Acute toxicity of vomitoxin (Deoxynivalenol) in broiler chickens

Update on the state of research to manage Fusarium head blight

Fusarium head blight (FHB) is one of the most devastating diseases of cereal crops, causing severe reduction in yield and quality of grain worldwide. In the United States, the major causal agent of FHB is the mycotoxigenic fungus, Fusarium graminearum. The contamination of grain with mycotoxins, including deoxynivalenol and zearalenone, is a particularly serious concern due to its impact on the health of humans and livestock. For the past few decades, multidisciplinary studies have been conducted on management strategies designed to reduce the losses caused by FHB. However, effective management is still challenging due to the emergence of fungicide-tolerant strains of F. graminearum and the lack of highly resistant wheat and barley cultivars. This review presents multidisciplinary approaches that incorporate advances in genomics, genetic-engineering, new fungicide chemistries, applied biocontrol, and consideration of the disease cycle for management of FHB.

Biomarkers of Deoxynivalenol Toxicity in Chickens with Special Emphasis on Metabolic and Welfare Parameters

Deoxynivalenol (DON), a trichothecene mycotoxin produced by Fusarium species, is the most widespread mycotoxin in poultry feed worldwide. Long term-exposure from low to moderate DON concentrations can produce alteration in growth performance and impairment of the health status of birds. To evaluate the efficacy of mycotoxin-detoxifying agent alleviating the toxic effects of DON, the most relevant biomarkers of toxicity of DON in chickens should be firstly determined. The specific biomarker of exposure of DON in chickens is DON-3 sulphate found in different biological matrices (plasma and excreta). Regarding the nonspecific biomarkers called also biomarkers of effect, the most relevant ones are the impairment of the productive parameters, the intestinal morphology (reduction of villus height) and the enlargement of the gizzard. Moreover, the biomarkers of effect related to physiology (decrease of blood proteins, triglycerides, hemoglobin, erythrocytes, and lymphocytes and the increase of alanine transaminase (ALT)), immunity (response to common vaccines and release of some proinflammatory cytokines) and welfare status of the birds (such as the increase of Thiobarbituric acid reactive substances (TBARS) and the stress index), has been reported. This review highlights the available information regarding both types of biomarkers of DON toxicity in chickens.

Potential contaminants and hazards in alternative chicken bedding materials and proposed guidance levels: a review

Bedding material or litter is an important requirement of meat chicken production which can influence bird welfare, health, and food safety. A substantial increase in demand and cost of chicken bedding has stimulated interest in alternative bedding sources worldwide. However, risks arising from the use of alternative bedding materials for raising meat chickens are currently unknown. Organic chemicals, elemental, and biological contaminants, as well as physical and management hazards need to be managed in litter to protect the health of chickens and consequently that of human consumers. This requires access to information on the transfer of contaminants from litter to food to inform risk profiles and assessments to guide litter risk management. In this review, contaminants and hazards of known and potential concern in alternative bedding are described and compared with existing standards for feed. The contaminants considered in this review include organic chemical contaminants (e.g., pesticides), elemental contaminants (e.g., arsenic, cadmium, and lead), biological contaminants (phytotoxins, mycotoxins, and microorganisms), physical hazards, and management hazards. Reference is made to scientific literature for acceptable levels of the above contaminants in chicken feed that can be used for guidance by those involved in selecting and using bedding materials.

The Effect of Low and High Dose Deoxynivalenol on Intestinal Morphology, Distribution, and Expression of Inflammatory Cytokines of Weaning Rabbits

Deoxynivalenol (DON) is a potential pathogenic factor to humans and animals, and intestinal tract is the primary target organ of DON. Data concerning the effects of DON on rabbits are scarce, especially for weaning rabbits. In this study, 45 weaning rabbits (35 d) were randomly and equally assigned into three groups. Group A was fed basic diet, while groups B and C were added DON at 0.5 mg/kg BW/d and 1.5 mg/kg BW/d, respectively, based on the basic diet. The experiment lasted for 24 days and the intestinal morphology, expression, and distribution of several cytokines in intestinal segments have been examined. The results indicated that ADG decreased while F/G increased significantly compared with the control group after DON added at 1.5 mg/kg BW/d. Some of the morphometric parameters (villi length, crypt depth, and goblet cells density) changed after DON was added. Meanwhile, the concentration as well as the expression levels of relative protein and mRNA of IL-1β, IL-2, IL-6, and IL-8 increased significantly. The immunohistochemistry results illustrated that the quantity and distribution of positive cells of inflammatory cytokines were changed after DON was added. In conclusion, the addition of DON damaged the intestinal morphology and changed the distribution and expression of inflammatory cytokines. The toxic effect depended on the dosage of DON.

Fusarium Molds and Mycotoxins: Potential Species-Specific Effects

This review summarizes the information on biochemical and biological activity of the main Fusarium mycotoxins, focusing on toxicological aspects in terms of species-specific effects. Both in vitro and in vivo studies have centered on the peculiarity of the responses to mycotoxins, demonstrating that toxicokinetics, bioavailability and the mechanisms of action of these substances vary depending on the species involved, but additional studies are needed to better understand the specific responses. The aim of this review is to summarize the toxicological responses of the main species affected by Fusarium mycotoxins.

Risks to human and animal health related to the presence of deoxynivalenol and its acetylated and modified forms in food and feed

Deoxynivalenol (DON) is a mycotoxin primarily produced by Fusarium fungi, occurring predominantly in cereal grains. Following the request of the European Commission, the CONTAM Panel assessed the risk to animal and human health related to DON, 3-acetyl-DON (3-Ac-DON), 15-acetyl-DON (15-Ac-DON) and DON-3-glucoside in food and feed. A total of 27,537, 13,892, 7,270 and 2,266 analytical data for DON, 3-Ac-DON, 15-Ac-DON and DON-3-glucoside, respectively, in food, feed and unprocessed grains collected from 2007 to 2014 were used. For human exposure, grains and grain-based products were main sources, whereas in farm and companion animals, cereal grains, cereal by-products and forage maize contributed most. DON is rapidly absorbed, distributed, and excreted. Since 3-Ac-DON and 15-Ac-DON are largely deacetylated and DON-3-glucoside cleaved in the intestines the same toxic effects as DON can be expected. The TDI of 1 μg/kg bw per day, that was established for DON based on reduced body weight gain in mice, was therefore used as a group-TDI for the sum of DON, 3-Ac-DON, 15-Ac-DON and DON-3-glucoside. In order to assess acute human health risk, epidemiological data from mycotoxicoses were assessed and a group-ARfD of 8 μg/kg bw per eating occasion was calculated. Estimates of acute dietary exposures were below this dose and did not raise a health concern in humans. The estimated mean chronic dietary exposure was above the group-TDI in infants, toddlers and other children, and at high exposure also in adolescents and adults, indicating a potential health concern. Based on estimated mean dietary concentrations in ruminants, poultry, rabbits, dogs and cats, most farmed fish species and horses, adverse effects are not expected. At the high dietary concentrations, there is a potential risk for chronic adverse effects in pigs and fish and for acute adverse effects in cats and farmed mink.

Potential natural exposure of endangered red-crowned crane (Grus japonensis) to mycotoxins aflatoxin B1, deoxynivalenol, zearalenone, T-2 toxin, and ochratoxin A

A survey was conducted to determine whether mycotoxins were present in the foods consumed by red-crowned cranes (Grus japonensis) in the Yancheng Biosphere Reserve, China. Collected in the reserve's core, buffer, and experimental zones during overwintering periods of 2013 to 2015, a total of 113 food samples were analyzed for aflatoxin B1, deoxynivalenol, zearalenone, T-2 toxin, and ochratoxin A using high performance liquid chromatography (HPLC). The contamination incidences vary among different zones and the mycotoxins levels of different food samples also presented disparity. Average mycotoxin concentration from rice grain was greater than that from other food types. Among mycotoxin-positive samples, 59.3% were simultaneously contaminated with more than one toxin. This study demonstrated for the first time that red-crowned cranes were exposed to mycotoxins in the Yancheng Biosphere Reserve and suggested that artificial wetlands could not be considered good habitats for the birds in this reserve, especially rice fields.

Revisión: Implicaciones toxicológicas y nutricionales de la toxina T-2 / Review: Toxicological and nutritional implications of T-2 toxin

Trichothecenes are mycotoxins produced by species of the genus Fusarium. These toxins are associated with health problems in humans and animals. The most common trichothecenes in cereals are deoxynivalenol, HT-2 toxin, diacetoxyscirpenol, nivalenol, neosolaniol and T-2 toxin; the latter is the most widely studied because it is easy to produce in the laboratory. The effects of T-2 toxicosis include dermatonecrosis, reduced body weight and efficiency of food utilization, severe diarrhoea, haemorrhage, necrosis of the upper alimentary tract, anaemia, immuno suppression ; and in birds, poor feathering. This paper reviews the latest information about the occurrence, chemical characteristics, toxicity, metabolic alterations, biotransformation and detoxifi cation methods of the T-2 toxin.

Adsorption of ochratoxin A, deoxynivalenol and zearalenonein vitro at different pH and adsorbents

The adsorption of standards of 100 µg/kg Ochratoxin A (OTA), 30 mg/kg Deoxynivalenol (DON) and 30 mg/kg Zearalenone (ZEA) from 2.5 ml phosphate buffer (pH 3.0 and pH 7.0) and pure destilled water were studiedin vitro after addition of 0.1, 0.25, 0.5, 1.0 and 2.5 % (w/v) activated charcoal and four adsorbents (A I-A IV). Adsorbent A I was 1.0, 2.5 and 5.0 % modified yeast cell wall+vitamin mixture+plant oil refined. A II was modified yeast cell wall. A III was bentonite+enzymes+modified yeast cell wall+vitamin E+trace elements. A IV was bentonite. The adsorption for OTA and ZEA were 100 % by 0.1 % activated charcoal, but DON adsorption ranged from 47 to 99 % depending on the concentration of charcoal and pH value. However, adsorption of DON by 0.5, 1.0 and 2.5 % charcoal did not differ significantly by different pH buffers. Adsorption of OTA by A I, A II and A III (1.0 and 2.5 %) was higher in pH 7.0 buffer and pure destilled water compared to pH 3.0 buffer. A IV and 5.0 % A II showed an opposite trend. However, adsorption of OTA was by A II>A III>A IV (at pH 7.0 and water). The overall means of adsorption were higher by A II>A III>A IV>A I. Generally, the adsorption ranged from 15 to 60 % depending on kind and concentration of adsorbents and pH values. DON adsorption (30, 16 and 5 mg/kg) was not affected by A I, A II, A III and A IV. Adsorption of ZEA was highest by A I, and the lowest by A III. The means of adsorption at different pH were by A I>A II>A IV (2.5 and 5.0 %)>A III. The overall means show the same trend. Generally, the adsorption ranged from 13 to 57 %.

Mycotoxin-contaminated diets and deactivating compound in laying hens: 1. effects on performance characteristics and relative organ weight

The current experiment was conducted to determine the effect of mycotoxin-contaminated diets with aflatoxin (AFLA) and deoxynivalenol (DON) and dietary inclusion of deactivation compound on layer hen performance during a 10-wk trial. The experimental design consisted of a 4 × 2 factorial with 4 toxin levels: control, low (0.5 mg/kg AFLA + 1.0 mg/kg DON), medium (1.5 mg/kg AFLA + 1.5 mg/kg DON), and high (2.0 mg/kg AFLA + 2.0 mg/kg DON) with or without the inclusion of deactivation compound. Three hundred eighty-four 25-wk-old laying hens were randomly assigned to 1 of the 8 treatment groups. Birds were fed contaminated diets for a 6-wk phase of toxin administration followed by a 4-wk recovery phase, when all birds were fed mycotoxin-free diets. Twelve hens from each treatment were subjected to necropsy following each phase. Relative liver and kidney weights were increased (P < 0.05) at the medium and high toxin levels following the toxin phase, but the deactivation compound reduced (P < 0.05) relative liver and kidney weights following the recovery period. The high toxin level decreased (P < 0.05) feed consumption and egg production during the toxin period, whereas the deactivation compound increased (P < 0.05) egg production during the first 2 wk of the toxin phase. Egg weights were reduced (P < 0.05) in hens fed medium and high levels of toxin. An interaction existed between toxin level and deactivation compound inclusion with regard to feed conversion (g of feed/g of egg). High inclusion level of toxins increased feed conversion compared with the control diet, whereas deactivation compound inclusion reduced feed conversion to a level comparable with the control. These data indicate that deactivation compound can reduce or eliminate adverse effects of mycotoxicoses in peak-performing laying hens.

Deoxynivalenol and its toxicity

Deoxynivalenol (DON) is one of several mycotoxins produced by certain Fusarium species that frequently infect corn, wheat, oats, barley, rice, and other grains in the field or during storage. The exposure risk to human is directly through foods of plant origin (cereal grains) or indirectly through foods of animal origin (kidney, liver, milk, eggs). It has been detected in buckwheat, popcorn, sorgum, triticale, and other food products including flour, bread, breakfast cereals, noodles, infant foods, pancakes, malt and beer. DON affects animal and human health causing acute temporary nausea, vomiting, diarrhea, abdominal pain, headache, dizziness, and fever. This review briefly summarizes toxicities of this mycotoxin as well as effects on reproduction and their antagonistic and synergic actions.

Deoxynivalenol: toxicology and potential effects on humans

Deoxynivalenol (DON) is a mycotoxin that commonly contaminates cereal-based foods worldwide. At the molecular level, DON disrupts normal cell function by inhibiting protein synthesis via binding to the ribosome and by activating critical cellular kinases involved in signal transduction related to proliferation, differentiation, and apoptosis. Relative to toxicity, there are marked species differences, with the pig being most sensitive to DON, followed by rodent > dog > cat > poultry > ruminants. The physiologic parameter that is most sensitive to low-level DON exposure is the emetic response, with as little as 0.05 to 0.1 mg/kg body weight (bw) inducing vomiting in swine and dogs. Chinese epidemiological studies suggest that DON may also produce emetic effects in humans. With respect to chronic effects, growth (anorexia and decreased nutritional efficiency), immune function, (enhancement and suppression), and reproduction (reduced litter size) are also adversely affected by DON in animals, whereas incidence of neoplasia is not affected. When hazard evaluations were conducted using existing chronic toxicity data and standard safety factors employed for anthropogenic additives/contaminants in foods, tolerable daily intakes (TDIs) ranging from 1 to 5 microg/kg bw have been generated. Given that critical data gaps still exist regarding the potential health effects of DON, additional research is needed to improve capacity for assessing adverse health effects of this mycotoxin. Critical areas for future DON research include molecular mechanisms underlying toxicity, sensitivity of human cells/tissues relative to other species, emetic effects in primates, epidemiological association with gastroenteritis and chronic disease in humans, and surveillance in cereal crops worldwide.

Effects of deoxynivalenol on general performance and electrophysiological properties of intestinal mucosa of broiler chickens

A feeding trial was conducted to evaluate the effects of diets contaminated with deoxynivalenol (DON on the performance of broilers and on the electro-physiological parameters of the gut. The control group was fed the starter and finisher diets without addition of DON. Another group of broilers was fed the starter and finisher diets with 10 mg/kg DON, whereas another group was fed the DON-contaminated diets supplemented with a microbial feed additive (Eubacterium sp.). The diets were provided ad libitum for 6 wk. DON had no effect (P > 0.05) on feed consumption, feed conversion, or body weight. The effect of DON on the electrophysiological parameters of the jejunum was studied in vitro using isolated gut mucosa in Ussing chambers. At the end of the feeding period, 7 birds from each group were killed, and the basal and glucose stimulated transmural potential difference (PD), short-circuit current (Isc), and electrical resistance (R) were measured in the isolated gut mucosa to characterize the electrical properties of the gut. The transmural PD did not differ (P > 0.05) among groups. The tissue resistance was greater (P < 0.05) in birds receiving DON and the microbial feed additive than in the controls and DON group. Addition of D-glucose on the luminal side of the isolated mucosa increased (P < 0.05) Isc in the control and DON-probiotic (Eubacterium sp.; PB) groups, whereas it decreased (P < 0.05) in the DON group indicating that the glucose-induced Isc was altered by DON. Addition of the eubacteria to the DON contaminated feed of the broilers led to electrophysiological properties in the gut that were comparable with those of the control group. It could be concluded that 10 mg/kg DON in the diet impaired the Na(+)-D-glucose cotransport in the jejunum of broilers. In the absence of clinical signs, and without impaired performance, DON appeared to alter the gut function of broilers. The addition of Eubacterium sp. may be useful in counteracting the toxic effects of DON on intestinal glucose transport.

Effects of graded levels ofFusarium-toxin-contaminated wheat in Pekin duck diets on performance, health and metabolism of deoxynivalenol and zearalenone

1. Diets with increasing proportions of Fusarium-toxin-contaminated wheat were fed to Pekin ducks for 49 d in order to titrate the lowest effect level. Dietary deoxynivalenol (DON) and zearalenone (ZON) concentrations were successively increased up to 6 to 7 mg/kg and 0.05 to 0.06 mg/kg, respectively. 2. Feed intake, live weight gain and feed to gain ratio were not influenced by dietary treatment. 3. Gross macroscopic inspection of the upper digestive tract did not reveal any signs of irritation, inflammation or other pathological changes. The weight of the bursa of Fabricius, relative to live weight, decreased in a dose-related fashion. Activities of glutamate dehydrogenase and gamma-glutamyl-transferase in serum were either unaffected or inconsistently affected by dietary treatments. 4. Concentrations of DON and of its de-epoxydised metabolite in plasma and bile were lower than the detection limits of 6 and 16 ng/ml, respectively, of the applied high performance liquid chromatography (HPLC) method. 5. ZON or its metabolites were not detectable in plasma and livers (detection limits of the HPLC method were 1, 0.5 and 5 ng/g for ZON, alpha-zearalenol (alpha-ZOL) and beta-zearalenol (beta-ZOL), respectively). Concentrations of ZON, alpha-ZOL and beta-ZOL in bile increased linearly with dietary ZON concentration. The mean proportions of ZON, alpha-ZOL and beta-ZOL of the sum of all three metabolites were 80, 16 and 4%, respectively. 6. Taken together, it can be concluded that dietary DON and ZON concentrations up to 6 and 0.06 mg/kg, respectively, did not adversely affect performance and health of growing Pekin ducks.

Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on production and metabolism in broilers

Three hundred sixty, 1-d-old male broiler chicks were fed diets containing grains naturally contaminated with Fusarium mycotoxins for 56 d. The four diets included control (0.14 mg/kg deoxynivalenol, 18 mg/ kg fusaric acid, < 0.1 mg/kg zearalenone), low level of contaminated grains (4.7 mg/kg deoxynivalenol, 20.6 mg/kg fusaric acid, 0.2 mg/kg zearalenone), and high level of contaminated grains without (8.2 mg/kg deoxynivalenol, 20.3 mg/kg fusaric acid, 0.56 mg/kg zearalenone) and with (9.7 mg/kg deoxynivalenol, 21.6 mg/kg fusaric acid, 0.8 mg/kg zearalenone) 0.2% esterified-glucomannan polymer derived from Saccharomyces cerevisiae1026 (E-GM). Body weight gain and feed consumption responded in a significant quadratic fashion to the inclusion of contaminated grains during the finisher period. Efficiency of feed utilization, however, was not affected by diets. The feeding of contaminated grains in the finisher period also caused significant linear increases in blood erythrocyte count and serum uric acid concentration and a significant linear decline in the serum lipase activity. Dietary inclusion of contaminated grains resulted in a significant quadratic effect on serum albumin and y-glutamyltransferase activity. Blood hemoglobin and biliary IgA concentrations, however, responded in significant linear and quadratic fashions. Supplementation of E-GM counteracted most of the blood parameter alterations caused by the Fusarium mycotoxin-contaminated grains and reduced breast muscle redness. It was concluded that broiler chickens may be susceptible to Fusarium mycotoxicoses when naturally contaminated grains are fed containing a combination of mycotoxins.

Absorption and metabolism of nivalenol in pigs

The absorption and metabolism of nivalenol (NIV) were studied in pigs fed 0.05 mg NIV/kg BW, twice daily. Blood samples were taken during the first and third day, through catheters in the hepatic portal vein and peripheral mesenteric artery. Nivalenol was detected in most of the earliest blood samples, taken twenty minutes after the start of feeding. During 7.5 hrs after feeding, 11-43% of the NIV dose was absorbed. The systemic peak concentrations were 3-6 ng NIV/ml, mostly occurring 2.5-4.5 h after feeding. Sixteen hours after feeding, NIV was still being absorbed from the intestine, and the systemic concentrations were 1-3 ng NIV/ml. Nivalenol was mainly excreted in faeces, which contained concentrations up to 3.2 mg NIV/kg. No metabolites of NIV were found in plasma, urine, and faeces, either as glucuronic acid or sulphate conjugates, or as de-epoxy-NIV, indicating a lack of metabolism. The feeding of NIV did not cause feed refusal, and measured clinical plasma parameters were within the normal ranges.

Effect of dietary T-2 toxin on biogenic monoamines in discrete areas of the rat brain

Acute T-2 toxin treatments alter biogenic monoamine concentrations in the brain; however, these perturbations have not been well documented or demonstrated in feeding trials. In this study, the effect of dietary T-2 toxin on regional brain concentrations of biogenic monoamines and their metabolites was investigated in male rats fed a semi-synthetic diet containing 0, 2.5 or 10 ppm T-2 toxin for either 7 or 14 days. Reduction in feed consumption, feed efficiency and weight gain was observed in rats fed either 2.5 or 10 ppm T-2 toxin. This effect was transient in animals fed the 10 ppm T-2 toxin diet, with feed consumption, feed efficiency and weight gain improving significantly during wk 2. T-2 toxin affected brain biogenic monoamine concentrations. In the nucleus raphe magnus, serotonin, 5-hydroxy-3-indoleacetic acid and norepinephrine increased in a dose-dependent manner, and dopamine increased transiently. In the substantia nigra of rats fed 10 ppm T-2, epinephrine increased after 7 days and norepinephrine decreased after 14 days, when compared with controls. Dihydroxyphenylacetic acid concentrations in the paraventricular nucleus and medial forebrain bundle were lower in T-2 toxin-treated rats than in control animals. The observed effects of T-2 toxin on brain monoamines and the resulting neurochemical imbalance may account for the physiological manifestation of trichothecene intoxication.

Influence of subchronic exposure to low dietary deoxynivalenol, a trichothecene mycotoxin, on intestinal absorption of nutrients in mice

During a 6-wk feeding trial, effects of low dietary deoxynivalenol (DON; 0, 0.1, 1 and 10 ppm) on food consumption and weight gain were investigated in male mice. Food intake was similar in all four dietary groups. Weight gain in the group receiving 10 ppm DON was significantly (P less than 0.01) reduced. At the end of the feeding period, test animals were sacrificed and absorption of water, D-glucose, L-leucine, L-tryptophan, 5-methyltetrahydrofolic acid and iron was measured in isolated perfused jejunal segments in vitro. No effects were observed on absorption of water, leucine, tryptophan and iron. However, at a dietary DON concentration of 10 ppm, a slightly but significantly (P less than 0.05) reduced transfer of glucose was measured. Furthermore, transfer as well as tissue accumulation of 5-methyltetrahydrofolic acid in the jejunal segment were both significantly decreased up to 50%. Heavy metal and trace element content was determined in liver, kidney and small intestine. Manganese and molybdenum content in liver tissue was reduced with a DON concentration of 10 ppm in the diet. The findings indicate that subchronic ingestion of DON, in concentrations occurring in contaminated food and feed, results in an impairment of intestinal transfer and uptake of nutrients such as glucose and 5-methyltetrahydrofolic acid.

Comparative toxicity of scirpentriol and its acetylated derivatives

Scirpentriol (STO) and its seven acetylated derivatives, 3-, 4- and 15-monoacetoxyscirpenol (MAS), 3,4-, 3,15-, and 4,15-diacetoxyscirpenol (DAS), and 3,4,15-triacetoxyscirpenol (TAS) were compared for their acute oral lethality in broiler chicks, lethality in brine shrimp, and dermal toxicity in guinea pigs. Of the eight toxins, 4,15-DAS was the most toxic in the three assays, 3-MAS was the least toxic in brine shrimp and dermal assays, and 3,4-DAS was the least toxic in the chick assay. There was a difference of about a 100-fold and 20-fold, respectively, between 4,15-DAS and 3-MAS in dermal toxicity and brine-shrimp toxicity, as well as a difference of more than 16-fold between 4,15-DAS and 3,4-DAS in chick toxicity. In general, a free hydroxy group at the 3-position was a primary determinant of toxicity. Toxicity in the scirpenol family did not follow precisely the pattern reported earlier for the T-2 toxin family of trichothecene toxins, in which a decrease in the number of acyl groups was accompanied by a decrease in toxicity. At necropsy, the predominant sign in chicks was petechial hemorrhaging, primarily in the gastrointestinal tract and in the vascular beds of the beaks and the toe nails. The 4,15-DAS and 15-MAS were about 3 times more toxic in chicks than aflatoxin. All members of the scirpenol family of trichothecene mycotoxins appeared sufficiently toxic to warrant attention whenever field outbreaks occur. Apparently, brine shrimp and dermal assays are successful predictors of chick lethality by the more toxic trichothecenes and are less suitable for predicting the activity of the less toxic trichothecenes.

Response of growing Leghorn chicks to deoxynivalenol-contaminated wheat

Effects of feeding a deoxynivalenol (DON)-contaminated wheat diet containing 18 mg DON/kg were determined in male Leghorn chicks from 1 day to 12 wk of age. The data show that body weights were not adversely affected by the inclusion of the contaminated wheat in the diet. Relative gizzard weights were increased in the chicks receiving the contaminated wheat diet. Consistent significant differences were not observed for relative weights of other organs, serum chemistry, or minerals. A significant decrease in hemoglobin at 4 wk of age occurred, but this effect was transitory in nature; it was no longer present at 8 or 12 wk of age.

Influence of ochratoxin A and deoxynivalenol on growing broiler chicks

The effects of feeding diets containing ochratoxin A (OA) (2.0 mg/kg) and deoxynivalenol (DON) (16 mg/kg) singly and in combination were characterized in male broiler chicks from 1 to 3 wk of age. Body weight gains and efficiency of feed utilization were significantly reduced by feeding OA singly, DON singly, and the OA/DON combination. Increased relative liver, kidney, and proventriculus weights were observed in the OA and OA-DON groups and blood urea nitrogen (BUN) was increased in the DON group. Serum uric acid, creatinine, and triglycerides were significantly elevated, and total protein, albumin, cholesterol, and aspartate amino transferase (AST) activity were decreased in the OA group. Histopathological examination of the liver, kidney, spleen, proventriculus, gizzard, and bursa revealed that lesions were confined primarily to mild hepatocellular degeneration, with milk diffuse lipidosis of the liver and mild swelling of the renal tubular epithelium of the OA and OA/DON combination groups. For a few parameters such as efficiency of utilization and relative liver, gizzard, and spleen weights. OA and DON appear to interact additively. However, many of the parameters such as body weights, body weight gains, BUN, total protein, and AST show significant interactions that can best be described as less than additive or in some cases antagonistic.

Effects of feeding deoxynivalenol (DON, vomitoxin)-contaminated wheat to female White Leghorn chickens from day old through egg production

White Leghorn chickens one day of age were fed starter and grower diets containing either a control (noncontaminated) wheat diet or a naturally contaminated deoxynivalenol (DON) wheat diet (18 mg DON/kg) from 1 day of age to the onset of egg production. The hens were then placed on their respective layer diets of control wheat or DON-contaminated wheat (18 mg DON/kg) for six 28-day egg production periods. Feeding the DON-contaminated diet did not significantly influence body weights during the growing or the laying phases. Overall, hen-day egg production and egg weights were significantly higher for hens receiving the DON diet. Feeding DON contaminated wheat caused no significant changes in percent shell, albumen height, percent fertility, percent hatch of fertile eggs, percent hatch of eggs set, or weight of chicks at hatch. There were slight, although significant, changes in shell weight and shell thickness and in some serum chemistry values. There were no significant differences in the hematology parameters measured or in prothrombin times. None of the eggs collected from hens fed the control and the DON-contaminated wheat diet contained detectable quantities of DON. Microscopic examination of sections of the liver, kidney, and proventriculus of control and treated hens revealed no unusual histopathology. The results indicate that feeding DON at relatively high levels beginning at 1 day of age and continuing through six egg production periods had only slight effects on the parameters measured.

Decreased feed consumption and body-weight gain in the B6C3F1 mouse after dietary exposure to 15-acetyldeoxynivalenol

15-Acetyldeoxynivalenol (15-ADON), a biosynthetic precursor of deoxynivalenol (DON), was extracted from rice cultures of Fusarium graminearum R6576 and purified. Growing female B6C3F1 mice were fed semi-purified diets containing 0, 0.5, 2.0 and 5.0 ppm 15-ADON over 56 days and assessed for effects on feed intake, body-weight gain, terminal organ weights and blood clotting function. A significant reduction in feed intake was observed at the 5.0-ppm level after 44 days, whereas reduced rates of weight gain were found to occur at the 5.0-ppm level after only 16 days. Terminal liver, kidney and spleen weights were significantly lower in mice consuming the 5.0-ppm diet when compared with controls. Dietary 15-ADON at the 0.5- and 2.0-ppm levels did not show significant effects on weight gain, feed intake or organ weights. Although mice treated with 15-ADON had significantly decreased bleeding times, other measurements of clotting function indicated no differences between the control and treated groups. Results indicated that 15-ADON was only slightly less toxic than DON and that chronic manifestations of dietary 15-ADON were similar to those found previously for DON. Future risk assessments for DON should therefore include consideration of 15-ADON occurrence and toxicity.

Individual and combined effects of aflatoxin and deoxynivalenol (DON, vomitoxin) in broiler chickens

The individual and combined effects of aflatoxin and deoxynivalenol (DON) were evaluated in young broiler chickens (Hubbard X Hubbard). The experimental design was a 2 X 2 factorial with treatments of 0 and 2.5 micrograms of aflatoxin/g of feed (ppm) and 0 and 16 micrograms of DON/g of feed. The broilers were maintained on these dietary treatments from hatching to 3 weeks of age in electrically heated batteries with feed and water available ad libitum. The aflatoxin treatment significantly (P less than .05) decreased body weight; weight gain; increased the relative weight of the spleen, liver, and kidney; induced hepatic hyperlipemia; decreased activity of lactic dehydrogenase; and decreased serum levels of protein, albumin, and phosphorus. The toxicity of DON was expressed through reduced growth rate, increased feed conversion; increased relative weight of the gizzard, anemia, decreased activity of lactic dehydrogenase, and decreased serum triglycerides. The interaction between aflatoxin and DON was characterized by reduced growth rates; increased feed conversion, increased relative weight of the proventriculus, gizzard, spleen, liver, and kidney, anemia, hepatic hyperlipemia, decreased activity of alkaline phosphatase, glutamic oxalacetic transaminase, and lactic dehydrogenase, and decreased serum levels of protein, albumin, uric acid, cholesterol, triglycerides, and calcium. These data demonstrate that both aflatoxin and DON can limit broiler performance and adversely effect broiler health. The effects of the combination of aflatoxin and DON on broiler performance and health was more severe than the individual effects of these mycotoxins; however, the interaction was not severe enough to represent toxic synergy and can best be characterized as additive toxicity.

Evaluation of purified 4-deoxynivalenol (vomitoxin) for unscheduled DNA synthesis in the primary rat hepatocyte-DNA repair assay

Primary cultures of rat hepatocytes were used to determine unscheduled DNA synthesis (UDS) and cytotoxicity of purified 4-deoxynivalenol (vomitoxin), a trichothecene mycotoxin produced on cereal grains by fungi of the genus Fusarium. Nontoxic and toxic doses of deoxynivalenol, 0.1 to 1000 micrograms/ml, did not significantly increase UDS as measured by net grains per nucleus, net grains per nuclear area or percentage of cells incorporating greater than or equal to 5, 6, 10 or 20 grains per nucleus. Evidence of cytotoxicity, manifested as a reduction in cell number in autoradiographs, pyknotic nuclei or vacuolated cytoplasm, was observed in hepatocytes treated with deoxynivalenol concentrations of 5 micrograms/ml and above. These findings suggest that the cellular toxicity of deoxynivalenol may not be mediated by a DNA-damaging event in cultured hepatocytes. An increased percentage of large-sized nuclei was also found to be associated with toxic doses of deoxynivalenol as well as 2-acetylaminofluorene used as the positive control.

Effects of feeding white Leghorn hens diets that contain deoxynivalenol (vomitoxin)-contaminated wheat

A short-term (10 weeks, Experiment 1) and a long-term experiment (24 weeks, Experiment 2) were done to determine effects of incorporating either white winter wheat, naturally contaminated with 1 mg deoxynivalenol (DON)/kg, or spring wheats, containing up to 6.5 mg DON/kg, into the diets of White Leghorn hens. Based on chemical analysis, the diets in Experiment 1 contained less than .05 to .7 mg DON/kg, while those in Experiment 2 contained from .2 to 4.9 mg/kg. Incorporation of winter or spring wheat in the experimental diets had no effect (P greater than .05) on feed intake and efficiency, egg production and yield, the number of soft shell and cracked eggs observed in the laying house, body weight at the completion of the experimental period, fertility, hatchability of fertile eggs, and the proportion of malformed embryos and pips. In addition, presence of DON-contaminated wheat did not influence (P greater than .05) the organ weight to body weight ratio for a randomly selected sample of hens necropsied at the completion of each experiment. There was little evidence of lesions in the oral cavity, esophagus, proventriculus and gizzard, hemorrhaging in the viscera or skeletal muscles, or of changes in the appearance of spleen, heart, and kidney. However, the livers from DON hens were fatty in appearance. Furthermore, vomiting (emesis), diarrhea, or changes in behaviour were not apparent and mortality, normally very low, was not increased during either experiment. Inverse linear relationships were obtained in Experiment 1 between dietary DON concentrations and egg weight (P less than .05), shell weight and thickness (P less than .01), and percent shell (P less than .05). Although egg and shell variables measured in Experiment 2 were not significantly influenced (P greater than .05) by DON treatment, trends towards lower values with higher dietary DON levels were evident. Egg specific gravity, nondestructive deformation, and quasistatic compression fracture strength of the egg's shell were not influenced (P greater than .05) by dietary DON levels. The results from these experiments indicate that laying hens can tolerate diets containing up to 5 mg DON/kg from white winter or spring wheat for extended periods of time without serious adverse effects on health and productivity.

Production of zearalenone, T-2 toxin, and deoxynivalenol by Fusarium spp. isolated from plant materials grown in North Carolina

Fusarium spp. isolated from plant materials grown in the hot, humid climate of North Carolina were tested for production of mycotoxins. Isolates of F. acuminatum, F. graminearum, F. moniliforme, F. oxysporum, and F. solani produced zearalenone while isolates of F. equiseti and F. graminearum produced T-2 toxin and deoxynivalenol, respectively. This is the first report of zearalenone production by F. solani. The toxins were identified by capillary gas chromatography-mass spectrometry. These findings suggest that there are toxigenic strains of Fusarium indigenous to the warmer regions of the USA and that fasariotoxicoses of animals in this region are not necessarily the result of importing toxic grains from the cooler, upper midwestern USA.

The tolerance of White Leghorn and broiler chicks, and turkey poults to diets that contained deoxynivalenol (vomitoxin)-contaminated wheat

Three experiments were done to determine the effects of giving White Leghorn chickens, broiler chickens, and turkey poults diets that contained white winter or spring wheat contaminated with 4-deoxynivalenol (DON). Diets that contained .35 and .7 mg DON/kg from winter wheat did not (P greater than .05) influence feed intake, body weight gain, feed/gain ratio, and organ weight/body weight ratios of Leghorn and broiler chickens, and poults when fed between 7 and 21 days in Experiment 1. Dietary DON levels up to 4.6 mg/kg increased the feed intakes (P less than .01) and daily body weight gains (P less than .05) of Leghorn chickens between 7 and 35 days of age in Experiment 2 but had little effect (P greater than .05) on these variables for broiler chickens between 7 and 52 days of age in Experiment 3. Within Experiments 2 and 3, feed/gain ratios and organ weight/body weight ratios were similar among the Leghorn and broiler chickens, respectively. The dressing percent and chilled carcass weights of eviscerated broiler chickens were not affected (P greater than .05) by DON in the diets of Experiment 3. Mortality was low (less than 3.3%) for the three experiments and necropsy examination indicated that the birds died from several causes unrelated to the dietary treatment. There was no evidence of emesis during the experiments or of overt changes in the appearance of the oral cavity, heart, liver, spleen, kidney, proventriculus, gizzard, and intestines of a random sample of birds killed by carbon dioxide asphyxiation and necropsied. Differences occurred between the analyzed and calculated DON contents of the experimental diets; possible reasons for these differences are discussed. The results of these experiments indicate that young chickens and turkey poults can tolerate diets that contain DON up to at least 5 mg/kg from white winter or spring wheat.

Inhibition of bovine platelet function by T-2 toxin, HT-2 toxin, diacetoxyscirpenol and deoxynivalenol

The aggregation of bovine platelets suspended in homologous plasma is inhibited in the presence of T-2 toxin, HT-2 toxin, diacetoxyscirpenol (DAS) or deoxynivalenol (DON) when either collagen or ADP is used as the stimulatory agent for aggregation. For each of the mycotoxins the degree of inhibition is dependent on the amount of trichothecene present in the platelet suspension but is not dependent on the time of exposure of the platelets to the toxin. For both ADP- and collagen-stimulated platelets, the order of potency of inhibition is T-2 toxin greater than HT-2 toxin greater than DAS greater than DON. A significant (P less than 0.01) dose-dependent decrease was also observed in the amount of the thromboxane B2 released from collagen-stimulated platelets in the presence of each of the mycotoxins.

Method for detecting production of zearalenone, zearalenol, T-2 toxin, and deoxynivalenol by Fusarium isolates

Three methods for detecting toxigenic fusaria in culture were compared by using known producers of zearalenone, zearalenol, T-2 toxin, and deoxynivalenol. Moist, autoclaved rice cultures of known toxigenic isolates grown in 20-ml tubes yielded oily extracts containing compounds which interfered with qualitative and quantitative analysis for the mycotoxins. Vermiculite moistened with nutrient broth in 20-ml tubes yielded a much cleaner extract. Growing the fungi on a liquid medium required a shorter incubation period, but yields of T-2 toxin and deoxynivalenol were low and variable, and the method required greater space in the incubator. Screening of the extracts by thin-layer chromatography with colorimetric spray reagents to detect the presence of these toxins permitted reduction in the number of extracts quantified by the more lengthy gas-liquid chromatographic method. Culturing in nutrient broth on vermiculite in tubes coupled to a qualitative screen before quantitation proved to be a convenient, inexpensive, and relatively rapid method that enabled reliable screening of a large number of Fusarium isolates for toxin production as compared with prior methods.

Liver lipid levels in White Leghorn hens fed diets that contained wheat contaminated by deoxynivalenol (vomitoxin)

Three genotypes of White Leghorn hens were fed diets containing either clean wheat (less than .02 ppm deoxynivalenol in diet) or deoxynivalenol (vomitoxin) contaminated wheat (.35 or .70 ppm deoxynivalenol in diet) for 86 or 135 days. Lipid analyses indicated that the percent total lipid and the triglyceride content of livers from birds receiving the vomitoxin contaminated diets were significantly higher than for birds receiving the clean diet. However, the livers of birds receiving the .35 ppm diet had the highest percent total lipid and triglycerides. Livers from control birds contained 11.5% total lipid with 420 mg triglyceride per liver; livers from the .35 ppm birds had 16.7% total lipid, 785 mg triglyceride; livers from the .70 ppm birds had 13.4% total lipid, 548 mg triglyceride. Liver phospholipid content did not appear to be affected by the deoxynivalenol content of the diet. Both genotype and level of vomitoxin in the diet significantly affected liver cholesterol levels.

High tolerance of broilers to vomitoxin from corn infected with Fusarium graminearum

Corn purposely infected with Fusarium graminearum was found to contain 800 to 900 mg vomitoxin/kg. Contaminated corn was substituted for control corn at 0, 6, 12, 18, and 24% in a corn-soybean meal ration. Broiler cockerels were given each experimental diet from 6 to 11 days of age; then sample groups were necropsied. Remaining birds were subsequently offered commercial starter for 2 days and sample groups again necropsied. Growth and diet consumption were not significantly reduced until contaminated corn exceeded 12% of the ration (116 mg vomitoxin/kg). Alertness, coordination, and feathering appeared normal regardless of treatment. Birds that received contaminated corn exhibited plaques in the mouth and gizzard erosions proportional to the level of substitution. All lesions were generally restricted to the epithelial layer and no liver or kidney involvement could be demonstrated. A short return to uncontaminated feed eliminated most lesions. Fowl appear to be considerably more tolerant of vomitoxin than swine.