High Concentrations Of Deoxynivalenol Research Articles

Deoxynivalenol Induces Local Inflammation and Lesions in Tissues at Doses Recommended by the EU.

The mycotoxin deoxynivalenol (DON) is frequently present in cereals at low levels, resulting in its occurrence in food and feed. DON has been proven to alter the immune response and induce inflammation in all species, with pigs exhibiting heightened sensitivity and exposure. However, no study has yet evaluated the effects of exposure to DON at the recommended levels in pig feed. In two separate trials, piglets were subjected to control feed or feed contaminated with a low level of purified DON (0.83 mg/kg feed in trial 1 and 0.85 mg/kg feed in trial 2) for either three weeks (trial 1) or two weeks (trial 2). Additionally, a group of animals exposed to 2.85 mg/kg feed of DON was included as a positive control in Trial 1. The impact of DON on porcine tissues (intestine, liver, and spleen) was evaluated through histological and qPCR analyses of immune-related genes. Additionally, biochemical analyses and acute-phase proteins were examined in plasma samples. Lesions were identified in the intestine (jejunum and ileum), the liver, and the spleen of pigs receiving diets contaminated with low and high concentrations of DON. The low level of DON also resulted in impaired expression of genes associated with intestinal barrier integrity, intestinal immune responses, and liver function. In conclusion, the results of the two trials demonstrate the impact of DON exposure even at doses below the recommended level of 0.9 mg/kg feed set by the European Union. This suggests that the current recommended level should be reconsidered to ensure the optimal health and well-being of pigs.

Effect of Organic and Conventional Cereal Production Methods on Fusarium Head Blight and Mycotoxin Contamination Levels

Fusarium mycotoxins in cereals constitute major problems for animal and human health worldwide. A range of plant pathogenic Fusarium species that can infect cereal plants in the field are considered the most important source of mycotoxins, such as deoxynivalenol (DON), zearalenone (ZEA), T-2 toxin, and HT-2 toxin, in small-grain cereal crops in temperate climates. In this article, we (i) critically review the available knowledge on the impact of contrasting production systems (organic versus conventional) and specific agronomic parameters on the occurrence and concentrations of DON, ZEA, and T-2/HT-2 in small-grain cereals (wheat, oats, barley, and rye), and (ii) discuss Fusarium mycotoxin risks in the context of the need to develop more sustainable cereal production systems. Overall, the available evidence from studies of acceptable scientific quality suggests that the incidence and concentrations of Fusarium mycotoxin are lower in organic compared with conventional cereals. Specifically, 24 comparisons showed lower mycotoxin levels in organic production, 16 detected no significant difference, and only 2 showed higher levels in organic production. When the mean concentrations from all studies were compared, conventionally produced cereals had 62%, 110%, and 180% higher concentrations of DON, ZEA, and T-2/HT-2, respectively, than organic cereals. Overall, published studies on the effects of specific agronomic practices on mycotoxin levels suggest that diverse crop rotations and high soil organic matter content/biological activity are associated with a lower risk of Fusarium mycotoxin contamination, whereas (i) high mineral nitrogen fertiliser inputs, (ii) some fungicides and herbicides, and (iii) minimum or no tillage may increase the risks of Fusarium mycotoxin contamination in cereals. The management of Fusarium head blight and mycotoxins, therefore, requires a preventative, integrated, holistic agronomic approach.

The effect of technological processes on contamination with B-class trichothecenes and quality of spring wheat products from grain harvested at different times

The study aimed to investigate the effect of technological processes on deoxynivalenol (DON), 3-acetyl-deoxynivalenol (3-ADON) and 15-acetyl-deoxynivalenol (15-ADON) concentrations and quality of spring wheat products from grain harvested at different times. In this study, 408 samples were analysed for DON, 3-ADON and 15-ADON contamination by the HPLC method with UV detection. Delays in harvesting due to cool and rainy weather conditions resulted in increased DON, 3-ADON and 15-ADON levels. The highest DON concentrations were determined in bran. Higher DON concentrations in the bran indicate the protective function of the grain hull. On the other hand, the highest levels of minerals have been found in bran and whole grain flours, highlighting the importance of consuming these milling fractions as a mineral source with sustained health benefits. Our results showed that DON is stable at 170 °C, and high DON levels in whole-meal flour and white flour could not be converted or decomposed during baking. The levels of 3-ADON and 15-ADON in whole-meal flour bread and white flour bread were significantly reduced but not completely removed. The levels of DON and its derivatives 3-ADON and 15-ADON were significantly reduced in starch and gluten produced from contaminated whole meal flour; however, the washing process did not completely eliminate these toxic compounds. The concentrations of mycotoxins in starch and gluten remained relatively high. Negative correlation was found in highly contaminated samples between DON and bread baking properties. Also, inverse relationship was found between high mycotoxin concentrations and mineral element content in white flour.

An Agro-Climatic Approach to Developing a National Prevention Tool for Deoxynivalenol in French Maize-Growing Areas.

The levels of deoxynivalenol (DON)—a mycotoxin produced by Fusarium graminearum—in maize for food and feed are subject to European Union regulations. Obtaining a compliant harvest requires the identification of agronomic and climatic risk factors related to higher fungal contamination and DON production. A national, multiyear database for maize was created, based on field survey data collected from 2004 to 2020. This database contains information about agricultural practices, climatic sequences and DON content at harvest for a total of 2032 maize fields localized in the French maize-growing regions. A linear mixed-model approach highlighted the presence of borers, late harvest and inadequate crop residue management, normal-to-cold temperatures in March, humidity in August and the absence of a hot end of the maize development cycle with a dry August as creating conditions favoring maize contamination with DON. The various possible associations between these risky climatic conditions and agricultural practices were compared, grouped and ranked as related to very low to high DON concentrations. Some combinations may even exceed the regulatory threshold. The national prevention tool, created for producers and agricultural cooperatives, is informative and easy-to-use to control the sanitary quality of their harvest.

VPLYV ADITÍV NA MYKOTOXICKÚ KONTAMINÁCIU KUKURIČNÝCH SILÁŽÍ

Addition of silage additives is commonly concentrated on the improvement of nutritive and fermentative features of silages, but in recent years, mycotoxic contamination is also a feature monitored after the treatment. This study aimed to evaluate the effect of silage additives, in the concrete inoculant consisting of a mixture of Lactobacillus buchneri LN40177, Lactobacillus casei LC329090 and urea, on the concentration of major mycotoxins in maize silages. The ensilage mass was made in three variants, which consisted of maize silage (control variant C), maize silage with the addition of a commercial inoculant (variant A) and maize silage with the addition of urea (variant U). The commercial inoculant was added to the cut mass at a dose of 1 g/t of mass and urea at a dose of 5 kg/t of mass. After application of silage additives, the mass was stored and sealed in silage units. Mycotoxin analysis was performed using Veratox tests with ELISA reader, whereas average samples were prepared according to established protocols. The immuno-enzymatic method revealed that all samples of maize silage showed 100% contamination. The maize silages were characterized by the highest concentration of deoxynivalenol regardless of the treatment. The results confirmed the effect of silage additives on mycotoxic contamination of maize silages. Compared to the control variant, the commercial inoculant had negative increasing effect (P<0.05) on deoxynivalenol, ochratoxins and zearalenone, and a positive decreasing effect (P<0.05) on T-2 toxin and fumonisins. The urea addition resulted in significant reduction of T-2 toxin and increase of zearalenone.

Natural Occurrence of Deoxynivalenol in Cereal-Based Baby Foods for Infants from Western Poland.

The study examined 110 samples of baby products based on rice, wheat, maize and multi-grains available on the western Polish market in order to detect the level of deoxynivalenol (DON) by means of HPLC (high-performance liquid chromatography) with a fluorescence detector (HPLC-FLD). DON was detected in 9.09% of the infant food samples, with an average and maximum level of 107.8 ± 30 and 148 μg/kg, respectively. The highest concentration of DON was detected in food for infants: wheat-based (mean 121 ± 7.07, 4.8%), multi-grain (mean 118 ± 5.65, 4.25%) and maize-based (mean 100 ± 37.96; 35.30%). No high DON content and high estimated daily intake were observed in the analyzed products. However, in order to minimize the harmfulness associated with the presence of DON in food for infants and young children, a risk assessment should be performed based on the monitoring results.

Utilising yellow mealworm larvae reared on deoxynivalenol-contaminated wheat as a feed ingredient for poultry diets

This study determined if yellow mealworm larvae (YML) grown on deoxynivalenol (DON) contaminated wheat would affect broiler chicken performance. The YML were reared on wheat with low (LDW; 630 μg/kg) or high (HDW; 30,730 μg/kg) DON concentrations. The DON concentrations in the dried insect meals were 0 or 17.5 μg/kg for YML grown on LDW and HDW, respectively. Seventy-five male Ross 708 broilers were randomly placed into 15 cages and reared on one of three diets from day 1-35 (five replications/treatment). On day 14, broiler numbers were reduced to four per cage. The diets consisted of a control containing no YML meal (CD) and two diets containing 5% YML meal produced on either LDW (LMD) or HDW (HMD). Feed intake and body weight (BW) were measured over the duration of the experiment to calculate feed to gain ratio (F:G). On day 35, all birds were slaughtered and dissected to collect weights of the breasts, thighs, drums, wings, abdominal fat pads, and organs. Crude protein retention was higher in birds fed the LMD and HMD treatments compared to CD (P=0.0091). Dry matter retention was higher in the HMD diet compared to the CD and LMD diets (P=0.0046). Feed intake was lower in birds fed HMD compared to CD and LMD (P=0.0031) although final BW was not reduced. In conclusion, dietary inclusion of YML did not affect the growth, meat yield or organ weights of the birds. The YML reared on DON-contaminated wheat (up to 30,730 ug/kg) and included in broiler diets at 5% could be an effective means of converting salvage wheat into a safe and sustainable source of protein.

Resistance of Winter Spelt Wheat [Triticum aestivum subsp. spelta (L.) Thell.] to Fusarium Head Blight.

Resistance to Fusarium head blight (FHB) of spelt wheat was investigated in field trials carried out at three European locations between 2016 and 2018. Resistance was assessed after artificial inoculation by visual scoring of symptoms and the determination of the contamination of grains and glumes with the mycotoxin deoxynivalenol (DON). It was found that typical spelt traits such as tall plant height, lax spikes, and tough glumes play a role as passive resistance factors. Across all test environments, modern spelt varieties with a significantly reduced plant height showed a significantly higher susceptibility to FHB and a higher contamination of the grains with DON compared to old landraces/varieties and plant genetic resources. Similarly, the lowest mycotoxin levels in grains were found only in old landraces and varieties, while the highest DON concentration was observed mainly in modern varieties. The results obtained can be used for the selection of suitable parental material for breeding spelt with improved FHB resistance.

The Impact of Harvesting Time on Fusarium Mycotoxins in Spring Wheat Grain and Their Interaction with Grain Quality

In this work, we studied the impact of harvesting time on Fusarium mycotoxin occurrence in spring wheat and the effect of mycotoxin contamination on the quality of these grains. The spring wheat grains (Triticum aestivum L.) were collected in 2016–2018 when the crop had reached full maturity, 10 ± 2 days and 17 ± 3 days after full maturity. The grain samples were analyzed for Fusarium infection and co-contamination with mycotoxins deoxynivalenol (DON), zearalenone (ZEA), and T-2 toxin (T-2), as well as the quality of the wheat grains (mass per hectolitre, contents of protein, starch, ash and fat, particle size index (PSI), falling number, sedimentation, wet gluten content, and gluten index). The occurrence of Fusarium spp. fungi and the mycotoxins produced by them in the grains was mostly influenced by the harvesting time and meteorological conditions. The correlations between Fusarium species and the mycotoxins produced by them in the grains of spring wheat showed F. graminearum to be a dominant species, and as a result, higher concentrations of DON and ZEA were determined. The co-occurrence of all the three mycotoxins analyzed (deoxynivalenol, zearalenone, and T-2 toxin) was identified in wheat. In rainy years, a delay in harvesting resulted in diminished grain quality of spring wheat, as indicated by grain mass per hectolitre and falling number. Negative correlations were found in highly contaminated grains between mycotoxins (DON, ZEA, and T-2) and falling number and grain mass per hectolitre values.

Comprehensive dietary and internal exposure assessment of deoxynivalenol contamination in a high-risk area in China using duplicate diet studies and urinary biomarkers

This study assessed the exposure of 199 Chinese population samples from the Anhui Province, China, to deoxynivalenol (DON) based on their dietary intake and urinary biomarkers. This is the first study to compare between both procedures of DON exposure detection (diet study and human bio-monitoring approach) within the same population. Food and urine samples were collected from 199 healthy participants. The highest concentrations of DON and its derivatives were detected in wheat-based products. Both DON and its metabolite, DOM-1, were found in the urine samples. Total (free + conjugated) DON was detected in 99% of the samples, with a mean concentration at 109.21 ng mL−1. The mean estimated dietary intake (EDI) level calculated from food consumption and contamination data was obtained as 2.54 ± 1.63 μg kg−1 bw d−1, while the mean probable daily intake (PDI) based on urinary biomarkers was estimated to be 3.96 ± 4.20 μg kg−1 bw d−1. A significant correlation was evidenced between EDI and PDI, both exceeding the provisional maximum tolerable daily intake. Elevated contaminant levels were observed in the adolescent group compared to children, adults, and elders, thereby indicating a potential health risk in them. The excretion rate of adolescents was approximately 2.5 times that of adult participants, possibly indicative of higher metabolic activity, which needs further in-depth investigation.

Bee-pollen retailed in Tuscany (Italy): Labelling, palynological, microbiological, and mycotoxicological profile

Bee pollen is the result of flower pollen collecting and processing by honey bees. Due to its nutritional profile, it is considered a functional food. The present work aimed at evaluating labelling, pH, Aw, microbiological and mycotoxicological profile of 29 bee pollen samples (dried and fresh) purchased at retail in Tuscany (Italy). Only one pollen lacked more than two mandatory indications. Aw ranged from 0.19 to 0.77, while pH from 4.50 to 6.10. Fresh samples presented higher bacterial loads than dried samples. Total bacterial counts, Enterobacteriaceae, yeasts and molds and lactic acid bacteria ranges were 2.2–6.0, <2–4.1, <1–4 and <2–6.0 log CFU/g, respectively. Escherichia coli, Staphylococcus aureus, Bacillus cereus and sulphite-reducing clostridia loads were lower than the detection limit; Salmonella spp. and Listeria monocytogenes were always absent. As for mycotoxins, total aflatoxins were detected in all samples (5.2–34.4 μg/kg). Higher deoxynivalenol concentrations were detected (maximum: 179.7 μg/kg). Since the occurrence of spoilage microorganisms seems to be frequent, leading to possible alterations of the organoleptic profile, the microbiological quality of fresh bee pollen should be monitored. The risk related to the presence of pathogenic microorganisms seems to be very low, while attention must be paid to the presence of toxic metabolites.

Mycotoxins contamination of maize in Anambra State, Nigeria

ABSTRACTStudies focused on isolation of mycotoxigenic fungi and quantification of mycotoxin contamination of 36 maize samples sold in Anambra State local markets. Duplicate samples of surface sterilised, blended, and serially diluted maize samples were cultured in potato dextrose agar fortified with 0.5mg/ml chloramphenicol. Using twelve randomly selected, blended samples for mycotoxins quantification, two hundred and ninety-two fungal isolates consisting of 20 species of moulds and 7 species of yeasts were isolated. Some recovered isolates were Aspergillus niger (7.87%), Aspergillus flavus (5.48%), Aspergillus fumigatus (4.11%), Penicillium cherasanum (3.08%), P. verrucosum (2.05%), P. marneffei (2.05%), Fusarium oxysporium (5.14%), Fusarium solani (3.42%), Rhizopus oryzae (3.42%), Candida albicans(2.82%), and Saccharomyces cerevisiae (8.56%). Aflatoxin was not found. The determination of mycotoxigenic fungi and high concentrations of deoxynivalenol and zearalenone above the maximum limits is a source of concern as regular consumption of maize containing these mycotoxins could be unsafe for humans or animals.

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

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

Long Term Monitoring (2014⁻2018) of Multi-Mycotoxins in South African Commercial Maize and Wheat with a Locally Developed and Validated LC-MS/MS Method.

Mycotoxins occur worldwide in the major grains, and producers, traders and processors are all challenged to prevent serious health problems for consumers. The challenges originate with pre-harvest fungi infections in the grain fields, increased contamination during improper storage and, finally, the mycotoxin accumulation in commercial food and feed products. Little is known about the multi-mycotoxin occurrence in maize and wheat commercially produced in South Africa. This is the first comprehensive study that reports on the multi-mycotoxin occurrence in South African produced maize and wheat crops after harvest, over four production seasons, in all the production regions of the country. The study was made possible with the development of a fit-for-purpose, cost-effective LC-MS/MS multi-mycotoxin method, validated for 13 “regulated” mycotoxins. A low mycotoxin risk was found in South African produced wheat, with only deoxynivalenol (DON) in 12.5% of the 160 samples at levels well below the 2000 µg/kg South African (SA) regulatory level. It was concluded that aflatoxin B1 (AFB1) is seldom present in South African produced commercial maize. The concentrations, regional variation and seasonal trends of deoxynivalenol and fumonisins, the two most prevalent mycotoxins, and of zearalenone (ZON), are reported for white and yellow maize in all the production provinces, based on the analytical results of 1400 maize samples. A threefold to eightfold increase in deoxynivalenol mean concentrations in white maize was observed in the main production regions in the fourth season, with 8.9% samples above 2000 µg/kg. A strong correlation was found between higher deoxynivalenol concentrations and the presence of 15-acetyl-deoxynivalenol (15-ADON). The mean fumonisin concentrations were well below the 4000 µg/kg South African regulatory value. A possible shift in the incidence and severity of mycotoxigenic Fusarium spp. in the provinces must be investigated. The variations and trends highlight the importance of a continuous monitoring of multi-mycotoxins in South Africa along the grain value chain.

Deoxynivalenol Modulates the Viability, ROS Production and Apoptosis in Prostate Cancer Cells.

Deoxynivalenol (DON), known as vomitoxin, a type B trichothecene, is produced by Fusarium. DON frequently contaminates cereal grains such as wheat, maize, oats, barley, rye, and rice. At the molecular level, it induces ribosomal stress, inflammation and apoptosis in eukaryotic cells. Our findings indicate that DON modulates the viability of prostate cancer (PCa) cells and that the response to a single high dose of DON is dependent on the androgen-sensitivity of cells. DON appears to increase reactive oxygen species (ROS) production in cells, induces DNA damage, and triggers apoptosis. The effects of DON application in PCa cells are influenced by the mitogen-activated protein kinase (MAPK) and NFΚB- HIF-1α signaling pathways. Our results indicate that p53 is a crucial factor in DON-associated apoptosis in PCa cells. Taken together, our findings show that a single exposure to high concentrations of DON (2–5 µM) modulates the progression of PCa.

Wet milling technique applied to deoxynivalenol‐contaminated wheat dry‐milled fractions

AbstractBackground and objectivesThe consumption of wheat contaminated with deoxynivalenol (DON), a highly water‐soluble Fusarium mycotoxin, represents a health threat to animals and humans. Dry milling does not destroy or remove DON from the grain but physically separates the bran and germ from the endosperm. Information is limited concerning the effectiveness of wet milling processes in removing DON from contaminated wheat dry milling fractions (farina/semolina, shorts, bran). The aim of this research was to determine the extent of DON removal from these wheat fractions during wet milling using the Martin process.FindingsAfter wet milling farina and semolina containing 2.76–5.07 mg/kg and 3.53–10.39 mg/kg DON, respectively, gluten extracted from hard red spring wheat (HRSW) contained low levels of DON &lt; 0.60 mg/kg, while gluten extracted from durum wheat (DW) contained no detectable DON. The remainder of DON was found in the water‐soluble fraction. After wet milling shorts, DON levels were only detected in the freeze‐dried water‐soluble fraction. After wet milling the bran fraction, DON was found in isolated starch and destarched bran from HRSW and DW; the highest DON concentration was found in the freeze‐dried water‐soluble fraction accounting 83% and 88% in HRSW and DW, respectively.ConclusionsResults indicated that wet milling was effective in removing DON from the studied dry‐milled fractions.Significance and noveltyThe implementation of the wet milling technique could be useful in reducing or eliminating DON from dry milling products, which would allow them to be used in animal and human food.

The influence of milling and sifting processes on deoxynivalenol distribution in whole-wheat flour and its products

Milling and sifting of grain are important processes that affect mycotoxin distribution in the chain of grain products. The level of deoxynivalenol (DON) in white flour cannot be reduced by sifting because it is concentrated within a specific white flour fraction. The objective of this study was to investigate the influence of milling and sifting processes on the reduction of DON contamination in whole-wheat flour and in the chain of spring wheat products (grain – bran – white flour – white flour fractions) from artificially and naturally (2016) and naturally (2017) infected grain samples. The current study showed that the distribution of DON in the grain products (whole-wheat flour – bran – white flour) depends on the weather conditions of the season and grain contamination level. This was particularly evident in the naturally contaminated grain in 2017. The highest DON concentrations were determined in bran. Higher DON concentrations in the bran from the naturally infected grain indicate the protective function of the grain hull, which provides partial protection for grain embryo against higher contamination. With a delay in harvesting, which resulted in increased DON concentrations, bran remained the most contaminated product; however, this was not true for the products from artificially infected grain. The DON level in bran was not significantly different atP&lt;0.05 from that in whole-wheat flour from artificially infected grain, it indicates that after inoculation, bran had biochemical compounds capable of significantly diminishing trichothecene production. It was investigated that DON levels were concentrated in white flour fractions 160 and 112 μm from naturally infected grains and in white flour fraction (residues) from artificially and naturally infected grains harvested later. The results obtained in this study could be further used for developing novel strategies aimed at limiting mycotoxin contamination in food and feed.

Relationship between environmental conditions,TRI5 gene expression and deoxynivalenol production in storedLentinula edodes infected withFusarium graminearum

This study made the first attempt to relate the production of deoxynivalenol (DON) to the expression ofTRI5 gene inFusarium graminearum as a function of interacting environmental factors (water activity (aw) (0.95-0.98), temperature (20-30 °C) and incubation time (7 day-28 day)), so as to investigate its production mechanisms inLentinula edodes. Changes in temperature, water activity and incubation time could significantly (P&lt;0.01) affect DON production andTRI5 gene expression. The highest DON concentration (793.5±27.4 μg/kg) andTRI5 gene expression (2−ΔΔCt=38.8±4.8) were observed when the cultures were incubated at 20 °C and 0.98 aw for 21 days. Multi-regression analysis was performed and nonlinear models based on polynomial equations were established to uncover the individual effects of temperature, water activity and incubation time as well as their interactions on DON production andTRI5 gene expression. The established model was further used to develop contour maps to predict the DON production andTRI5 gene expression in relation to storage conditions inL. edodes. Highly significant positive correlation between DON production and foldTRI5 gene expression (R=0.5534,P&lt;0.0001) was observed in this commodity. The production mechanisms of DON inL. edodes revealed in the present study will be beneficial for developing more effective targeted control strategies.

Impact of deoxynivalenol on rainbow trout: Growth performance, digestibility, key gene expression regulation and metabolism

The impact of deoxynivalenol (DON) on rainbow trout, Oncorhynchus mykiss, is mainly characterised by impaired growth performance and reduced feed intake, usually with the total absence of any visible clinical signs. Despite the high concentrations of DON in the present study (up to 11,412 ± 1141 μg kg−1), no clinical signs (except anorexia at the higher DON dosage) were observed, which confirms the difficulties of diagnosing DON ingestion. Compared to the control group, the proteolytic enzyme activities (pepsin, trypsin and chymotrypsin) in trout were altered by DON ingestion. However, it was not clear if the observed impact on digestive enzymes was due to the direct action of DON, or a consequence of the lower feed intake determined for DON-treated animals. The impact of DON on the abundance of specific measured mRNA transcripts was unexpected with higher expression levels for insulin-like growth factors, igf1 and igf2, which are directly related to elevated insulin levels in plasma. This can also in part be influenced by the trypsin activity and by npy, given its higher mRNA expression levels. The apparent digestibility of dry matter, protein and energy was not affected by dietary levels of DON, however, nutrient retention, protein, fat and energy retention were significantly affected in animals fed DON. Adenylate cyclase-activating polypeptide (PACAP) expression seems to play an important role in controlling feed intake in DON fed trout. In the present study, we have shown for the first time that DON is metabolized to DON-3-sulfate in trout. DON-3-sulfate is much less toxic than DON, which helps to explain the lack of clinical signs in fish fed DON. Being a novel metabolite identified in trout makes it a potential biomarker of DON exposure. Suppression of appetite due to DON contamination in feeds might be a defense mechanism in order to decrease the exposure of the animal to DON, therefore reducing the potential negative impacts of DON.

Aerobic De-Epoxydation of Trichothecene Mycotoxins by a Soil Bacterial Consortium Isolated Using In Situ Soil Enrichment.

Globally, the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are among the most widely distributed mycotoxins that contaminate small grain cereals. In this study, a bacterial consortium, PGC-3, with de-epoxydation activity was isolated from soil by an in situ soil enrichment method. Screening of 14 soil samples that were sprayed with DON revealed that 4 samples were able to biotransform DON into de-epoxydized DON (dE-DON). Among these, the PGC-3 consortium showed the highest and most stable activity to biotransform DON into dE-DON and NIV into dE-NIV. PGC-3 exhibited de-epoxydation activity at a wide range of pH (5–10) and temperatures (20–37 °C) values under aerobic conditions. Sequential subculturing with a continued exposure to DON substantially reduced the microbial population diversity of this consortium. Analyses of the 16S rDNA sequences indicated that PGC-3 comprised 10 bacterial genera. Among these, one species, Desulfitobacterium, showed a steady increase in relative abundance, from 0.03% to 1.55% (a 52-fold increase), as higher concentrations of DON were used in the subculture media, from 0 to 500 μg/mL. This study establishes the foundation to further develop bioactive agents that can detoxify trichothecene mycotoxins in cereals and enables for the characterization of detoxifying genes and their regulation.