Mycotoxicoses in Veterinary Medicine: Fusarium Toxins, Grass Staggers, and Neothyphodium Toxins.

Fungi are a large group of eukaryotic microorganisms that can readily adapt to diverse environments and occur in almost all climatic zones and continents. Although some fungi are inevitable in the environment for the decay and recycling of organic material, many species are known to produce secondary metabolites, and these mycotoxins, when ingested with food or feed materials, can adversely affect animal and human health. Among the toxigenic fungi, Fusarium species are recognized as so-called field fungi, invading crops and producing mycotoxins predominantly before harvest. Fusarium produces a wide array of mycotoxins, causing different plant diseases. Fusariosis causes significant economic losses in a wide range of crops. Fusarium secondary metabolites, particularly trichothecenes, are potent toxins in mammalian species and cause diverse adverse effects in humans and animals. Other prominent Fusarium toxins with entirely different chemical structures are zearalenone and its derivatives and fumonisins. With an entirely different life cycle, toxins of endophytes belonging to the genus Epichloë and Neothyphodium coenophialum and Neothyphodium lolii comprise an animal health risk, particularly for grazing animals. This review aimed to summarize the adverse effects of selected Fusarium and Epichloë toxins, with a special emphasis on their occurrence in roughages and their mechanisms of action, and describe their effect on animal health and welfare and the potentially related public health risks.

Individual cytotoxicity of three major type A trichothecene, T-2, HT-2, and diacetoxyscirpenol in human Jurkat T cells.

Mycotoxins are toxic, fungal secondary metabolites that contaminate agricultural commodities, food, and feed. Among them, T-2, HT-2, and diacetoxyscirpenol (DAS; the major type A trichothecene) are primarily produced from Fusarium species. These mycotoxins exert numerous toxicological effects in animals and humans, such as dermatotoxicity, haematotoxicity, hepatotoxicity, nephrotoxicity, neurotoxicity, and immunotoxicity. In the present study, human Jurkat T cells were used as a model to investigate apoptotic cell death induced by T-2, HT-2, and DAS. The results showed that T-2, HT-2, and DAS decreased cell viability and increased production of Reactive Oxygen Species in a time- and dose-dependency. Based on their IC50 values, they could be ranked in decreasing order of cytotoxicity as T-2 > HT-2 > DAS. All tested mycotoxins caused DNA fragmentation, up-regulated cytochrome C, caspase 3, and caspase 9 mRNA levels, and down-regulated the relative expression of Bcl-2 and caspase 8. The effects of these trichothecenes on apoptosis were determined based on flow cytometry. At the IC50 concentrations, the percentages of apoptotic cells were significantly higher than for the controls. Taken together, these data suggested that T-2, HT-2, and DAS could induce apoptosis through the mitochondrial apoptotic pathway.

Storage Fungi and Mycotoxins Associated with Rice Samples Commercialized in Thailand.

The study focused on the examination of the different fungal species isolated from commercial rice samples, applying conventional culture techniques, as well as different molecular and phylogenic analyses to confirm phenotypic identification. Additionally, the mycotoxin production and contamination were analyzed using validated liquid chromatography-tandem mass spectrometry (LC-MS/MS). In total, 40 rice samples were obtained covering rice berry, red jasmine rice, brown rice, germinated brown rice, and white rice. The blotting paper technique applied on the 5 different types of rice samples detected 4285 seed-borne fungal infections (26.8%) for 16,000 rice grains. Gross morphological data revealed that 19 fungal isolates belonged to the genera Penicillium/Talaromyces (18 of 90 isolates; 20%) and Aspergillus (72 of 90 isolates; 80%). To check their morphologies, molecular data (fungal sequence-based BLAST results and a phylogenetic tree of the combined ITS, BenA, CaM, and RPB2 datasets) confirmed the initial classification. The phylogenic analysis revealed that eight isolates belonged to P. citrinum and, additionally, one isolate each belonged to P. chermesinum, A. niger, A. fumigatus, and A. tubingensis. Furthermore, four isolates of T. pinophilus and one isolate of each taxon were identified as Talaromyces (T. radicus, T. purpureogenum, and T. islandicus). The results showed that A. niger and T. pinophilus were two commonly occurring fungal species in rice samples. After subculturing, ochratoxin A (OTA), generated by T. pinophilus code W3-04, was discovered using LC-MS/MS. In addition, the Fusarium toxin beauvericin was detected in one of the samples. Aflatoxin B1 or other mycotoxins, such as citrinin, trichothecenes, and fumonisins, were detected. These preliminary findings should provide valuable guidance for hazard analysis critical control point concepts used by commercial food suppliers, including the analysis of multiple mycotoxins. Based on the current findings, mycotoxin analyses should focus on A. niger toxins, including OTA and metabolites of T. pinophilus (recently considered a producer of emerging mycotoxins) to exclude health hazards related to the traditionally high consumption of rice by Thai people.

Zearalenone and its metabolite exposure directs oestrogen metabolism towards potentially carcinogenic metabolites in human breast cancer MCF-7 cells.

Zearalenone (ZEN) is produced by Fusarium species contaminating various agriculture crops. In this study, the effects of ZEN and its metabolites α-zearalenol (α-ZEL), and ß-zearalenol (ß-ZEL) on the formation of carcinogenic oestrogen-catechols in MCF-7 cells were investigated. To assess the effects of mycoestrogens on the activity of cytochrome P450 1A1 and CYP1B1, the rate of ethoxyresorufin O-deethylation (EROD-assay) was measured. The effects of mycoestrogens on the expression of CYP 1A1, CYP 1B1, aryl-hydrocarbon receptor (AhR), and oestrogen receptor alpha (ERα) were determined by qPCR. The catechol-O-methyltransferase (COMT) activity was measured as the ratio of the methoxy metabolites of oestradiol. Results show that mycoestrogens inhibited significantly the CYP1-dependent EROD activities. In the presence of selective inhibitors, mycoestrogens reduced CYP 1A1 and enhanced CYP 1B1 activity. Quantitative PCR analyses demonstrated the upregulation of AhR and confirmed the selective effect of mycoestrogens on CYP1 expression levels and the decline of the CYP 1A1/CYP 1B1 ratio. Mycoestrogens increased the ratio of 4-MeOE to 2-MeOE2 formation significantly (P < 0.05). Our results suggest that the tested mycoestrogens increase the production of CYP1B1-mediated oestrogen catechol metabolites, directing the biotransformation of E2 towards 4-OHE2, which has been identified earlier as a crucial factor in oestrogen-induced tumour initiation.

Epithelial integrity, junctional complexes, and biomarkers associated with intestinal functions.

An intact intestinal barrier is crucial for immune homeostasis and its impairment activates the immune system and may result in chronic inflammation. The epithelial cells of the intestinal barrier are connected by tight junctions, which form an anastomosing network sealing adjacent epithelial cells. Tight junctions are composed of transmembrane and cytoplasmic scaffolding proteins. Transmembrane tight junction proteins at the apical-lateral membrane of the cell consist of occludin, claudins, junctional adhesion molecules, and tricellulin. Cytoplasmic scaffolding proteins, including zonula occludens, cingulin and afadin, provide a direct link between transmembrane tight junction proteins and the intracellular cytoskeleton. Each individual component of the tight junction network closely interacts with each other to form an efficient intestinal barrier. This review aims to describe the molecular structure of intestinal epithelial tight junction proteins and to characterize their organization and interaction. Moreover, clinically important biomarkers associated with impairment of gastrointestinal integrity are discussed.

Mitigation of sterigmatocystin exposure in cattle by difructose anhydride III feed supplementation and detection of urinary sterigmatocystin and serum amyloid A concentrations.

We evaluated the effects of supplementing cattle feed with difructose anhydride III (DFA III) by measuring urinary sterigmatocystin (STC) concentrations using 20 Japanese Black cattle aged 9-10 months from one herd. DFA III was supplemented for 2 weeks for 10 animals, and non-treated animals served as controls. The natural STC concentration in the dietary feed was 0.06  mg kg - 1 (mixture of roughage and concentrate) at the beginning of the study (Day 0). The urine STC concentration was measured using liquid chromatography with tandem mass spectrometry 1 d prior to DFA III administration, 9 and 14 d thereafter, and 9 d following supplementation cessation, concomitant with the measurement of serum amyloid A (SAA). The number of heifers in which STC was detected in the urine was low (10 %) in the DFA III group compared to that (60 %) in the control group on Day 9. After 9 d following supplementation cessation (Day 23), STC concentrations were significantly lower ( P = 0.032 ) in the DFA III group than in the control group, although there was no difference in the number of heifers in which urinary STC was detected or in SAA concentrations between the two groups. Our findings demonstrate the effect of DFA III on reducing the urinary concentration of STC in Japanese Black cattle.

An overview of aflatoxin B1 biotransformation and aflatoxin M1 secretion in lactating dairy cows.

Milk is considered a perfect natural food for humans and animals. However, aflatoxin B1 (AFB1) contaminating the feeds fed to lactating dairy cows can introduce aflatoxin M1 (AFM1), the main toxic metabolite of aflatoxins into the milk, consequently posing a risk to human health. As a result of AFM1 monitoring in raw milk worldwide, it is evident that high AFM1 concentrations exist in raw milk in many countries. Thus, the incidence of AFM1 in milk from dairy cows should not be underestimated. To further optimize the intervention strategies, it is necessary to better understand the metabolism of AFB1 and its biotransformation into AFM1 and the specific secretion pathways in lactating dairy cows. The metabolism of AFB1 and its biotransformation into AFM1 in lactating dairy cows are drawn in this review. Furthermore, recent data provide evidence that in the mammary tissue of lactating dairy cows, aflatoxins significantly increase the activity of a protein, ATP-binding cassette super-family G member 2 (ABCG2), an efflux transporter known to facilitate the excretion of various xenobiotics and veterinary drugs into milk. Further research should focus on identifying and understanding the factors that affect the expression of ABCG2 in the mammary gland of cows.

Mycotoxicoses in veterinary medicine: Aspergillosis and penicilliosis.

Molds and mycotoxins are contaminants of animal feed causing spoilage and clinical intoxication. Animal exposure to mycotoxins reflects diet composition with major differences occurring between animals kept predominantly of pastures, i.e. ruminants and horses, and those consuming formulated feed like pigs and poultry. Mixed feeds are composed of several ingredients, often sourced from different continents. Subsequently, practitioners may confront endemic diseases and signs of toxin exposure related to toxins imported accidentally with contaminated feed materials from other countries and continents. Mycotoxins comprise more than 300 to 400 different chemicals causing a variety of clinical symptoms. Mycotoxin exposure causes major economic losses due to reduced performance, impaired feed conversion and fertility, and increased susceptibility to environmental stress and infectious diseases. In acute cases, clinical symptoms following mycotoxin ingestion are often non-specific, hindering an immediate diagnosis. Furthermore, most mold species produce more than one toxin, and feed commodities are regularly contaminated with various mold species resulting in complex mixtures of toxins in formulated feeds. The effects of these different toxins may be additive, depending on the level and time of exposure, and the intensity of the clinical symptoms based on age, health, and nutritional status of the exposed animal(s). Threshold levels of toxicity are difficult to define and discrepancies between analytical data and clinical symptoms are common in daily practice. This review aims to provide an overview of Aspergillus and Penicillium toxins that are frequently found in feed commodities and discusses their effects on animal health and productivity.

Beyond Heat Stress: Intestinal Integrity Disruption and Mechanism-Based Intervention Strategies.

The current climate changes have increased the prevalence and intensity of heat stress (HS) conditions. One of the initial consequences of HS is the impairment of the intestinal epithelial barrier integrity due to hyperthermia and hypoxia following blood repartition, which often results in a leaky gut followed by penetration and transfer of luminal antigens, endotoxins, and pathogenic bacteria. Under extreme conditions, HS may culminate in the onset of "heat stroke", a potential lethal condition if remaining untreated. HS-induced alterations of the gastrointestinal epithelium, which is associated with a leaky gut, are due to cellular oxidative stress, disruption of intestinal integrity, and increased production of pro-inflammatory cytokines. This review summarizes the possible resilience mechanisms based on in vitro and in vivo data and the potential interventions with a group of nutritional supplements, which may increase the resilience to HS-induced intestinal integrity disruption and maintain intestinal homeostasis.

Effects of a feed additive blend on broilers challenged with heat stress.

We evaluated a blend of medium-chain fatty acids (MCFA), organic acids, and a polyphenol antioxidant on gut integrity. Eighty Ross Broilers were exposed to 20-22°C (control - normothermic) or to 35-39.5°C (heat stress) for eight hours a day for a period of 1 or 5 days. Birds were fed a standard diet, or a diet supplemented with the test blend. Thereafter, birds were euthanized, and intestinal sections were excised for morphological, morphometric and gene expression analyses. Blood samples were collected for glucose-6-phosphate dehydrogenase (G6PD), glutathione peroxidase (GSH-Px) activity and trolox equivalent antioxidant capacity (TEAC) determination. Heart and liver tissues were used to quantify the expression of heat shock proteins 60 and 70 (HSP60 and HSP70, respectively) and inhibitor of kappa light chain gene enhancer in B cells alpha (IKBA). The jejunum was the most sensitive intestinal section, where heat stress modulated the expression of HSP70, of the inflammatory markers IKBA, interleukin 8 (IL-8), interferon gamma (IFNγ), and toll-like receptor 4 (TLR4). Moreover, expression of tight junctions (CLDN1, ZO1 and ZO2) and nutrient transporters (PEPT1 and EAAT3) was modulated especially in the jejunum. In conclusion, the feed additive blend protected intestines during heat stress from the decrease in villus height and crypt depth, and from the increase in villus width. Especially in the jejunum, heat stress played an important role by modulating oxidative stress and inflammation, impairing gut integrity and nutrient transport, and such deleterious effects were alleviated by the feed additive blend. RESEARCH HIGHLIGHTS Jejunum is the most sensitive intestinal segment during heat stress. Heat stress affects the expression of tight junctions and nutrient transporters. Feed management helps to alleviate the disturbances caused by heat stress. A blend of MCFA, organic acids and a polyphenol protects broilers under heat stress.

l-Arginine supplementation prevents intestinal epithelial barrier breakdown under heat stress conditions by promoting nitric oxide synthesis.

Heat stress (HS) induced by exposure to high ambient temperatures or prolonged excessive physical activities is known to primarily induce deleterious effects on the intestinal integrity by disrupting junctional complexes. Considering the association of l-arginine (l-Arg) with the improvement of gut function, the hypothesis of this study was to assess whether l-Arg supplementation can prevent the intestinal barrier disruption under HS conditions and to understand whether the l-Arg-induced effects are associated with maintaining nitric oxide (NO) as the major product of l-Arg metabolism. For this study, human colorectal adenocarcinoma (Caco-2) cells grown on Transwell inserts were pretreated with different l-Arg concentrations (0.4, 1, and 4 mmol/L), and after exposure to HS, markers of intestinal barrier integrity, stress-related markers, and NO levels were determined. l-Arg deprivation markedly increased the mRNA expression of heat shock protein 70 and heme-oxygenase-1 under HS conditions. The HS-induced drop in transepithelial electrical resistance values and increase in Lucifer Yellow permeability could be prevented by 4 mmol/L l-Arg supplementation. In turn, l-Arg mitigated the downregulation and delocalization of adherens junction protein E-cadherin in HS-exposed cells. NO and inducible NO synthase levels were significantly decreased in HS-exposed cells, whereas pretreatment with 4 mmol/L l-Arg prevented this decrease. Inhibition of inducible NO synthase by the NO synthase inhibitor l-NG-nitroarginine methyl ester abrogated the effect of l-Arg on preserving intestinal integrity under HS conditions as measured by transepithelial electrical resistance, Lucifer Yellow flux, and E-cadherin expression. In summary, l-Arg supplementation protects the intestinal epithelial integrity, at least partly, by maintaining NO synthesis under HS conditions.

Population variability in animal health: Influence on dose-exposure-response relationships: Part I: Drug metabolism and transporter systems.

There is an increasing effort to understand the many sources of population variability that can influence drug absorption, metabolism, disposition, and clearance in veterinary species. This growing interest reflects the recognition that this diversity can influence dose-exposure-response relationships and can affect the drug residues present in the edible tissues of food-producing animals. To appreciate the pharmacokinetic diversity that may exist across a population of potential drug product recipients, both endogenous and exogenous variables need to be considered. The American Academy of Veterinary Pharmacology and Therapeutics hosted a 1-day session during the 2017 Biennial meeting to explore the sources of population variability recognized to impact veterinary medicine. The following review highlights the information shared during that session. In Part I of this workshop report, we consider sources of population variability associated with drug metabolism and membrane transport. Part II of this report highlights the use of modeling and simulation to support an appreciation of the variability in dose-exposure-response relationships.

Fructo-Oligosaccharide (DFA III) Feed Supplementation for Mitigation of Mycotoxin Exposure in Cattle-Clinical Evaluation by a Urinary Zearalenone Monitoring System.

The potential effect of difructose anhydride III (DFA III) supplementation in cattle feed was evaluated using a previously developed urinary-zearalenone (ZEN) monitoring system. Japanese Black cattle from two beef herds aged 9⁻10 months were used. DFA III was supplemented for two weeks. ZEN concentrations in feed were similar in both herds (0.27 and 0.22 mg/kg in roughage and concentrates, respectively), and below the maximum allowance in Japan. ZEN, α-zearalenol (α-ZOL), and ß-ZOL concentrations in urine were measured using LC/MS/MS the day before DFA III administration, 9 and 14 days thereafter, and 9 days after supplementation ceased. Significant differences in ZEN, α-ZOL, ß-ZOL, and total ZEN were recorded on different sampling dates. The concentration of inorganic phosphate in DFA III-supplemented animals was significantly higher than in controls on day 23 (8.4 vs. 7.7 mg/dL), suggesting a possible role of DFA III in tight junction of intestinal epithelial cells. This is the first evidence that DFA III reduces mycotoxin levels reaching the systemic circulation and excreted in urine. This preventive effect may involve an improved tight-junction-dependent intestinal barrier function. Additionally, our practical approach confirmed that monitoring of urinary mycotoxin is useful for evaluating the effects of dietary supplements to prevent mycotoxin adsorption.

α-Lipoic acid prevents the intestinal epithelial monolayer damage under heat stress conditions: model experiments in Caco-2 cells.

PURPOSE: Under conditions of high ambient temperatures and/or strenuous exercise, humans and animals experience considerable heat stress (HS) leading among others to intestinal epithelial damage through induction of cellular oxidative stress. The aim of this study was to characterize the effects of α-Lipoic Acid (ALA) on HS-induced intestinal epithelial injury using an in vitro Caco-2 cell model. METHODS: A confluent monolayer of Caco-2 cells was pre-incubated with ALA (24 h) prior to control (37 °C) or HS conditions (42 °C) for 6 or 24 h and the expression of heat shock protein 70 (HSP70), heat shock factor-1 (HSF1), and the antioxidant Nrf2 were investigated. Intestinal integrity was determined by measuring transepithelial resistance, paracellular permeability, junctional complex reassembly, and E-cadherin expression and localization. Furthermore, cell proliferation was measured in an epithelial wound healing assay and the expression of the inflammatory markers cyclooxygenase-2 (COX-2) and transforming growth Factor-ß (TGF-ß) was evaluated. RESULTS: ALA pretreatment increased the HSP70 mRNA and protein expression under HS conditions, but did not significantly modulate the HS-induced activation of HSF1. The HS-induced increase in Nrf2 gene expression as well as the Nrf2 nuclear translocation was impeded by ALA. Moreover, ALA prevented the HS-induced impairment of intestinal integrity. Cell proliferation under HS conditions was improved by ALA supplementation as demonstrated in an epithelial wound healing assay and ALA was able to affect the HS-induced inflammatory response by decreasing the COX-2 and TGF-ß mRNA expression. CONCLUSIONS: ALA supplementation could prevent the disruption of intestinal epithelial integrity by enhancing epithelial cell proliferation, and reducing the inflammatory response under HS conditions in an in vitro Caco-2 cell model.

Zearalenone (ZEN) disrupts the anti-inflammatory response of bovine oviductal epithelial cells to sperm in vitro.

Dietary contamination by Zearalenone (ZEN) has a detrimental effect on bovine fertility. Recently, we showed a novel anti-inflammatory response of bovine oviductal epithelial cells (BOEC) to active sperm cells in vitro. The aim of the present study was to investigate the effect of ZEN exposure of BOEC on the immune-related cytokine expression in response to bovine sperm. At concentrations of 100 and 1000ng/mL, ZEN induced the expression of TNF and IL1B (pro-inflammatory cytokines) as well as IL8 (chemokine) in BOEC in a dose-dependent manner. Furthermore, ZEN induced PTGES expression and PGE2 secretion in BOEC. Sperm co-culture induced an anti-inflammatory response in BOEC with upregulation of TGFB, secretion of PGE2 and downregulation of TNF. Most importantly, ZEN at 1-1000ng/mL eliminated the response of BOEC to sperm. Estradiol-17ß (5ng/mL) treatment did not produce the same effects as ZEN, suggesting that the response of BOEC to ZEN is, at least in part, not mediated by estrogen receptors. Taken together, ZEN can produce inflammatory effects on BOEC by stimulating the expressions of pro-inflammatory cytokines and disrupt the normal interaction between sperm and BOEC at the level of cytokine expressions and PGE2 production. Thus, exposure of the bovine oviduct to ZEN may negatively affect sperm survival and reduce fertility.

Gas Chromatography-Mass Spectrometry for Metabolite Profiling of Japanese Black Cattle Naturally Contaminated with Zearalenone and Sterigmatocystin.

The objective of this study was to evaluate the metabolic profile of cattle fed with or without zearalenone (ZEN) and sterigmatocystin (STC)-contaminated diets using a gas chromatography-mass spectrometry metabolomics approach. Urinary samples were collected from individual animals (n = 6 per herd) from fattening female Japanese Black (JB) cattle herds (23 months old, 550-600 kg). Herd 1 had persistently high urinary ZEN and STC concentrations due to the presence of contaminated rice straw. Herd 2, the second female JB fattening herd (23 months old, 550-600 kg), received the same dietary feed as Herd 1, with non-contaminated rice straw. Urine samples were collected from Herd 1, two weeks after the contaminated rice straw was replaced with uncontaminated rice straw (Herd 1N). Identified metabolites were subjected to principal component analysis (PCA) and ANOVA. The PCA revealed that the effects on cattle metabolites depended on ZEN and STC concentrations. The contamination of cattle feed with multiple mycotoxins may alter systemic metabolic processes, including metabolites associated with ATP generation, amino acids, glycine-conjugates, organic acids, and purine bases. The results obtained from Herd 1N indicate that a two-week remedy period was not sufficient to improve the levels of urinary metabolites, suggesting that chronic contamination with mycotoxins may have long-term harmful effects on the systemic metabolism of cattle.

Characterizing microbiota-independent effects of oligosaccharides on intestinal epithelial cells: insight into the role of structure and size : Structure-activity relationships of non-digestible oligosaccharides.

PURPOSE: The direct effects of galacto-oligosaccharides (GOS), including Vivinal® GOS syrup (VGOS) and purified Vivinal® GOS (PGOS), on the epithelial integrity and corresponding interleukin-8 (IL-8/CXCL8) release were examined in a Caco-2 cell model for intestinal barrier dysfunction. To investigate structure-activity relationships, the effects of individual DP fractions of VGOS were evaluated. Moreover, the obtained results with GOS were compared with Caco-2 monolayers incubated with fructo-oligosaccharides (FOS) and inulin. METHODS: Caco-2 monolayers were pretreated (24 h) with or without specific oligosaccharides or DP fractions of VGOS (DP2 to DP6) before being exposed for 12 or 24 h to the fungal toxin deoxynivalenol (DON). Transepithelial electrical resistance and lucifer yellow permeability were measured to investigate barrier integrity. A calcium switch assay was used to study the reassembly of tight junction proteins. Release of CXCL8, a typical marker for inflammation, was quantified by ELISA. RESULTS: In comparison with PGOS, FOS and inulin, VGOS showed the most pronounced protective effect on the DON-induced impairment of the monolayer integrity, acceleration of the tight junction reassembly and the subsequent CXCL8 release. DP2 and DP3 in concentrations occurring in VGOS prevented the DON-induced epithelial barrier disruption, which could be related to their high prevalence in VGOS. However, no effects of the separate DP GOS fractions were observed on CXCL8 release. CONCLUSIONS: This comparative study demonstrates the direct, microbiota-independent effects of oligosaccharides on the intestinal barrier function and shows the differences between individual galacto- and fructo-oligosaccharides. This microbiota-independent effect of oligosaccharides depends on the oligosaccharide structure, DP length and concentration.

The intestinal barrier as an emerging target in the toxicological assessment of mycotoxins.

Mycotoxins, the secondary metabolites of fungal species, are the most frequently occurring natural food contaminants in human and animal diets. Risk assessment of mycotoxins focused as yet on their mutagenic, genotoxic and potential carcinogenic effects. Recently, there is an increasing awareness of the adverse effects of various mycotoxins on vulnerable structures in the intestines. In particular, an impairment of the barrier function of the epithelial lining cells and the sealing tight junction proteins has been noted, as this could result in an increased translocation of luminal antigens and pathogens and an excessive activation of the immune system. The current review aims to provide a summary of the available evidence regarding direct effects of various mycotoxins on the intestinal epithelial barrier. Available data, based on different cellular and animal studies, show that food-associated exposure to certain mycotoxins, especially trichothecenes and patulin, affects the intestinal barrier integrity and can result in an increased translocation of harmful stressors. It is therefore hypothesized that human exposure to certain mycotoxins, particularly deoxynivalenol, as the major trichothecene, may play an important role in etiology of various chronic intestinal inflammatory diseases, such as inflammatory bowel disease, and in the prevalence of food allergies, particularly in children.

Deoxynivalenol and Its Modified Forms: Are There Major Differences?

Considering the diverse toxic effects of the Fusarium toxin deoxynivalenol (DON), its common occurrence in wheat-based products, and its stability during processing, DON constitutes an increasing health concern for humans and animals. In addition to the parent compound DON, human and animal exposure encompasses the acetylated fungal metabolites 3-acetyl-deoxynivalenol (3ADON) and 15-acetyl-deoxynivalenol (15ADON) as well as the plant-derived DON-glucoside (DON3G) and the bacterial product de-epoxy-DON (DOM-1). In the current study we used the well-established Caco-2 cell model to compare the effects of these naturally occurring forms of DON on cell viability and markers of barrier integrity, as well as on the release of the pro-inflammatory chemokine chemokine CXC motif ligand (CXCL8). Results show that 3ADON is less potent in inducing adverse effects on barrier integrity when compared to DON, whereas 15ADON appears to be slightly more potent than DON. In contrast, DON3G and DOM-1 exerted no measurable adverse effects on the intestinal barrier. It was also demonstrated that galacto-oligosaccharides (GOS) are able to protect epithelial cells against DON and its acetylated forms, which suggests that GOS are beneficial food additives in the protection of vulnerable segments of the human population against adverse effects of DON and its derivatives.

Enrofloxacin and Probiotic Lactobacilli Influence PepT1 and LEAP-2 mRNA Expression in Poultry.

Expression of peptide transporter 1 (PepT1) and liver-expressed antimicrobial peptide 2 (LEAP-2) in chickens can be influenced by food deprivation, pathological conditions and drug administration. Effect of three putative probiotic Lactobacillus strains and enrofloxacin on the expression of PepT1 and LEAP-2 mRNA was investigated in Ross 308 chickens. One-day-old chicks (n = 24) were allocated to following groups: control (without treatment); group treated with probiotics via feed; group treated with a combination of probiotics and enrofloxacin; and a group given enrofloxacin only. The drug was administered at a dose of 10 mg kg-1, via drinking water for 5 days. Samples from liver, duodenum and jejunum were collected 126 h after the start of the treatment. Expression levels of PepT1 and LEAP-2 were determined by real-time polymerase chain reaction and were statistically evaluated by Mann-Whitney test. Enrofloxacin administered alone or in combination with probiotics provoked a statistically significant up-regulation of PepT1 mRNA levels in the measured organ sites. These changes can be attributed to a tendency of improvement in utilization of dietary peptide and in body weight gain. LEAP-2 mRNA expression levels did not change significantly in enrofloxacin-treated chickens in comparison with control group.