. By analyzing the distribution ratio of DON and its derivatives in wheat and maize, DON (95.51%) was the predominant toxin detected in wheat samples, followed by 3.97% for the combination of DON + 3-ADON, while DON + 3-ADON + 15-ADON and DON + 15-ADON were only found in 0.17% and 0.35% of wheat samples, respectively. Additionally, a large amount of the maize samples were contaminated with DON + 15-ADON (64.19%) and DON (22.11%). The samples with a combination of DON + 3-ADON and DON + 3-ADON + 15-ADON accounted for 1.32% and 12.21%, respectively. Only one maize sample did not contain all three mycotoxins. Our study shows the necessity of raising awareness of the co-occurrence of mycotoxin contamination in grains from China to protect consumers from the risk of exposure to DON and its derivatives.

Reduced toxicity of 3-epi-deoxynivalenol and de-epoxy-deoxynivalenol through deoxynivalenol bacterial biotransformation: In vivo analysis in piglets

Ingestion of deoxynivalenol (DON), one of the most common mycotoxin contaminants of cereals, leads to adverse effects for animal and human health. Bacterial biotransformation is a strategy to mitigate the toxicity of this mycotoxin. The present study aims to evaluate the toxicity of two bacterial biotranformation products of DON: 3-epi-deoxynivalenol (3-epi-DON) and de-epoxy-deoxynivalenol (DOM-1) through zootechnical, hematological, histological and immunological assays. Twenty-four 4-weeks-old piglets received a control diet or a diet contaminated with 3 mg kg^-1 DON, DOM-1, or 3-epi-DON for 7 days. Sample tissues were collected for histomorphometrical analysis, expression of cytokines and cell protein junctions. The zootechnical and hematological parameters were not modulated by any treatment. Ingestion of DON induced histological alterations in the intestine, liver and lymphoid organs, as well as an overexpression of pro-inflammatory cytokines, E-cadherin and occludin. These changes were not observed in piglets receiving the DOM-1 and 3-epi-DON contaminated diets. Pigs fed 3-epi-DON contaminated diet showed an increase in IgM levels in comparison with other diets, while no change was observed in IgA and IgG levels among the diets. Our results indicate that DOM-1 and 3-epi-DON are not toxic for piglets; thus bacterial biotransformation seems to be a sustainable alternative to reduce mycotoxin toxicity.

Deoxynivalenol Induces Inflammation in IPEC-J2 Cells by Activating P38 Mapk And Erk1/2

Fusarium-derived mycotoxin deoxynivalenol (DON) usually induces diarrhea, vomiting and gastrointestinal inflammation. We studied the cytotoxic effect of DON on porcine small intestinal epithelium using the intestinal porcine epithelial cell line IPEC-J2. We screened out differentially expressed genes (DEGs) using RNA-seq and identified 320 upregulated genes and 160 downregulated genes. The enrichment pathways of these DEGs focused on immune-related pathways. DON induced proinflammatory gene expression, including cytokines, chemokines and other inflammation-related genes. DON increased IL1A, IL6 and TNF-α release and DON activated the phosphorylation of extracellular signal-regulated kinase-1 and-2 (ERK1/2), JUN N-terminal kinase (JNK) and p38 MAPK. A p38 inhibitor attenuated DON-induced IL6, TNF-α, CXCL2, CXCL8, IL12A, IL1A, CCL20, CCL4 and IL15 production, while an ERK1/2 inhibitor had only a small inhibitory effect on IL15 and IL6. An inhibitor of p38 MAPK decreased the release of IL1A, IL6 and TNF-α and an inhibitor of ERK1/2 partly attenuated protein levels of IL6. These data demonstrate that DON induces proinflammatory factor production in IPEC-J2 cells by activating p38 and ERK1/2.

1H-NMR metabolomics response to a realistic diet contamination with the mycotoxin deoxynivalenol: Effect of probiotics supplementation

Low-level contamination of food and feed by deoxynivalenol (DON) is unavoidable. We investigated the effects of subclinical treatment with DON, and supplementation with probiotic yeast Saccharomyces cerevisiae boulardii I1079 as a preventive strategy in piglets. Thirty-six animals were randomly assigned to either a control diet, a diet contaminated with DON (3 mg/kg), a diet supplemented with yeast (4 × 10⁹ CFU/kg), or a DON-contaminated diet supplemented with yeast, for four weeks. Plasma and tissue samples were collected for biochemical analysis,¹H-NMR untargeted metabolomics, and histology. DON induced no significant modifications in biochemical parameters. However, lesion scores were higher and metabolomics highlighted alterations of amino acid and 2-oxocarboxylic acid metabolism. Administering yeast affected aminoacyl-tRNA synthesis and amino acid and glycerophospholipid metabolism. Yeast supplementation of piglets exposed to DON prevented histological alterations, and partial least square discriminant analysis emphasised similarity between the metabolic profiles of their plasma and that of the control group. The effect on liver metabolome remained marginal, indicating that the toxicity of the mycotoxin was not eliminated. These findings show that the ¹H-NMR metabolomics profile is a reliable biomarker to assess subclinical exposure to DON, and that supplementation with S. cerevisiae boulardii increases the resilience of piglets to this mycotoxin.

Deoxynivalenol globally affects the selection of 3' splice sites in human cells by suppressing the splicing factors, U2AF1 and SF1

Deoxynivalenol (DON) is one of the most abundant mycotoxins and has adverse effects on several biological processes, posing risks of protein synthesis-disrupting effects and ribotoxic response. Therefore, chronic exposure to DON would fundamentally reshape the global expression pattern. Whether DON causes toxic effects on mRNA splicing, a fundamental biological process, remains unclear. In this study, we found that administration of the relative low dosage of DON dramatically changed the alternative splicing of pre-mRNA in HepG2 cells. The overall number of transcripts with aberrant selection of 3' splice sites was significantly increased in DON-exposed HepG2 cells. This effect was further confirmed in two other human cell lines, HEK293 and Caco-2, suggesting that this DON-induced alteration in splicing patterns was universal in human cells. Among these DON-induced changes in alternative splicing, the expression levels of two related splicing factors, SF1 and U2AF1, which are essential for 3' splice site recognitions, were strongly suppressed. Overexpression of either of the two splicing factors strongly alleviated the DON-induced aberrant selection of 3' splice sites. Moreover, SF1 was required for human cell proliferation in DON exposure, and the restoration of SF1 expression partially reinstated the proliferation potential for DON-treated cells. In conclusion, our study suggests that DON, even at a low dosage, has great potential to change gene expression globally by affecting not only protein synthesis but also mRNA processing in human cells.

Biodegradation of Deoxynivalenol by a Novel Microbial Consortium

Deoxynivalenol (DON), a common mycotoxin of type B trichothecene, is produced mainly by several Fusarium species. DON causes great losses in farming and poses severe safety risks to human and animal health. Thus, DON contamination in cereals and DON toxicity are of worldwide concern. In this study, we screened the bacterial consortium C20, which efficiently degraded almost 70 μg ml⁻¹ DON within 5 days. The bacterial consortium also had the ability to degrade 15-acetyl-DON, 3-acetyl-DON, and T-2 toxin. The bacterial consortium C20 was able to degrade DON under a wide range of pH and temperature conditions. The optimal temperature and pH for DON degradation were 30°C and pH 8.0, respectively. The bacterial consortium C20 comprised of different bacterial genera, and several strains were found to significantly increase when cultured in Mineral Medium with 100 μg ml⁻¹ DON based on the analysis of the sequences of the hypervariable V3-V4 region of the 16S rRNA gene. 3-keto-DON was confirmed as a degradation product of DON by liquid chromatography/time-of-flight/mass spectrometry (LC-TOF-MS) and nuclear magnetic resonance (NMR) analyses. The results indicated that the bacterial consortium C20 is a potential candidate for the biodegradation of DON in a safe and environmentally friendly manner.

Schisandrin A protects intestinal epithelial cells from deoxynivalenol-induced cytotoxicity, oxidative damage and inflammation

Extensive research has revealed the association of continued oxidative stress with chronic inflammation, which could subsequently affect many different chronic diseases. The mycotoxin deoxynivalenol (DON) frequently contaminates cereals crops worldwide, and are a public health concern since DON ingestion may result in persistent intestinal inflammation. There has also been considerable attention over the potential of DON to provoke oxidative stress. In this study, the cytoprotective effect of Schisandrin A (Sch A), one of the most abundant active dibenzocyclooctadiene lignans in the fruit of Schisandra chinensis (Turcz.) Baill (also known as Chinese magnolia-vine), was investigated in HT-29 cells against DON-induced cytotoxicity, oxidative stress and inflammation. Sch A appeared to protect against DON-induced cytotoxicity in HT-29 cells, and significantly lessened the DON-stimulated intracellular reactive oxygen species and nitrogen oxidative species production. Furthermore, Sch A lowered DON-induced catalase, superoxide dismutase and glutathione peroxidase antioxidant enzyme activities but maintains glutathione S transferase activity and glutathione levels. Mechanistic studies suggest that Sch A reduced DON-induced oxidative stress by down-regulating heme oxygenase-1 expression via nuclear factor (erythroid-derived 2)-like 2 signalling pathway. In addition, Sch A decreased the DON-induced cyclooxygenase-2 expression and prostaglandin E2 production and pro-inflammatory cytokine interleukin 8 expression and secretion. This may be mediated by preventing DON-induced translocation of nuclear factor-κB, as well as activation of mitogen-activated protein kinases pathways. In the light of these findings, we concluded that Sch A exerted a cytoprotective role in DON-induced toxicity in vitro, and it would be valuable to examine in vivo effects.

Deoxynivalenol-Induced Cytotoxicity and Apoptosis in IPEC-J2 Cells Through the Activation of Autophagy by Inhibiting PI3K-AKT-mTOR Signaling Pathway

With the purpose to explore the relationship between deoxynivalenol (DON)-induced apoptosis and autophagy and provide mechanistic explanations for the toxic effects of DON on IPEC-J2 cells, we determined the cell viability, cell morphology, apoptosis, and autophagy by using autophagy inhibitor 3-methyladenine (3-MA), PI3K pathway inhibitor LY294002, and activator 740Y-P. It turned out that 3-MA was able to attenuate the reduction of cell viability induced by DON. Moreover, 3-MA was capable of upregulating the expression of DON-induced autophagic protein p62 and downregulating the expressions of DON-induced autophagic protein LC3-II and apoptotic protein Bax, suggesting that autophagy is a driving mechanism for this apoptotic induction. The results of Annexin V-FITC/PI double staining indicated that DON could induce apoptosis by inhibiting the PI3K-AKT-mTOR signaling pathway. Subsequently, it was further confirmed by Western blot analysis that DON significantly decreased expressions of P-AKT/AKT, p-mTOR/mTOR, and autophagic protein p62, and increased expression of autophagy-related protein LC3-II, suggesting that DON triggered autophagy by inhibiting the PI3K-AKT-mTOR signaling pathway. To conclude, these data reveal that DON may induce cytotoxicity and apoptosis through the activation of autophagy by suppressing the PI3K-AKT-mTOR signaling pathway. This study provides new insights into the mechanisms by which DON incurs cytotoxic effects.

Effects of Saccharomyces cerevisiae on alleviating cytotoxicity of porcine jejunal epithelia cells induced by deoxynivalenol

Deoxynivalenol (DON) is one of the mycotoxins most frequently encountering in cereal-based foods throughout the world. Saccharomyces cerevisiae was used to alleviate porcine jejunal epithelia cell (IPEC-J2) injury induced by DON in this study. The results indicated that cell viability and proliferation rates were significantly decreased when DON concentrations were increased from 0 to 64 µM after 24 h incubation (p < 0.05). The longer incubation time and higher DON concentrations would cause more serious effects on cell viability. S. cerevisiae could significantly degrade DON and decrease lactic dehydrogenase (LDH) release in the cells induced by DON (p < 0.05). DON (4 µM) could increase necrotic and apoptotic cell rates as well as decrease viable cell rates, compared with the control group (p < 0.05). However, S. cerevisiae addition in the DON group could decrease necrotic, late apoptotic and early apoptotic cell rates by 38.05%, 46.37% and 44.78% respectively, increase viable cell rates by 2.35%, compared with the single DON group (p < 0.05). In addition, S. cerevisiae addition could up-regulate mRNA abundances of IL-6, IL-8 and IL-10 in IPEC-J2 cells (p < 0.05), but down-regulate mRNA abundances of tight junction proteins (TJP-1) and occludin by 36.13% and 50.18% at 1 µM of DON (p < 0.05). It could be concluded that S. cerevisiae was able to alleviate IPEC-J2 cell damage exposed to DON.

Effects of deoxynivalenol and sodium meta-bisulphite on nutrient digestibility in growing pigs

Deoxynivalenol (DON), a mycotoxin synthesised by the Fusarium, is known to affect the growth of pigs. This effect can be attenuated with sodium meta-bisulphite (SBS). The aim of this study was to evaluate the effect of SBS with antioxidant blend on nutrient digestibility in pigs fed a diet contaminated naturally with DON. Six crossbred castrated pigs fitted surgically with single-T cannulas in the distal ileum received one of four barley-corn-soybean diets with or without SBS. After 8 d of feeding, faeces and ileal digesta were collected for 2 d. Apparent ileal digestibility (AID) of the dry matter (DM), energy, nutrients and DON, and apparent total tract digestibility (ATTD) of DM, acid detergent fibre (ADF), neutral detergent fibre (NDF), energy and DON were evaluated. The AID of phosphorus, calcium and some amino acids was increased (p < 0.05) in the DON diets whereas the ATTD of DM and energy tended to decrease (p = 0.064 and p = 0.071). SBS reduced the AID of DM, energy, ADF, ether extract, phosphorus and DON (p < 0.05) but had no effect on the ATTD of DM, energy, fibre or DON. These results show that DON improved the AID of some nutrients but tended to reduce the ATTD of energy, which could explain, although anorexia is the main effect of DON on live weight gain, the reported negative effect of DON on pig growth. Finally, SBS with antioxidant blend had reduced AID of some nutrients and intestinal absorption of DON.

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.

Nontoxic concentrations of OTA aggravate DON-induced intestinal barrier dysfunction in IPEC-J2 cells via activation of NF-κB signaling pathway

Deoxynivalenol (DON) is well-known enteropathogenic mycotoxin which can alter intestinal barrier functions. Consistently, Ochratoxin A (OTA) ingestion has been found to induce intestinal injuries, including inflammation and diarrhea. However, little is known whether OTA aggravates DON-induced toxicity. This study is designed to explore the effects of OTA on DON-induced intestinal barrier function and involved mechanism. Our results showed either DON or OTA could disrupt intestinal barrier function in a time- and dose-dependent manner, as demonstrated by decreased transepithelial electrical resistance (TEER) and increased paracellular permeability to 4 kDa dextran. However, to eliminate the involvement of cell death, nonlethal concentrations of DON and OTA were used in following experiments. The nontoxic concentration of OTA was observed to aggravate DON-induced intestinal barrier dysfunction, accompanied with tight junction disruption (Claudin-3 and Claudin-4). Moreover, nontoxic concentrations of OTA aggravated DON-induced up-regulation of pro-inflammatory cytokines expression and activated nuclear factor-κB (NF-κB) in IPEC-J2 cells. Adding NF-κB inhibitor (PDTC) alleviated the aggravating effects of nontoxic concentrations of OTA on DON-induced intestinal barrier dysfunction and inflammation. These findings indicate that nontoxic concentrations of OTA promoted DON-induced barrier dysfunction via NF-κB signaling pathway. Our experiment suggests that exposure to nontoxic concentrations of toxins also poses potentially harmful effects.

An acute challenge with a deoxynivalenol-contaminated diet has short- and long-term effects on performance and feeding behavior in finishing pigs

Mycotoxins are toxic secondary metabolites produced by various fungi and are known to contaminate animal feed ingredients especially cereals. One of the most common mycotoxins in swine diets is deoxynivalenol (DON) which is known to decrease growth performance. The objective of the present study was to evaluate the effects of single or repeated short-term DON challenges on growth performance, and feeding behavior in finishing pigs. A total of 160 pigs were distributed to four experimental groups in two successive replicates with each pig individually measured for live BW and individually fed using an electronic feeding station. The pigs in control group CC were fed with a standard finisher diet during the whole duration of the experimental period. Groups DC, CD, and DD were given the DON-contaminated diet (3.02 mg DON/kg feed) for 7 d at 113 d, at 134 d, and at 113 and 134 d of age, respectively. The DON-contaminated diet was formulated with a naturally contaminated corn. During challenge periods, ADFI was decreased by 26% to 32% (P < 0.05) and ADG by 40% to 60% (P < 0.05). The drop in ADFI during DON challenges was associated with changes in the feeding behavior: when compared to the nonchallenged pigs, pigs fed with DON-contaminated diet had lower number of meals per day (9.6 versus 8.2 meals per day on average; P < 0.05) and slower feeding rate (42.0 g/min versus 39.9 g/min on average; P < 0.05). For the whole trial period, pigs submitted to the DON challenge at the end of the experiment (i.e., first time for CD group and second time for DD group) had a lower (P < 0.05) ADFI (2.67 and 2.59 kg/d, respectively) when compared to the control CC group of pigs (2.87 kg/d). An intermediate value was reported for the DC groups (2.79 kg/d). All challenged groups, i.e., DC, CD, and DD pigs, had lower (P < 0.05) overall ADG (970, 940, and 900 g/day, respectively) than CC (1,050 g/day) for the whole trial period. Pigs challenged early in the trial, i.e., DC and DD groups, had a higher (P < 0.05) FCR than CC group (3.00 and 3.06 versus 2.80, respectively) while group CD showed intermediate results (2.92). This study demonstrates that the severity of DON toxicity in pig performance can be related to the age of exposure (113 or 134 d) and the number of exposures to the toxin (one or two). Exposure to DON also resulted to long-term effects because challenged pigs showed limited ability to recover after the DON-induced reduction of feed intake.

Deoxynivalenol inhibits the expression of trefoil factors (TFF) by intestinal human and porcine goblet cells

Trefoil factors (TFFs) are bioactive peptides expressed by several epithelia, including the intestine, where they regulate key functions such as tissue regeneration, barrier function and inflammation. Although food-associated mycotoxins, including deoxynivalenol (DON), are known to impact many intestinal functions, modulation of TFFs during mycotoxicosis has never been investigated. Here, we analyzed the effect of DON on TFFs expression using both human goblet cells (HT29-16E cells) and porcine intestinal explants. Results showed that very low doses of DON (nanomolar range) inhibit the secretion of TFFs by human goblet cells (IC₅₀ of 361, 387 and 243 nM for TFF1, 2 and 3, respectively) and prevent wound healing. RT-qPCR analysis demonstrated that the inhibitory effect of DON is related to a suppression of TFFs mRNA expression. Experiments conducted on porcine intestinal explants confirmed the results obtained on cells. Finally, the use of specific inhibitors of signal pathways demonstrated that DON-mediated suppression of TFFs expression mainly involved Protein Kinase R and the MAP kinases (MAPK) p38 and ERK1/2. Taken together, our results show for the first time that at very low doses, DON suppresses the expression and production of intestinal TFFs and alters wound healing. Given the critical role of TFFs in tissue repair, our results suggest that DON-mediated suppression of TFFs contributes to the alterations of intestinal integrity the caused by this toxin.

Effects of deoxynivalenol, 3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol on parameters associated with oxidative stress in HepG2 cells

This work studied the effect of deoxynivalenol (DON) and two of its acetylated analogs (3-ADON, 15-ADON) on first indicators of oxidative stress status, namely production of reactive oxygen species (ROS) and induction of lipid peroxidation (LPO), in HepG2 cells. HepG2 cells were exposed to different concentrations of the three toxins, either alone or in combinations, for 24, 48, and 72 h. Results of cytotoxicity obtained in HepG2 cells were correlated with the detection of ROS and LPO. This effect was inversely correlated with ROS while directly correlated with LPO for the assayed mycotoxins in individual treatment. Combinations of two toxins containing 15-ADON yielded highest values, while for two-toxin combinations with 3-ADON, the effects were minor. A combination of all three mycotoxins alleviated ROS production and the highest levels in LPO were detected, in association to a final breakdown of adaption of ROS early produced by HepG2. In conclusion, parameters of stress evaluation presented in this study (ROS and LPO), revealed increases in HepG2 cells exposed to DON, 3-ADON, and 15-ADON either individually or combined.

Protection of Porcine Intestinal-Epithelial Cells from Deoxynivalenol-Induced Damage by Resveratrol via the Nrf2 Signaling Pathway

Deoxynivalenol (DON), a common mycotoxin, usually induces oxidative stress and affects the intestinal health of humans and animals. This study investigated the protective effect of resveratrol (RES), a natural antioxidant, on alleviating the cytotoxicity induced by DON in the porcine intestinal-epithelial cell line (IPEC-J2). Cells were incubated with RES for 24 h and then exposed to DON for another 24 h. Cell viability, proliferation, apoptosis, and oxidative-stress indicators were determined. In comparison with DON-only-treated cells, pretreatment with RES (15 μM) increased the cell viability (79.74 ± 2.02 vs 90.98 ± 2.66%, P < 0.01), improved proliferation (EdU-positive cells, 26.42 ± 1.12 vs 32.05 ± 0.78%, P < 0.01), decreased accumulation of intracellular reactive oxygen species (ROS, 1.68 ± 0.05 vs 1.29 ± 0.06, P < 0.01), stabilized mitochondrial-membrane potential (MMP, 8.98 ± 1.40 vs 2.29 ± 0.76, P < 0.001), and prevented apoptosis induced by DON (13.91 ± 1.20 vs 6.83 ± 0.52%, P < 0.01). RES activated the Nrf2 signaling pathway, and transfection with Nrf2 siRNA abrogated the protection of RES against DON-induced cytotoxicity, accumulation of intracellular ROS, and mitochondria-dependent apoptosis. Collectively, RES protects IPEC-J2 cells against DON-induced damage at least partly via the Nrf2 signaling pathway.

Impact of deoxynivalenol and kaempferol on expression of tight junction proteins at different stages of Caco-2 cell proliferation and differentiation

The expression of tight junction proteins in human epithelial colorectal adenocarcinoma (Caco-2) cells was investigated after treatment by the mycotoxin of deoxynivalenol and phenolic compound of kaempferol in different stages of proliferation and differentiation.

Mycobiota and Mycotoxic Contamination of Feed Cereals

The cereals are a suitable substrate for the growth of microscopic filamentous fungi. Micromycetes are capable of reducing the nutritional value of feedstuff and they can produce several mycotoxins. The most frequent genera of microscopic filamentous fungi are Fusarium, Penicillium, Alternaria and Aspergillus. The contamination by microscopic fungi and mycotoxins was determinated in 56 samples of feed cereals originating from the Slovak Republic. The most common genera of fungi detected in the feed cereals included: Alternaria (67.8 %), Fusarium (44.6 %), Penicillium (39.2 %), Mucor (30.3 %), Rhizopus (28.5 %), Cladosporium (21.4 %), Scopulariopsis (8.9 %) and Aspergillus (1.7 %). Deoxynivalenol was present in 24 samples (42.8 %) and zearalenone in 15 samples (26.7 %). The values of both mycotoxins did not reach the regulatory limits and thus they do not pose a risk to livestock nutrition.

Occurrence and Quantitative Risk Assessment of Twelve Mycotoxins in Eggs and Chicken Tissues in China

Aflatoxins (AFs), deoxynivalenols (DONs), and zearalenones (ZENs) are common mycotoxins that contaminate feedstuff, causing contamination of poultry products. In our study, these mycotoxins were quantified in 152 egg samples collected from markets in Jiangsu (JS), Zhejiang (ZJ), and Shanghai (SH) and in 70 chicken tissue samples (liver, heart, and gizzard) from ZJ in China. The main mycotoxins observed in egg samples were DON, 15-AcDON, and ZEN, although only ZEN family mycotoxins (ZEN, α-ZEL, β-ZEL, and α-ZAL) were detected in chicken tissues. Furthermore, for the first time, we assessed the health risks of exposure of three populations (children, adults, and elder adults) to DONs (DON, 3-AcDON, and 15-AcDON) and ZEN in eggs (from three different areas) and to ZEN in chicken tissues. We show that the mean dietary intake (DI) values and the 97.5th percentile DI values of DON and ZEN through egg ingestion were lower than the provisional maximum tolerable daily intake (PMTDI) (1 μg/kg body weight (BW)/day) for the three populations in the three geographical areas studied. However, eggs contaminated with high levels of DONs and ZEN contributed to a large proportion of the PMTDI of these mycotoxins, especially in children and elder adults. Although ZEN was highly detected in the chicken tissues, no significant health risk was observed.

In silico and in vitro prediction of the toxicological effects of individual and combined mycotoxins

3-Acetyldeoxynivalenol (3-AcDON) and 15-acetyldeoxynivalenol (15-AcDON) are converted to deoxynivalenol (DON) in vivo and their simultaneous presence may increase DON intake. Mixtures of DON and its derivatives are a public health concern. In this study DON, 3-AcDON and 15-AcDON were evaluated in vitro and in silico. The in vitro cytotoxicity of DON and its derivatives individually and combined was determined by the Neutral Red (NR) assay in human hepatocarcinoma (HepG2) cells. The concentrations tested were from 1.25 to 15 μM (DON) and from 0.937 to 7.5 μM (DON derivatives). The IC₅₀ values were from >15 to 2.55 μM (DON), from 1.77 to 1.02 μM (3-AcDON), and from 4.05 to 1.68 μM (15-AcDON). 3-AcDON was the most cytotoxic molecule in HepG2 cells. The concentrations tested in combinations ranged from 0.5625 to 4.5 μM (DON), and from 0.094 to 0.75 μM (DON derivatives), with ratios of 1:6 (DON+3-AcDON and DON+15-AcDON), 1:1 (3-AcDON+15-AcDON) and 1:6:6 (DON+3-AcDON+15-AcDON). The DON+15-AcDON mixture exhibited additive effects, while the rest showed synergistic effects. In silico methods assess individual mycotoxins. Absorption, Distribution, Metabolism, Excretion and Toxicity of mycotoxins were predicted using in silico SwissADME tools. Absorption, Distribution, Metabolism and Excretion profile prediction shows high gastrointestinal absorption and CYP3A4 mediated metabolism.

Review article: Role of satiety hormones in anorexia induction by Trichothecene mycotoxins

The trichothecenes, produced by Fusarium, contaminate animal feed and human food in all stages of production and lead to a large spectrum of adverse effects for animal and human health. An hallmark of trichothecenes toxicity is the onset of emesis followed by anorexia and food intake reduction in different animal species (mink, mice and pig). The modulation of emesis and anorexia can result from a direct action of trichothecenes in the brain or from an indirect action in the gastrointestinal tract. The direct action of trichothecenes involved specific brain areas such as nucleate tractus solitarius in the brainstem and the arcuate nuclei in the hypothalamus. Activation of these areas in the brain leads to the activation of specific neuronal populations containing anorexigenic factors (POMC and CART). The indirect action of trichothecenes in the gastrointestinal tract involved, by enteroendocrine cells, the secretion of several gut hormones such as cholecystokinin (CCK) and peptide YY (PYY) but also glucagon-like peptide 1 (GLP-1), gastric inhibitory peptide (GIP) and 5-hydroxytryptamine (5-HT), which transmitted signals to the brain via the gut-brain axis. This review summarizes current knowledge on the effects of trichothecenes, especially deoxynivalenol, on emesis and anorexia and discusses the mechanisms underlying trichothecenes-induced food reduction.

Ochratoxin A, citrinin and deoxynivalenol decrease claudin-2 expression in mouse rectum CMT93-II cells

Intestinal epithelial cells are the first targets of ingested mycotoxins, such as ochratoxin A, citrinin and deoxynivalenol. It has been reported that paracellular permeability regulated by tight junctions is modulated by several mycotoxins by reducing the expression of specific claudins and integral membrane proteins in cell-cell contacts, accompanied by increase in phosphorylation of mitogen-activated protein kinases, including extracellular signal-related kinase (ERK) 1/2, p38 and c-Jun NH2-terminal protein kinase. Claudin-2 is expressed in the deep crypt cells, but not in the villus/surface cells in vivo. While Caco-2, T84 and IPEC-J2 cells, which are widely used intestinal epithelial cell lines to assess the influence of mycotoxins, do not express claudin-2, CMT93-II cells express claudin-2. We previously reported that inhibition of the ERK pathway reduced claudin-2 levels in cell-cell contacts in CMT93-II cells. In this study, we examined whether ochratoxin A, citrinin and deoxynivalenol affect claudin-2 expression and ERK1/2 phosphorylation in CMT93-II cells. We found that all mycotoxins reduced claudin-2 expression in cell-cell contacts, with reduction (by citrinin and deoxynivalenol) or no change (by ochratoxin A) in phosphorylated ERK1/2. All mycotoxins increased transepithelial electrical resistance, but did not affect flux of fluorescein. While ochratoxin A and citrinin are known to be nephrotoxic, only deoxynivalenol reduced claudin-2 expression in MDCK II cells derived from the renal tubule. These results suggest that claudin-2 expression is regulated not only by the ERK pathway, but also by other pathways in an organ-specific manner.