Dietary Deoxynivalenol Research Articles

Metabolism of the masked mycotoxin deoxynivalenol-3-glucoside in rats

Deoxynivalenol-3-β-d-glucoside (D3G), a plant metabolite of the Fusarium mycotoxin deoxynivalenol (DON), might be hydrolyzed in the digestive tract of mammals, thus contributing to the total dietary DON exposure of individuals. Yet, D3G has not been considered in regulatory limits set for DON for foodstuffs due to the lack of in vivo data. The aim of our study was to evaluate whether D3G is reactivated in vivo by investigation of its metabolism in rats. Six Sprague-Dawley rats received water, DON (2.0mg/kg body weight (b.w.)) and the equimolar amount of D3G (3.1mg/kg b.w.) by gavage on day 1, 8 and 15, respectively. Urine and feces were collected for 48h and analyzed for D3G, DON, deoxynivalenol-glucuronide (DON-GlcA) and de-epoxy deoxynivalenol (DOM-1) by a validated LC–tandem mass spectrometry (MS/MS) based biomarker method. After administration of D3G, only 3.7±0.7% of the given dose were found in urine in the form of analyzed analytes, compared to 14.9±5.0% after administration of DON, and only 0.3±0.1% were detected in the form of urinary D3G. The majority of administered D3G was recovered as DON and DOM-1 in feces. These results suggest that D3G is little bioavailable, hydrolyzed to DON during digestion, and partially converted to DOM-1 and DON-GlcA prior to excretion. Our data indicate that D3G is of considerably lower toxicological relevance than DON, at least in rats.

Synthesis of deoxynivalenol-3-ß-D-O-glucuronide for its use as biomarker for dietary deoxynivalenol exposure

Trichothecene mycotoxins are prevalent toxic secondary metabolic products of several fungal species and pose a serious threat to human and animal health. Deoxynivalenol (DON) is known to undergo rapid metabolisation after uptake. The formed glucuronides are urinary excreted and could therefore serve as possible biomarkers for daily uptake measurement. So far human exposure to the major toxin DON was estimated from dietary average intake or by measurement of the parent toxin after hydrolysis. These approaches are indirect and time-consuming. Due to the clear demand for a direct determination method and lack of an available reference substance we synthesised DON-3-O-ö-D-glucuronide. The Königs-Knorr procedure using acetobromo-α-D-glucuronic acid methyl ester as glucuronyl-donor was optimised to produce the target compound in mg scale allowing subsequent characterisation via nuclear magnetic resonance and LC-MS/MS.

Deoxynivalenol as a contaminant of broiler feed: Intestinal development, absorptive functionality, and metabolism of the mycotoxin

Deoxynivalenol (DON) has been recently documented to deteriorate intestinal morphology in chickens at dietary doses that are regarded as safe for this species. The present trial was conducted to explore the significance of these morphological changes in relation to intestinal absorptive functionality and DON metabolism. Ross broilers at 7 d of age were fed either a basal diet (0.265 ± 0.048 mg of DON/kg; 0.013 ± 0.001 mg of zearalenone/kg), a low DON diet (1.68 mg of DON/kg; 0.145 ± 0.007 mg of zearalenone/kg), or a high DON diet (12.209 ± 1.149 mg of DON/kg; 1.094 ± 0.244 mg of zearalenone/kg). The DON diets (to variable degrees) progressively decreased the relative density (weight:length) of the small intestine with increasing exposure length, which could be correlated with a decrease in villus height in the small intestine. Short circuit current of the jejunal epithelium, reflecting transport function of the epithelium per unit area, was reduced (P = 0.001) in the birds fed the high DON diet. The increasing dietary level of DON linearly (P = 0.035) increased the length of the jejunum in wk 4 of exposure, resulting in conservation of macronutrient retention. Upon challenging the birds with a fixed amount of DON after wk 5 of exposure, higher (P ≤ 0.033) amounts of DON and the detoxification metabolite (de-epoxy-DON) were found at 5 h postchallenge in the guts of birds raised on the DON diets. The increasing level of previous exposure to DON linearly (P = 0.040) decreased the plasma level of DON in the birds at 1 h postchallenge. The amounts of zearalenone and its analogs in the gut and plasma also followed a trend similar to that for DON. These data suggest that intestines in chickens may adapt to a chronic DON challenge by morphological and functional modifications. The birds having previous exposure to Fusarium mycotoxins showed moderate detoxification coupled with reduced transfer of the mycotoxins to systemic circulation. Some metabolites of zearalenone found in this study were previously unknown for chickens.

Deoxynivalenol as a contaminant of broiler feed: Effects on bird performance and response to common vaccines

Recent data suggest that Fusarium trichothecenes may reduce broiler performance at levels previously thought not to affect this variable in chickens. In the present study, we investigated the effects of deoxynivalenol (DON), a type-B trichothecene, on broilers. Male broilers at 7 d of age were fed either a basal diet (0.265 ± 0.048 mg of DON; 0.013 ± 0.001 mg of zearalenone/kg), a low DON diet (1.68 mg of DON/kg; 0.145 ± 0.007 mg of zearalenone/kg), or a high DON diet (12.209 ± 1.149 mg of DON/kg; 1.094 ± 0.244 mg of zearalenone/kg). Increasing levels of DON decreased the weekly weight gain linearly (P ≤ 0.041) during the first 3 wk of exposure; there were no significant differences in the weight gain of the birds after wk 3. With increasing levels of DON, the titers against Newcastle disease virus increased linearly during wk 2 (P = 0.022) and wk 4 (P = 0.033) of exposure, whereas the titers against infectious bronchitis virus decreased linearly (P = 0.006) during wk 5 of exposure. The serum protein concentration increased linearly (P = 0.017) during wk 2 and quadratically (P = 0.002) during wk 4 of exposure. Under these experimental conditions, the performance and vaccine response of the broilers were modulated to varying degrees at concentrations of DON that are currently permitted (up to 5 mg/kg of diet) in many countries. Further studies are therefore required to clarify the implications of these results on the welfare of chickens.

Effects of increasing dietary concentrations of corn naturally contaminated with deoxynivalenol on broiler and turkey poult performance and response to lipopolysaccharide

In this study, 2 experiments determined the effects of increasing dietary concentrations of deoxynivalenol (DON) on performance, intestinal morphology, and measures of innate immunity in broilers and turkeys. For experiment 1, the 3-wk study used 5 concentrations of DON (up to 18 or 10 mg of DON/kg of feed in broilers or turkeys, respectively) from naturally contaminated corn. The BW gains were cubically or quadratically affected by the increasing dietary concentrations of DON for broilers and turkeys, respectively; however, feed consumption was not affected. For experiment 2, the birds were subsequently injected or not injected with lipopolysaccharide (LPS) 24 h before tissue and blood sample collection. Dietary DON had no effect on intestinal crypt depth, but linearly increased the mid-ileal villus height in broilers (P = 0.04). An interaction was observed between the LPS challenge and the dietary DON with regards to heterophil to lymphocyte ratio (P < 0.05) in broilers, but not in turkeys. The cecal tonsil cell phagocytosis of microbeads was not affected by the dietary concentration of DON either with or without the subsequent LPS challenge for both broilers and turkeys. Conversely, the phagocytic capacity of cecal tonsil cells to engulf killed Staphylococcus aureus was significantly reduced (over 2.5-fold) when broilers were fed the highest concentration of dietary DON (non-LPS-challenged; P < 0.05). However, diets containing DON showed no effects on broilers when they were challenged with LPS. Antibody-dependent phagocytosis (S. aureus) was not affected in turkeys fed DON. Overall, corn naturally contaminated with up to 18 or 10 mg/kg of DON (broiler or turkey, respectively) reduced bird BW gain at 21 d of age, reduced antibody-dependent phagocytosis of previously killed S. aureus by cecal tonsil cells in non-LPS-challenged broilers, and greatly decreased heterophil to lymphocyte ratios in LPS-challenged broilers.

Expression of immune relevant genes in pigs under the influence of low doses of deoxynivalenol (DON)

Deoxynivalenol (DON) is one of the most common Fusarium toxins in animal feed and poses a potential risk especially for monogastric animals like pigs. DON is known to modulate the immune system, dependent on dose and frequency of exposure. The aim of the study was to investigate the effects of chronic exposure to low levels of DON on the expression of immune relevant genes. In a feeding trial (84days), 20 pigs were assigned equally to a control and a treatment group. The DON-content of the contaminated diet was 1.2mg/kg from day 1 to 41, from day 42 it was elevated to 2.0mg/kg. The control group (n = 10) was fed a diet with a DON concentration lower than 0.05mg/kg. Blood samples were taken over the course of the study and ileum samples were taken at slaughter. Gene expression measurement was done using real-time RT-qPCR. For target genes, those cytokines were chosen, which were estimated to be implicated in the modulation of the immune system induced by DON ingestion. In ileum, significant down-regulations could be observed for IL-1β and IL-8 (p < 0.05). Most significant regulations in blood could be detected on day 45 after increasing the dietary DON content in the experimental diet. Herein, down-regulations of IL-1β, IL-8 and TNFα were demonstrated. In conclusion, the present study provides data concerning chronic application of DON in low doses, as little is known in this area. Down-regulations of immune-related transcription factors and pro-inflammatory immune factors could be demonstrated.

Effect of Fusarium toxin‐contaminated triticale and forage‐to‐concentrate ratio on fermentation and microbial protein synthesis in the rumen

In this study, the effect of Fusarium toxin-contaminated triticale (FUS) at high (60%) and low (30%) concentrate proportion in ruminant rations on ruminal fermentation, microbial protein synthesis and digestibility was investigated, using in vivo and in vitro methods. Significant effects of the forage-to-concentrate ratio on ruminal degradation and digestibility of crude nutrients and detergent fibre fractions as well as on the pH value and the concentration of short chain fatty acids (SCFA) in rumen fluid were found. The production of SCFA was affected, and the degradation of crude fibre and neutral detergent fibre in the rumen was reduced by the inclusion of FUS at high concentrate proportion. The efficiency of microbial crude protein synthesis was higher in diets with 60% than in diets with 30% concentrates, but was impaired in the presence of FUS in vitro at the high concentrate level. Marginal effects of FUS on the amino acid pattern of microbial protein were detected. It was concluded that the use of FUS in high concentrate diets can influence ruminal fermentation and microbial protein synthesis at a dietary deoxynivalenol concentration below 5 mg/kg dry matter.

Decontamination and detoxification strategies for the Fusarium mycotoxin deoxynivalenol in animal feed and the effectiveness of microbial biodegradation

Trichothecenes are a group of mycotoxins mainly produced by fungi of the Fusarium genus. Deoxynivalenol (DON) is one of the most abundant and important trichothecenes in food and feed, and is a significant contaminants due to its frequent occurrence in toxicologically relevant concentrations worldwide. Since toxin production depends strongly on environmental conditions, such as temperature and humidity, Fusarium toxin contamination can not be avoided completely. Therefore, exposure to this toxin is a permanent health risk for both humans and farm animals. As cereal crops are commonly contaminated with DON and animal diets consist mainly of cereals, it can be assumed that animals are frequently exposed to DON-contaminated feeds. Many strategies can be undertaken to reduce the toxic effect of DON. In addition to the general necessity for minimizing all risk factors that might influence the contamination of cereals with DON, such as the so-called field toxins before harvest, several post-harvest strategies can be applied to counteract possible deleterious effects of this mycotoxin in farm animals. Another approach for decontamination in feedstuffs is the use of adsorbent materials. Adsorbent materials may bind mycotoxins in the gastrointestinal tract and reduce absorption and systemic toxicity. It has been shown that some adsorbents are suitable to alleviate the toxic effects of specific mycotoxins, but its efficacy against trichothecenes is practically zero. Therefore, alternative strategies to reduce animal and human health risk are needed. The use of microbial additives is a method which uses microorganisms having the capability to detoxify mycotoxins by metabolism or degradation prior to their resorption in the gastrointestinal tract. DON has been reported to be completely transformed to de-epoxy-DON by ruminal and intestinal microflora. Eubacterium BBSH 797 was capable of DON degradation and counteracted the toxic effects of DON in animals. This review focuses on the efficacy of microbial feed additives in ameliorating the toxic effects of DON. According to the results of experiments to date, it appears that microorganisms are the main living organisms suitable for this mycotoxin biodegradation. However, the use of this approach depends on its effectiveness from both a practical and economic perspective.

Deoxynivalenol suppresses circulating and splenic leukocyte subpopulations in BALB/c mice: dose response, time course and sex differences

It was hypothesized that suppression of peripheral blood leukocyte subsets were markers of exposure to dietary deoxynivalenol (DON), a Fusarium graminearum mycotoxin in grain, at 1.0 mg kg−1 but not at lesser doses in BALB/c mice. Groups of 10 female and 10 male BALB/c mice were fed 0, 0.25, 0.5, 1.0, and 2.0 mg kg−1 DON for 14 and 28 days. Using flow cytometry with staining for leukocyte surface markers, the percentage of CD19+ leukocytes (B cells) in peripheral blood was decreased in both sexes of BALB/c mice after 14 days of exposure to 1.0 or 2.0 mg kg−1 DON, whereas exposure to DON over 28 days did not inhibit B cells compared to the control diet. The percentage of mononuclear cells in peripheral blood was decreased in female BALB/c mice fed 1 and 2 mg kg−1 DON after 14 days compared with control diet. The percentage of CD11b+ leukocytes (monocytes) in peripheral blood and total CD11b+ splenic leukocytes were decreased only in female mice fed 1.0 and 2.0 mg kg−1 DON after 28 days compared with control diet, which shows the greater sensitivity to DON in females compared to males. It was concluded that BALB/c mice adapted to DON exposure because peripheral blood cellular effects of DON at 14 days disappeared by 28 days with the exception of monocyte changes in females. This suggests that female sex hormones potentiate one potential marker of DON immunotoxicity in BALB/c mice.

Sample clean-up methods, immunoaffinity chromatography and solid phase extraction, for determination of deoxynivalenol and deepoxy deoxynivalenol in swine serum

Concentrations of deoxynivalenol (DON) and deepoxy deoxynivalenol (DOM-1) in animal blood are important parameters for studies in toxicology and biological detoxification of DON. Clean-up methods, using either immunoaffinity chromatography (IAC) or solid phase extraction (SPE), were compared in order to determine the free form of DON or DOM-1 and the sum amount (free form plus glucuronide conjugated form of DON or DOM-1), respectively, in swine serum. Detection was achieved by high performance liquid chromatography with ultraviolet detection (HPLC-UV). Compared with the SPE-HPLC method, the IAC-HPLC method provided lower quantitation limit (DON: 18 vs 42ng/ml; DOM-1: 21 vs 30ng/ml) and higher recoveries (DON: 93.4-102.7% vs 63.7-85.3%; DOM-1: 85.5-91.1% vs 68.0-82.6%). Compared with previously published methods, the developed IAC-HPLC method removed analytical interferences from swine serum in one quick and easy step, and eliminated steps of extraction with organic solvent and/or pre-purification using SPE cartridges. This IAC-HPLC method was used to analyze swine serum samples collected from pigs that were evaluated in a feeding trial of a microbiological detoxification of DON. No DON or DOM-1 were detected in serum samples from pigs given a toxin-free diet or a microbial control diet. In serum samples from pigs given a DON diet (5mg/kg of DON), free form DON and sum free DON + conjugated DON were 38.8 ± 13.7 and 49.8 ± 14.1ng/ml, respectively. In serum samples from those given a detoxified-DON diet (DON was transformed to DOM-1), free form DOM-1 was detected but not quantified, and the sum DOM-1 was found as 47.5 ± 6.3ng/ml.

Effects of a diet containing fusarium toxins on the fertility of gilts and on bulbourethral gland weight in barrows

Nine gilts weighing 80 kg at the beginning of the trial were fed a mycotoxin contaminated diet containing 2 mg deoxynivalenol (DON) and 0.4 mg zearalenone (ZON) per kg (Diet M). Their daily weight gain until 103 kg BW was reduced in comparison to the nine control animals fed an uncontaminated diet (Diet C) (763 vs. 912 g; p = 0.02). There was no treatment effect on the age at first observed oestrus. Seven and eight gilts receiving Diet M and C, respectively, became pregnant after being mated once or being again mated three weeks later. The examination of the uteri of gilts slaughtered 35–61 days after mating showed that the exposure to DON and ZON had no effect on the number of foetuses per gilt (p = 0.54), but increased their growth rate (p = 0.003). Thus, low dietary DON and ZON levels had no negative effects on the reproductive parameters examined. The hypothesis that the bulbourethral gland weight of barrows can be used for the bioassay of low dietary ZON levels was rejected since feeding Diet M from 80–103 kg BW did not increase the weight of that accessory sex gland (p = 0.51).

The Impact of the Fusarium Toxin Deoxynivalenol (DON) on Poultry

Deoxynivalenol (DON), a trichothecene, is prevalent worldwide in crops used for food and feed production. The presence of mycotoxins in poultry feeds is a significant factor for financial losses to animal industries. Although DON is one of the least acutely toxic trichothecenes, it should be treated as an important food safety issue because it is a common contaminant of grains. Special care must be taken in so-called “Fusarium years”. As poultry is regarded to be less sensitive to DON compared to other species it is suspected to divert the infected cereal batches to poultry feeding. This review focuses on the ability of DON to induce toxicologic and immunotoxic effects in chickens. Chickens and laying hens respond to increasing dietary DON concentrations with a reduction in productivity only at high levels above 5mg/kg but there is no clear evidence of a dose-response relationship. The main effect at low dietary concentrations appears to be a reduction in food consumption (anorexia), while higher doses induce severe reduction in weight and impaired resistance to infection, particularly bacterial infection. One important aspect of DON toxicity is injury to the gastrointestinal tract. DON has an influence intestinal morphology of chickens, especially in the duodenum and jejunum, as evidenced by shorter and thinner villi. Additionally, DON decreased the intestinal nutrients absorption (glucose and amino acid) in the chicken small intestine in vivo and In vitro. The capacity of DON to alter normal immune function has been of particular interest. There is extensive evidence that DON impairs the immune function in broiler and Leghorn chicks. DON induced changes in the haematopoietic system of chicks and altered the mitogen-induced proliferation of lymphocytes. The feeding of DON contaminated grains decreases serum antibody titers against Newcastle disease virus (NDV) and infectious bronchitis virus (IBV) in laying hens and broilers. Other effects include superinduction of cytokine production by T helper cells (In vitro) and activation of T cells to produce a proinflammatory cytokine. To what extent the elevation of cytokines contributes to metabolic effects such as decreased feed intake remains to be established. Further toxicological studies on the impact of DON in the immune system and gastrointestinal tract of poultry are warranted.

Practically relevant concentrations of deoxynivalenol in diets for growing-finishing pigs offered as mash or pellets

A complete 2×3 two factorial design was applied to investigate the effects of Fusarium-infected wheat (2.5 mg DON/kg, 0, 25 and 50% of the diets), feed processing (mash and pellets) and the interactions thereof on fattening pigs (96, n = 16/group). Feed-to-gain ratio was significantly increased by contaminated wheat (2.65; 2.62 and 2.73 kg/kg for diets containing 0, 25 and 50%Fusarium-infected wheat, respectively) while digestibility of nutrients and metabolizable energy were not affected by the wheat batch. The feed processing also resulted in significant differences in feed-to-gain ratio but was accompanied by significant effects on the digestibility of organic matter and crude fat and on the metabolizable energy. Clinical chemical parameters were not significantly altered by the inclusion of the infected wheat. The lymphocyte proliferation capacity was not significantly affected by any of the experimental factors. A contribution of the feed processing to the variation of the deoxynivalenol (DON) effect may not be deduced from the present results.

On the interactions between Fusarium toxin-contaminated wheat and non-starch-polysaccharide hydrolysing enzymes in turkey diets on performance, health and carry-over of deoxynivalenol and zearalenone

1. Diets with increasing proportions of Fusarium toxin-contaminated wheat (0, 170, 340 and 510 g CW/kg) were fed to male turkeys (BUT Big 6) from d 21 to d 56 of age. Each diet was tested with or without a non-starch-polysaccharide (NSP) hydrolysing enzyme preparation. Dietary deoxynivalenol (DON) and zearalenone (ZON) concentrations were successively increased up to approximately 5·4 and 0·04 mg/kg, respectively. 2. Weight gain decreased slightly with increasing proportions of CW, by 1·6, 0·7 and 3·6%, whereas other performance parameters remained unaffected. NSP enzyme supplements to the diets had no influence. 3. The weight of the emptied jejunum plus ileum, relative to live weight, decreased in a dose-related fashion whereby the NSP enzyme exerted an additional weight-decreasing effect. A similar weight-decreasing NSP enzyme effect was noted for heart weights. Activity of glutamate dehydrogenase in serum was significantly increased in groups fed the diets with the highest CW proportion, whereas γ-glutamyl-transferase remained unaltered. 4. Viscosity in the small intestine was significantly reduced by supplementing the diets with the NSP enzyme. This effect successively decreased with increasing proportions of the CW. 5. Concentrations of DON and of its de-epoxidised metabolite de-epoxy-DON in plasma, liver and breast meat were lower than the detection limits of 2 ng/ml (plasma) and 4 ng/g, respectively, of the applied HPLC method. DON concentration in bile reached up to 13 to 23 ng/ml whereas de-epoxy-DON concentration was lower than 4 ng/ml. 6. ZON or its metabolites were not detectable in plasma, liver or breast meat (detection limits of the HPLC method were 1, 0·5 and 5 ng/g for ZON, α-zearalenol (ZOL) and β-ZOL, respectively). Concentrations of ZON and α-ZOL in bile increased with dietary ZON concentration. The mean proportions of ZON, α-ZOL and β-ZOL of the sum of all three metabolites were 19, 77 and 4%, respectively.

Efficacy of Dietary Selenium to Counteract Toxicity of Deoxynivalenol in Growing Broiler Chickens

The aim of this study was to evaluate the effect of deoxynivalenol on plasma indicators and efficacy of dietary selenium to counteract toxicity of deoxynivalenol in growing broiler chicks. Three groups of broilers were formed with 14 birds in each group. Three diets included control (0.2 ppm deoxynivalenol, 0.4 mg selenium/kg diet), deoxynivalenol-contaminated (3 ppm deoxynivalenol, 0.4 mg selenium/kg diet) and deoxynivalenol-contaminated (3 ppm deoxynivalenol) plus selenium-enriched yeast (1.4 mg selenium/kg diet). After 6 weeks of feeding all birds were sacrifi ced and blood samples for chemical analyses were collected. Plasma calcium, chloride and alanine aminotransferase activity were signifi cantly elevated and magnesium, total proteins, triglycerides and free glycerol were decreased in chicks fed deoxynivalenol-contaminated diet compared with those fed the control diet. Supplementation of selenium-enriched yeast to the diet reversed plasma levels of calcium, magnesium and alanine aminotransferase activity in chicks induced by dietary deoxynivalenol. Phosphorus, albumin and cholesterol levels and alkaline phosphatase, aspartate aminotransferase and lactate dehydrogenase activities were not affected by diets. The inclusion of selenium to DON-contaminated diet, however, did not completely alleviate toxic effect on protein and lipid metabolism by the liver. Supplementation of selenium-enriched yeast product counteracted most of the plasma indicator alterations caused by deoxynivalenol-contaminated diet in chicks.

Effect of the Fusarium toxin deoxynivalenol (DON) on IgA, IgM and IgG concentrations and proliferation of porcine blood lymphocytes

An important effect of the trichothecene mycotoxins is the impairment of the immune function, but immunotoxicity studies have mainly been conducted on the mouse model. In the present study, the effect of deoxynivalenol (DON) on the proliferation of ConA stimulated porcine peripheral blood lymphocytes (PBL) was assessed in vitro after adding of 70–560 ng DON per ml medium, and in vivo after chronic and acute (one single dose) dietary DON exposure (5.7 mg/kg). Immunoglobulin (IgA, IgG, IgM) concentrations were measured by ELISA in supernatants and serum of pigs. The proliferation rate was estimated with two different assays (BrdU incorporation and MTT cleavage). In vitro the ConA stimulated proliferation was inhibited to 50% (IC 50) at 200 and 309 ng DON/ml for the BrdU and MTT assay, respectively, indicating a higher sensitivity of DNA synthesis to DON. Immunoglobulin concentrations in the supernatant after in vitro proliferation of PBL with increasing DON concentrations for 72 h were significantly decreased, with IC 50 values of 120.6, 84.1 and 71.7 ng DON/ml for IgA, IgM and IgG, respectively. In vivo significant inhibition of lymphocyte proliferation was observed only in the DON acute group using the MTT assay, but values tended to be decreased in the BrdU assay and after chronic DON exposure. Immunoglobulins (IgA, IgM and IgG) in the supernatant of cultured lymphocytes were not significantly affected after dietary DON exposure. Serum IgA of pigs showed no significant differences between the groups, whereas IgM and IgG were significant increased in the DON acute group.

Low-Level Dietary Deoxynivalenol and Acute Exercise Stress Result in Immunotoxicity in BALB/c Mice

We hypothesized that acute exercise stress would exacerbate immunosuppressive effects of sub-acute exposure to dietary deoxynivalenol (DON). Male BALB/c mice were fed 0 or 2 mg DON/kg diet for 14 days, 12 animals per dose, and then exercised to fatigue on a treadmill. Mice were euthanized by decapitation, trunk blood and spleens were collected. Single-cell suspensions of splenocytes were used to quantify immune function by plaque hemolysis and conconavalin-A (ConA) stimulated lymphocyte proliferation assays. Serum corticosterone level was determined by enzyme immunoassay. Only the nonexercised DON-fed mice showed significant splenocyte proliferation suppression, 32.9 ± 17.9% of nonexercised controls (p = 0.021). Exercised controls and DON-fed exercised animals showed splenocyte proliferation of 68–75% of nonexercised controls. Antibody response to a T-dependent antigen, sheep red blood cells, was significantly less for exercised DON-fed mice than in controls (p = 0.031). Serum corticosterone levels were significantly higher for both exercised groups compared to the unexercised groups (p < 0.001). IL-4 secretion from mitogen-stimulated splenocytes was elevated by DON alone (p < 0.05) while IL-2 was elevated by DON with exercise stress (p < 0.05). Our hypothesis was confirmed with respect to T-lymphocyte-dependent antibody production, but not for splenocyte proliferation. Exercise stress abrogated DON-mediated suppression of splenocyte proliferation, perhaps mediated by induction of elevated stress hormones counteracting cytokine expression alterations of DON.

Effects of feeding diet contaminated with deoxynivalenol on plasma chemistry in growing broiler chickens and the efficacy of glucomannan mycotoxin adsorbent

The aim of this study was to evaluate effects of modified glucomannan (Mycosorb®) on plasma chemistry of broiler chicks after deoxynivalenol (DON) inclusion in the diet from hatching to 6 weeks of age. Three groups of broiler chicks were formed with 14 birds in each group. The three diets included control (0.2 ppm deoxynivalenol), deoxynivalenol-contaminated (3 ppm deoxynivalenol) and deoxynivalenol- contaminated (3 ppm deoxynivalenol) plus Mycosorb®(2 g/kg diet). After 6 weeks of feeding all birds were sacrificed and blood samples for chemical analyses were collected. Serum calcium and alanine aminotransferase activity were significantly elevated and magnesium, total protein, triglycerides and free glycerol were decreased in chicks fed deoxynivalenol-contaminated diet compared with those fed the control diet. Inclusion of Mycosorb®in the diet decreased plasma alkaline phosphatase and alanine aminotransferase activities and reversed plasma levels of magnesium, triglycerides, free glycerol and total protein in chicks induced by dietary deoxynivalenol. Chloride level was not affected by diets. The inclusion of Mycosorb® to DONcontaminated diet, however, did not prevent or alleviate toxic effect on calcium metabolism. Supplementation of modified glucomannan Mycosorb® counteracted most of the plasma parameter alterations caused by deoxynivalenol-contaminated diet in chicks.

Bioavailability of the Fusarium toxin deoxynivalenol (DON) from naturally contaminated wheat for the pig

Experiments were carried out with 16 castrated male pigs (41.5 ± 2.0 kg) to examine the toxicokinetics of deoxynivalenol (DON) from naturally contaminated wheat (16.6 mg DON/kg) after chronic exposure or one single oral dose (acute). The systemic absorption (bioavailability) of DON was estimated based on the area under the curves (AUC) after oral (chronic or acute) and intravenous application of pure DON (53 μg/kg live weight). Additionally, a balance study was conducted to quantitatively trace the DON metabolism. After intravenous (IV) DON application ( n = 5), serum DON concentrations decreased biphasically with terminal elimination half-lives ( t 1/2 β) of between 4.2 and 33.6 h. DON was rapidly absorbed following oral exposure and reached maximal plasma concentrations ( C max) of 21.79 and 15.21 ng DON/ml serum after ( t max) 88.4 and 99.1 min in the chronic ( n = 5) and acute ( n = 6) fed group, respectively. Thereafter serum DON levels declined slowly with an elimination half-life ( t 1/2 β) of 6.28 and 5.32 h for both oral groups. The mean bioavailability ( F) of DON was 89% for the chronic group and 54% for the acute oral group. DON was highly distributed in all groups, with an apparent volume of distribution ( V d) higher than the total body water. Glucuronide conjugation of deoxynivalenol was found in serum samples after oral exposure, but not after intravenous application. Dietary DON caused a significant increase in DON concentrations of urine and faeces, whereby the metabolite de-epoxy-DON was found only in the trials with a pre-period of longer than 4 weeks. The total recovery was 66.6 ± 39.0% and 54.0 ± 9.7% for the control and the chronic DON groups, respectively, with urine being the main excretory route. In conclusion, orally administered DON was quickly absorbed to an extent of over 50%, highly distributed and only poorly metabolized. Twenty-four hours following oral dosing, DON could not be detected in the serum, except in one chronically fed pig at the level of the detection limit.

The influence of the mycotoxin deoxynivalenol on jejunal glucose transport in pigs

The experiments were aimed at evaluating whether the activity of the glucose transporter in the pig's jejunum is affected by deoxynivalenol (DON)-contaminated feed. This is based on the ability of DON to inhibit the protein synthesis on cellular level which might also involve the synthesis of the intestinal glucose transporter.Two groups of six castrated male pigs were restrictively fed a control or a DON contaminated diet (=5.7 mg/kg). Immediately after slaughtering the pigs, the mid-jejunum was quickly dissected, washed, frozen and stored at -80°C until preparations. Brush border membrane vesicles (BBMV) were prepared by Mg(2+)-EGTA-precipitation and differential centrifugation. The activity of the glucose transporter was examined by measuring the uptake of [(3)H]-glucose into the BBMV. The glucose uptake was quantified by using the rapid filtration technique.The glucose uptake into BBMV followed Michaelis-Menten-kinetic. Comparison of the kinetic parameters Vmax (transport capacity) and Km (transport affinity) of the two treatment-groups showed no significant differences between feeding a DON-contaminated or control diet. It was concluded that dietary DON exposure (=5.7 mg/kg) for five weeks had no obvious influence on the intestinal glucose transporter and its activity in pigs.