Co-occurrence of mycotoxins in swine feed produced in Portugal

A total of 404 samples of commercial swine feed from Portugal feed mills were analysed by HPLC methods for the presence of mycotoxins: 277 samples of feed for fattening pigs were analysed for ochratoxin A (OTA), zearalenone (ZEA), and deoxynivalenol (DON), and 127 samples of feed for sows were analysed for ZEA and fumonisins (FB₁ + FB₂). Concerning feed for fattening pigs, 21 (7.6%) samples were positive for OTA, (2–6.8 μg/kg), 69 (24.9%) were positive for ZEA (5–73 μg/kg), and 47 (16.9%) were positive for DON (100–864 μg/kg). In feed for sows, the results showed 29.9% of positive samples for ZEA (5–57.7 μg/kg) and 8.7% positive samples for FB₁ and FB₂ (50–391.4 μg/kg). Co-occurrence of DON/ZEA was found most frequently, but simultaneous contamination with OTA/ZEA and OTA/DON was also found.     

Zearalenone,deoxynivalenol and aflatoxin B<Subscript>1</Subscript> and their metabolites in pig urine as biomarkers for mycotoxin exposure

Methods to determine zearalenone (ZEA), deoxynivalenol (DON), aflatoxins (AF) and their metabolites in pig urine were developed as biomarkers for pig exposure to the mycotoxins in feed. Urine samples were incubated with β-glucuronidase to cleave conjugates, extracted and cleaned-up with solid phase and immunoaffinity columns, followed by HPLC with UV and fluorescence detection. Good recoveries (83–130%), low variation (2–10%), and low detection limits (0.3–9.9 ng/ml) were obtained. The results of controlled AFB₁ feeding trials found no difference in urine concentrations of AFB₁ or AFM₁ from pigs fed three different levels (127, 227, 327 μg/kg) of AFB₁ in diets. The excretion of AFB₁ and AFM₁ in urine was on average 30% of the oral dose and the ratio AFB₁ to AFM₁ was around 23%. The analysis of 15 Vietnamese pig urine samples indicate a relatively high exposure of ZEA, DON and AF, which were found as toxin or metabolites in 47, 73, and 80% of the urine samples, respectively.     

Effects of deoxynivalenol (DON) and related compounds on bovine peripheral blood mononuclear cells (PBMC) in vitro and in vivo

The Fusarium toxin deoxynivalenol (DON) often co-occurs along with the acetylated derivatives 3-acetyl-DON and 15-acetyl-DON in diets for ruminants. De-epoxy-DON is formed by rumen micro-organisms, while the acetylated DON derivatives might also undergo ruminal metabolism with de-epoxy-DON as an end product. However, despite the fact that de-epoxy-DON is the predominant substance finally absorbed, a complete degradation of the mother compounds can not be assumed for all feeding and metabolic situations of the cow, and thus raising the question of their possible post-absorptive effects. Hence, the aim of the study was to examine the effects of all four compounds on the concanavalin A stimulated proliferation of bovine peripheral blood mononuclear cells (PBMC) using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) as indicator in vitro and ex vivo. Among the DON-related compounds, DON and 15-acetyl-DON resulted in a similar IC₅₀ (i.e. the concentration where the proliferation was inhibited by 50%) of 0.5 μM, whereas 3-acetyl-DON was less toxic (IC₅₀ = 2.6 μM), while actually no IC₅₀ could be estimated for de-epoxy-DON which was characterized by a maximum inhibition of approximately 24% at the highest tested in vitro concentration of 18.29 μM. For the in vivo experiment, 14 Holstein cows were used and fed either an uncontaminated control diet (CON) or a diet contaminated with Fusarium toxins, with DON being the predominating toxin for 18 weeks when blood was collected for PBMC isolation and subsequent proliferation/viability assay. The complete diets for the CON and FUS group contained 0.4 and 4.6 mg DON/kg DM, respectively, at that time. Exposure of dairy cows to the FUS diet resulted in maximum serum de-epoxy-DON levels of 52 ng/ml (0.19 μM), while levels of the unmetabolized DON reached maximum levels of 9 ng/ml (0.03 μM). The PBMC of these cows were slightly less viable, by approximately 18% (p = 0.057), while stimulation capability was not decreased at the same time. Although de-epoxy-DON was characterized by the lowest in vitro toxicity among the tested DON-related compounds, there appeared to be a lower viability of the PBMC isolated from cows fed the FUS diet, which had nearly exclusively de-epoxy DON in serum beside slight traces of unmetabolized DON. Thus, the factors responsible for these apparent discrepancies need to be clarified.     

On the effects of the <Emphasis Type="Italic">Fusarium</Emphasis> toxin deoxynivalenol (DON) administered per os or intraperitoneal infusion to sows during days 63 to 70 of gestation

Six pregnant sows of 180.6 ± 5.6 kg were fed either a Fusarium-contaminated (4.42 mg DON and 48.3 μg ZON per kg, DON per os, n = 3) or a control diet (0.15 mg DON and 5 μg ZON/kg) in the period of days 63 and 70 of gestation. On day 63 of gestation, sows fed the control diet were implanted with an intraperitoneal osmotic minipump (delivery rate of 10 μL/h, for 7 days) containing 50 mg pure (98%) DON in 2 ml 50% DMSO (DON ip, n = 3). Frequent plasma samples were taken to estimate the kinetics after oral and ip DON exposure. The intended continuous delivery of DON by the intraperitoneal minipump could not be shown, as there was a plasma peak (C_max) of 4.2–6.4 ng DON/mL either immediately (sow IP-2+3) or 2.5 h (sow IP-1) after implantation of the pump followed by a one-exponential decline with a mean half-time (t_1/2) of 1.75–4.0 h and only negligible DON plasma concentrations after 12 h. Therefore, the DON ip exposure has to be regarded as one single dose 1 week before termination of experiment. The DON per os sows showed a mean basis level (after achieving a steady state) of DON plasma concentration of about 6–8 ng/mL, as also indicated by the plasma DON concentration at the termination of the experiment. On day 70, caesarean section was carried out, the fetuses were killed immediately after birth, and samples of plasma, urine, and bile were taken to analyze the concentration of DON and its metabolite de-epoxy-DON. At necropsy there were no macroscopic lesions observed in any organ of either sows or piglets. Histopathological evaluation of sows liver and spleen revealed no alterations. The proliferation rate of peripheral blood mononuclear cells (PBMC) with or without stimulation was not affected by the kind of DON treatment. The exposure of pregnant sows at mid-gestation (days 63–70, period of organogenesis) to a Fusarium toxin-contaminated diet (4.42 mg DON and 0.048 mg ZON per kg) or pure DON via intraperitoneal osmotic minipump did not cause adverse effects on health, fertility, maintenance of pregnancy, and performance of sows and their fetuses. However, DON was detected in fetus plasma, indicating that this toxin can pass the placental barrier and may cause changes in the proportion of white blood cells (lower monocyte and neutrophil and higher lymphocyte proportion in DON per os fetuses).     

Metabolisierung von Deoxynivalenol beim Schwein: Bestimmung von DON und DOM-1 im Urin vom Schwein

This paper describes a feeding study with 7 pigs, which were fed with deoxynivalenol contaminated oats at a level of 0.23 mg/kg body mass/day over 16 experiment days. The contamination level of consumed feed was 14.4 mg DON/kg in the ration. The parallel control group of 7 pigs were fed with DON free oats. Urine samples were taken each two days. The content of DON and DOM-1 (de-epoxy deoxynivalenol) in urine was determined. The mean concentration of DON in urine of animals in trial group was 580 μg/l, whereas DOM-1 32 μg/l.     

Carry-over of deoxynivalenol into eggs of laying hens — Preliminary results

Carry-over of deoxynivalenol (DON) into eggs was investigated within the scope of a 16-week experiment with laying hens, in which the birds were fed a maize-based diet containing DON at 11.9 mg/kg dry matter. Eggs were collected during weeks 2, 4, 8, and 16. DON and its metabolite deepoxy-DON were analysed separately in freeze-dried yolk and albumen. Yolk was extracted with water and the extract was purified using an immunoaffinity column (IAC). Albumen was extracted with acetonitrile-water and the extract was pre-cleaned before applying an IAC. All albumen and some yolk samples were incubated with β-glucuronidase prior to extraction. DON and de-epoxy-DON were determined by high performance liquid chromatography (HPLC) with diode array detection (DAD). The detection limits of both toxins were 20 ng/g and 15 ng/g in freezedried yolk and albumen, respectively, corresponding to approximately 10 ng/g and 2 ng/g in fresh samples. The recovery of DON/de-epoxy-DON in spiked samples (50–200 ng/g) was 87/83% (yolk) and 87/77% (albumen) with coefficients of variation of 4–15%. Neither DON nor de-epoxy-DON were detected in any of the samples. In order to achieve lower detection limits, the methods are currently optimized. However, these preliminary results indicate that eggs do not contribute significantly to the dietary DON intake of the consumer. Presented at the 26^th Mykotoxin-Workshop in Herrsching, Germany, May 17–19, 2004     

Effects of deoxynivalenol (DON) in the lactation diet on the feed intake and fertility of sows

A diet contaminated with 2.8 mg deoxynivalenol (DON)/kg was fed at 6 kg per day to 32 mycotoxin-exposed pluriparous sows (M) during lactation. The 31 control sows (C) received 6 kg of an uncontaminated diet. Although more contaminated diet was refused (P = 0.05), DON exposure had no effect (P > 0.1) on body weight loss of the sows during lactation (M: 27.9 ± 12.3 kg; C: 29.7 ± 10.2 kg), the number of weaned piglets (M: 9.8 ± 1.4; C: 9.7 ± 1.6) and their daily weight gain (M: 266 ± 70 g; C: 272 ± 64 g). Several sows were culled after weaning for reasons unrelated to the experiment. Compared with the remaining 21 C sows, the remaining 26 M sows had an identical interval between weaning and the next farrowing (M: 120 ± 1 days; C: 120 ± 1 days) and a similar litter size (M: 14.5 ± 2.7; C: 14.9 ± 3.0; P > 0.10). The daily intake of 17 mg DON during lactation thus did not affect the reproductive performance of the sows.     

Lipopolysaccharides (LPS) modulate the metabolism of deoxynivalenol (DON) in the pig

Pigs might be exposed to lipopolysaccharides (LPS) and deoxynivalenol (DON) at the same time, and both toxins are thought to interactively affect the intestinal barrier, the innate immune system, and the xenobiotics metabolism. Hence, we aimed at examining the single and combined effects of both toxins on nutrient digestibility and DON metabolism. For this purpose, barrows (26?±?4 kg) were fed restrictedly either a control diet (CON) or a diet contaminated with 3.1 mg DON/kg (DON) for 37 days. At day 37 of the experiment, pigs were infused intravenously for 60 min either with 100 μg DON/kg body weight (BW) (CON-DON), 7.5 μg LPS/kg BW (CON-LPS, DON-LPS) or a combination of both substances (CON-DON?+?LPS), or physiological saline (CON-CON, DON-CON). Blood samples were collected frequently until 3.25 h before the pigs were sacrificed for bile, liver, and kidney collection. The apparent digestibility of N-free extractives was significantly increased by 1 % when the DON-contaminated diet was fed. The total DON content in blood was significantly higher in endotoxemic pigs (34.8 ng/mL; CON-DON?+?LPS) when compared to the pigs infused with DON alone (18.8 ng/mL; CON-DON) while bile concentrations were not influenced by LPS. DON residue levels in liver and kidney closely reflected the treatment effects as described for blood. In contrast to DON infusion, the LPS challenge resulted in a significantly lower total DON concentration (13.2 vs. 7.5 ng/mL in groups DON-CON and DON-LPS, respectively) when the pigs were exposed to DON through the diet. The conjugation degree for DON in blood and bile was not influenced by treatments. In conclusion, endotoxemic pigs are characterized by higher DON residue levels in blood, liver, and kidney, probably by a compromised elimination.     

A comparison of deoxynivalenol intake and urinary deoxynivalenol in UK adults

The relationship between deoxynivalenol (DON) intake and first morning urinary DON was examined in UK adults to validate the latter as a biomarker of human exposure. DON was assessed in first morning samples collected during a period of normal diet, a wheat-restriction intervention diet, and partial wheat-restriction intervention in which bread was allowed. During the partial intervention duplicate bread portions were collected for DON analysis. During the normal diet, partial intervention and full intervention, urinary DON was detected in 198/210 (geometric mean 10.1?ng DON mg^?1 creatinine, 95% confidence interval (CI) 8.6–11.6?ng mg^?1; range nd–70.7?ng mg^?1), in 94/98 (5.9?ng mg^?1, 95% CI 4.8–7.0?ng mg^?1; range nd–28.4?ng mg^?1), and 17/40 (0.5?ng mg^?1, 95% CI 0.3–0.7?ng mg^?1; range nd–3.3?ng mg^?1) volunteers, respectively. A strong correlation between DON intake and the urinary biomarker was observed (p <0.001, adjusted r²?=?0.83) in models adjusting for age, sex and body mass index. These data demonstrate a quantitative correlation between DON exposure and urinary DON, and serve to validate the use of urinary DON as an exposure biomarker.     

Research note: Effects of deoxynivalenol on immunohistological parameters in pigs

TheFusarium toxin deoxynivalenol (DON) is known to exert immunomodulatory effects. Numerous studies in mice demonstrated that dietary exposure leads to an upregulation of polymeric serum immunoglobulin A (IgA) suggesting the mucosal immune system as a primary target while at the cellular level T cells and macrophages are involved in this process. The present study aimed to verify these effects in pigs. A total of 24 male pigs were subjected to four treatments, a control group fed a diet devoid of DON, a chronically exposed group receiving a diet containing contaminated wheat (5.7 mg DON/kg diet), an acute orally exposed group receiving only one meal (550 g) of the contaminated feed and an acute intravenous exposed group receiving 53 μg DON/kg body weight. Cryosections of the spleen and the jejunum of the pigs were immunohistologically stained for IgA+, CD3+, CD4+ and CD8+ cells. The number of positive stained cells did not differ significantly between the treatment groups and the control group of any of the specimen.     

Aflatoxin B1, zearalenone and deoxynivalenol production by Aspergillus parasiticus and Fusarium graminearum in interactive cultures on irradiated corn kernels

The influence of inoculum size in the production of aflatoxin B1 (AFB1), zearalenone (ZEN) and deoxynivalenol (DON) was determined when Aspergillus parasiticus NRRL 3000 and Fusarium graminearum ITEM 124 were cultured alone and in pairs on irradiated corn kernels at 28 °C and 0.97 water activity (aw). The highest levels of AFB1 produced by A. parasiticus were produced at the lowest levels of the inoculum (103 spores/ml). No significant differences were observed in ZEN and DON production at any inoculum level during the experimental period. When A. parasiticus was co-inoculated with F. graminearum both to the same inocula (106 spores/ml), AFB1 inhibition percentage were 60, 72 and 56% at 10, 20 and 35 days of incubation respectively, while at 106 spores/ml the percentages of inhibition were 34, 84 and 93% at 10, 20 and 35 days. In the mixture cultures A. parasiticus 103 × F. graminearum 106 spores/ml the percentage of inhibition of AFB1 oscillated in 99% during all the incubation. In the interaction A. parasiticus 106 spores/ml × F. graminearum 103 spores/ml the accumulation of AFB1 decreased in 80, 94 and 86% at 10, 20 and 35 days of incubation respectively. In single culture F. graminearum was inoculated with 10³ or 106 spores/ml and the highest levels of ZEN and DON were detected at 35 days of incubation. The levels oscillated in 538–622 μg/kg for ZEN and 870–834 μg/kg for DON respectively. In paired cultures there were no significant differences in the levels regardless of the spore concentrations during the incubation time. This revised version was published online in June 2006 with corrections to the Cover Date.     

The effect of vitamin E supplementation on reduction of lymphocyte DNA damage induced by T-2 toxin and deoxynivalenol in weaned pigs

The objective of the present study was to establish the effect of deoxynivalenol (DON) and T-2 toxin on lipid peroxidation, lymphocyte DNA fragmentation and immunoglobulin production in weaned pigs, and furthermore, to evaluate the potential of vitamin E (α-tocopheryl acetate) in prevention of toxin mediated changes. Forty-eight weaned castrated male crossbred pigs (mean live weight at the beginning of the experimental period was 11.7 kg) were randomly assigned to five experimental groups: control (without toxin and vitamin E), T-2 (3 mg/kg T-2 toxin), T-2 + E (3 mg/kg T-2 toxin + 100 mg/kg vitamin E), DON (4 mg/kg DON) and DON + E (4 mg/kg DON + 100 mg/kg vitamin E). After 14 days of treatment blood was collected for analysis. Lipid peroxidation was studied by assays of malondialdehyde (MDA), total antioxidant status (TAS) of plasma and erythrocyte glutathione peroxidase (GPx). DNA damage in lymphocytes was measured by comet assay. Serum immunoglobulin levels were evaluated by enzyme-linked immunosorbent assay (ELISA) and the hepatotoxicity was studied by measuring plasma liver enzyme levels (alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ-glutamyl-transferase (GGT). Production parameters of both DON groups were significantly impaired in comparison to the control. DON significantly increased the amount of DNA damage in lymphocytes by 28%. Moreover, the levels of TAS were lowered by addition of DON. T-2 toxin significantly impaired daily live weight gain and feed conversion, increased the amount of DNA damage in lymphocytes by 27%, decreased total serum IgG and did not alter plasma TAS. Plasma and 24-h urinary malondialdehyde (MDA) excretion rate and erythrocyte Gpx levels did not differ among the groups. Supplementation with vitamin E did not improve production parameters impaired by DON and T-2 toxin and only partially protected lymphocyte DNA from toxin impact. To our knowledge, these are the first data on genotoxic effects of moderate doses of DON and T-2 toxin on pig lymphocytes. The effect of DON and T-2 toxin on the immune system was reflected as a change in immunoglobulin synthesis, which might be toxin and species specific. According to other results no major induction of oxidative stress could be proven. Enhancement of antioxidant status with vitamin E in the case of DON and T-2 toxin intoxication can be beneficial for remaining the lymphocyte DNA integrity.     

Mycotoxins in horse feed

A total of 62 samples of commercial horse feed preparations (complementary feeds) containing cereal mixtures (“muesli” or mash, n = 39; pelleted feeds, n = 12), and plain horse feed grains (maize, n = 5; oats, n = 4; barley, n = 2) were purchased from 21 different producers/distributors from the German market. All samples were analysed by competitive enzyme immunoassays (EIA) for six different mycotoxins (mycotoxin groups). Analytes (detection limit, mean recovery) were: deoxynivalenol (DON, 10 μg/kg, 84%), zearalenone (ZEA, 5 μg/kg, 93%), fumonisin B₁ (FB₁, 2 μg/kg, 113%), T-2 toxin (T-2, 0.1 μg/kg, 71%), sum of T-2 + HT-2 toxin (T-2/HT2, 0.2 μg/kg, 97%), ochratoxin A (OTA, 0.2 μg/kg, 67%), and total ergot alkaloids (Generic Ergot Alkaloids “GEA”, 30 μg/kg, 132%). All samples contained DON (16–4,900 μg/kg, median 220 μg/kg), T-2/HT-2 (0.8–230 μg/kg, median 24 μg/kg), and T-2 (0.3–91 μg/kg, median 7 μg/kg). ZEA was detected in 98% of the samples (7–310 μg/kg, median 61 μg/kg). Most samples (94%) were positive for FB₁ (2–2,200 μg/kg, median 27 μg/kg). Ergot alkaloids were detected in 61% of samples (28–1,200 μg/kg, median 97 μg/kg), OTA was found in 42% of samples (0.2–4 μg/kg, median 0.35 μg/kg). The results demonstrate that a co-contamination with several mycotoxins is very common in commercial horse feed from the German market. The toxin concentrations were in most cases well below the levels which are usually considered as critical or even toxic. The highest mycotoxin concentrations were mostly found in single-grain cereal feed: the maximum values for DON and FB₁ were found in maize, the highest T-2/HT-2 toxin concentrations were found in oats, and the highest concentration of ergot alkaloids was found in barley. In composed feeds, no correlation between cereal composition and mycotoxin levels could be found.     

Determination of deoxynivalenol in cereals by HPLC-UV

A simple method for determination of deoxynivalenol (DON) in cereal samples is described. DON was extracted with methanol, the solvent evaporated, and the residue redissolved with water. This extract was purified on immunoaffinity columns. DON was determined by HPLC with UV-detection. The limits of detection (LOD) and quantification (LOQ) were 10 and 50 μg/kg, respectively. Presented at the 25^th Mykotoxin Workshop in Giessen, Germany, May 19–21, 2003     

Fungal diversity and natural occurrence of fusaproliferin,beauvericin, deoxynivalenol and nivalenol in wheat cultivated in Santa Fe Province,Argentina

The Fusarium diversity and the mycobiota associated with moldy wheat kernels from Santa Fe province, Argentine, was assessed. The wheat cultivated area in Santa Fe province is divided according to agrometeorological conditions into two zones: Zone I (north-central) and Zone II (south). The natural occurrence of Fusarium toxins BEA, FUP, DON and NIV was also determined. Cladosporium was the most abundant of the 19 genera identified, followed by Fusarium, Phoma and Alternaria. Zone II shows a predominance of F. graminearum and F. culmorum. In Zone I, DON was present in 13/32 samples (range 0.43–3.60 mg kg⁻¹) and NIV in 6/32 samples (range 0.11–0.40 mg kg⁻¹). In zone II, DON was found in 11/21 samples (range 0.57–9.50 mg kg⁻¹) and NIV in 4/21 samples (range 0.10–0.60 mg kg⁻¹). BEA and FP were not detected in both zones.     

Zearalenone, deoxynivalenol and fumonisins in mixed-feed for laying hens

Fusarium toxins are secondary metabolites produced byfungi of these genera in many commodities under certain conditions. A study was carried out to investigate the co-occurrence of zearalenone (ZEN), deoxynivalenol (DON) and fumonisins (FB₁ and FB₂) in 52 samples of mixed-feed for poultry contaminated withFusarium verticillioides. The zearalenone and deoxynivalenol were checked using immunoaffinity column and the extraction of fumonisin was performed by strong anion exchange (SAX) solid phase column. Detection and quantification were determined by high performance liquid chromatography (HPLC). The limit of detection was 5 μg/kg for ZEN, 100 μg/kg for DON and 50 and 100 μg/kg for FB₁ and FB₂ respectively.Fusarium toxins were detected in 20 samples. Sixteen samples were positive for ZEN (30.7%) presenting levels that ranged from 7.4 μg/kg to 61.4 μg/kg (mean=27.0 μg/kg). 13.5% of the samples presented contaminations of DON, with levels ranging from 100.0 μg/kg to 253 μg/kg (mean=l18.07 μg/kg). FB₁ was detected in 19.2% of samples, with levels ranging from 50.0 μg/kg to 110.0 μg/kg (mean=73.6 μg/kg). FB2 was not detected in any sample. In positive samples simultaneously contamination with two or three mycotoxins were detected in 9 of them (17.3%).     

Aerobic and anaerobic de-epoxydation of mycotoxin deoxynivalenol by bacteria originating from agricultural soil

One hundred and fifty soil samples collected from different crop fields in southern Ontario, Canada were screened to obtain microorganisms capable of transforming deoxynivalenol (DON) to de-epoxy DON (dE-DON). Microbial DON to dE-DON transformation (i.e. de-epoxydation) was monitored by using liquid chromatography-ultraviolet-mass spectrometry (LC-UV–MS). The effects of growth substrates, temperature, pH, incubation time and aerobic versus anaerobic conditions on the ability of the microbes to de-epoxydize DON were evaluated. A mixed microbial culture from one composite soil sample showed 100% DON to dE-DON biotransformation in mineral salts broth (MSB) after 144 h of incubation. Treatments of the culture with selective antibiotics followed an elevated temperature (50°C) for 1.5 h considerably reduced the microbial diversity. Partial 16S-rRNA gene sequence analysis of the bacteria in the enriched culture indicated the presence of at least six bacterial genera, namely Serratia, Clostridium, Citrobacter, Enterococcus, Stenotrophomonas and Streptomyces. The enriched culture completely de-epoxydized DON after 60 h of incubation. Bacterial de-epoxydation of DON occurred at pH 6.0–7.5, and a wide array of temperatures (12–40°C). The culture showed rapid de-epoxydation activity under aerobic conditions compared to anaerobic conditions. This is the first report on microbial DON to dE-DON transformation under aerobic conditions and moderate temperatures. The culture could be used to detoxify DON contaminated feed and might be a potential source for gene(s) for DON de-epoxydation.     

Blood plasma levels of deoxynivalenol and its de-epoxy metabolite in broilers after a single oral dose of the toxin

To evaluate the transfer of deoxynivalenol (DON) and its de-epoxy metabolite (de-epoxy-DON) in the plasma of chicken, mashed oats naturally contaminated with 9.5 mg DON/kg were fed to four broilers (35 days age) at a dose of 20 g/bird. Blood samples were then collected from two birds at 1 h, 3 h, and 5 h post-feeding, while from the other two birds at 2 h, 4 h, and 6 h post-feeding. Analysis of DON and de-epoxy-DON was carried out by using liquid chromatography-tandem mass spectrometry after clean-up with immunoaffinity columns. At 1 h, 3 h, and 5 h post-feeding, the average values of plasma DON were 0.35 ng/ml, 0.20 ng/ml, and 0.15 ng/ml, respectively. The corresponding average values of de-epoxy-DON at these time points were 0.70 ng/ml, 0.80 ng/ml, and 0.25 ng/ml, respectively. The sum of DON and de-epoxy-DON appearing in the plasma at 1 h post-feeding in these birds was estimated to be 0.044% of the total DON fed. At 2 h, 4 h, and 6 h post-feeding, the average values of plasma DON were 0.85 ng/ml, 0.45 ng/ml, and 0.30 ng/ml. De-epoxy-DON could not be detected in the birds sampled at 2 h, 4 h, and 6 h post-feeding. The total amount of DON appearing in the plasma at 2 h post-feeding in these birds was estimated to be 0.036% of the DON fed. These data show that the absorption rate of DON is very low in broilers and that there is also a rapid transformation, and clearance from plasma. Furthermore, there appeared to be individual variability in the capacity of birds to de-epoxidise DON.     

Proteomic analysis of the effects of the immunomodulatory mycotoxin deoxynivalenol

The mycotoxin deoxynivalenol (DON) contaminates cereals worldwide and is a common contaminant in the Western European diet. At high doses, DON induces acute gastrointestinal toxicity; chronic, low‐dose effects in humans are not well described, but immunotoxicity has been reported. In this study, 2‐DE was used to identify proteomic changes in human B (RPMI1788) and T (JurkatE6.1) lymphocyte cell lines after exposure to minimally toxic concentrations (up to 500 ng/mL) for 24 h. Proteins which changed their abundance post treatment, by a greater than 1.4‐fold change reproducible in three separate experiments consisting of 36 gels in total, are ubiquitin carboxyl‐terminal hydrolase isozyme L3, proteasome subunit β type‐4 and α type‐6, inosine‐5′‐monophosphate dehydrogenase 2, GMP synthase, microtubule‐associated protein RP/EB family member 1 (EB1), RNA polymerases I, II, III subunit ABC1, triosephosphate isomerase and transketolase. Flow cytometry was used to validate changes to protein expression, except for EB1. These findings provide insights as to how low‐dose exposure to DON may affect human immune function and may provide mechanism‐based biomarkers for DON exposure.