Diaplacentar deoxynivalenol intoxication in porcine fetuses. Are histomorphological and immunohistochemical investigations at the 70th day of gestation a helpful diagnostic tool?

Doctor of Philosophy / Department of Animal Sciences and Industry / Duane L. Davis / Jim L. Nelssen / A total of 188 sows and their litters were used in 2 experiments to evaluate methods to induce estrus and ovulation in lactating sows and effects on pig growth. In Exp. 1, an altered suckling method (ALT) was designed to combine split-weaning and intermittent suckling as a means to reduce the suckling stimulus in primi- and multiparous sows during the last week of lactation (d 18 to 25). The ALT sows were also removed for daily boar exposure. The ALT treatment produced lactational estrus in 75% and 95% of primiparous and multiparous sows, respectively. The ALT sows were in estrus earlier (P < 0.01) than controls post-farrowing, with no effect on subsequent reproductive performance. From d 18 to 32, the ALT treatment benefited (P < 0.01) growth of lightweight pigs but decreased (P < 0.01) BW gain of heavyweight pigs, resulting in overall similar growth. However, variation in BW was reduced (P < 0.01) by 50% for ALT litters. In Exp. 2, varying suckling reduction strategies were applied to boar-exposed lactating sows. Overall, 76% of sows in suckling reduction treatments expressed estrus in lactation. Split-weaned and ALT sows performed reproductively similar to controls, whereas sows with daily litter separation or a single 24 h litter removal tended (P < 0.10) to have reduced conception rates versus controls or split-weaned sows. Reduced suckling treatments differed in their ability to induce lactational estrus and impact on pig BW gain immediately post-weaning. However, no evidence was found of benefit for pig growth to market weight or litter BW variation. Four additional experiments using 902 nursery pigs were conducted to test the efficacy of potential detoxifying agents against deoxynivalenol (DON) in swine diets. The effects of DON were not offset by adding an algae-modified montmorillonite clay nor by a proprietary blend of preservatives and clays. However, hydrothermally treating DON-contaminated diets with sodium metabisulfite modified the structure of DON to a non-toxic DON-sulfonate adduct and restored nursery pig growth via improved (P < 0.05) ADG, ADFI and G:F.

Increased interest in value-added traits of soft winter wheat (SWW; Triticum aestivum L.), such as white-seed coat and gluten strength, has resulted from economic incentives for these traits. The first objective of this study was to determine whether differences existed between red- and white- seeded progeny of 17 populations. When abiotic and biotic stresses were negligible, significant differences were not detected between red- and white-seeded progeny, except for yield: red-seeded progeny had a significantly higher yield than the white-seeded progeny. However, when abiotic and biotic stresses were larger, the yield of white-seeded progeny was not significantly different from red-seeded progeny and the white-seeded progeny accumulated a significantly greater amount of deoxynivalenol (DON) than red-seeded progeny. Therefore, Kentucky producers should be cautious when considering production of white-seeded cultivars. The second objective of this study was to determine whether early- or late- generation selection for white-seeded progeny produced a higher frequency of superior white-seeded lines. Three selection methods were studied. Late-generation bulk selection produced a significantly lower frequency of superior white-seeded lines (1.7%) than single seed descent (SSD; 13.9%); the early-generation bulk (9.6%) did not differ statistically from either method. Although SSD produced the most superior lines, the utility of SSD breeding will have to be assessed by SWW breeders to justify additional labor and space requirements. The final objective was to determine whether early-generation selection of wheat quality, as determined by wheat meal-based assays, was effective. A cross between a strong gluten soft red winter and a weak gluten soft white winter wheat was examined. Significant correlations and regressions between wheat meal assays and flour-based assays were found. High heritability and realized genetic gains were also observed. Therefore, early-generation selection for quality characteristics appears to be effective.

Consumption of feedstuffs contaminated by Fusarium mycotoxins and the development of equine gastric ulcer syndrome (EGUS) affect the overall health of horses. A study was conducted to determine if feed-borne mycotoxins have an effect on EGUS, and the efficacy of a glucomannan mycotoxin adsorbent (GMA) was determined. Feed intake was decreased with the GMA diet compared to control horses. Body weight, ulcer score and gastrin concentration were unaffected by diet. Some significant changes in blood parameters potentially indicate liver damage and inhibition of protein synthesis. Histological evaluation showed an increase in mononuclear cells in the glandular region of the contaminated group likely indicating signs of gastritis. The incorporation of the GMA may reduce these negative effects on the horse based on our findings. It can be concluded that horses are susceptible to Fusarium mycotoxins with a possible effect on EGUS, as seen in the cells of the gastric glandular mucosa. / Alltech Inc., Nicholasville, Kentucky and OMAFRA

The agriculture industry experiences severe economic losses each year when wheat crops become infected with Fusarium and the mycotoxin Deoxynivalenol (DON). This research investigated the feasibility of using near infrared hyperspectral imaging to detect Fusarium damage and DON in Canadian Western Red Spring wheat. Four samples were selected from each grain grade resulting in 16 samples and 240 hyperspectral data cubes. The data cubes were calibrated to the system, the consistent spectra was found and then a 1- nearest neighbour classifier was generated. Grade percentages were computed and used to generate two 3- nearest neighbour classifiers, one for identifying Fusarium damage and the other for identifying DON content. The Fusarium damage classifier had an accuracy of 85% and the DON content classifier had an accuracy of 80%. While a single sample image classification will not replace manual testing, the use of multiple samples from one harvest could reduce manual inspections.

The principal objective of this investigation was to evaluate the effects of mycotoxin contaminated diets (deoxynivalenol (DON)), aflatoxin B1 (AFB1), and fumonisin (FUM)), with or without the use of a commercially available deactivating compound (DC), in young pullets and replacement laying hens on performance, reproductive, serological, and histopathological parameters. In trial 1, experimental treatments consisted of control, low toxin (1 µg DON/g + 1 µg AFB1/g), and high toxin (2 µg DON/g + 2 µg AFB1/g) diets. Pullets fed the high toxin diet had reduced (P<0.05) body weights compared to control and low toxin diets at d 14, 35, 49, 56, and 63. At d 21 and 28, there was a significant interaction observed between mycotoxin and DC inclusion in body weights. Following necropsies (d 35 and 65), relative liver weights and histopathological liver tissue damage were increased (P<0.05) in pullets fed high toxin diets when compared to control and low toxin diets. Relative kidney weights were increased (P<0.05) due to high toxin diet at d 65. Expected negative effects of toxin administration on titer development were not observed. The only interaction observed between mycotoxin administration and DC inclusion in trial 1 was on body weights. In trial 2, experimental treatments consisted of control, DON (9 µg/g) challenge, AFB1 (2 µg/g) + FUM (54 µg/g) challenge, and a mixed challenge (6 µg DON/g, 1 µg AFB1/g, and 27 µg FUM/g). All mycotoxin diets fed to hens negatively influenced (P<0.05) feed efficiency for the trial period spanning weeks 6 through 10 when compared to control diets. Egg production was not affected (P>0.05) by all mycotoxin diets weeks 6 through 10. Relative weights of the liver and kidney were increased (P<0.05) by AFB1+FUM challenge weeks 4 and 9 compared to control diet. The data reported in this study demonstrate that dietary DON and / or AFB1+FUM influence some performance, reproductive, histopathological, and egg quality traits, but by and large, replacement layer pullets seem to be relatively resistant to the mycotoxins evaluated in this trial at the described levels of administration.

This master thesis deals with monitoring of a content of deoxynivalenol, its metabolite deoxynivalenol-3-b-D-glucopyranoside and ochratoxin A in beer samples collected from retail market in the Czech Republic, Poland and Slovakia. The theoretical part describes general characteristics of mycotoxins, its transfer from field barely through malt to beer and its occurrence in beers. Malting process and brewing technology were also mentioned. Subsequently possibilities for a determination of the mycotoxins by the chromatografic and immunochemical method were presented. The experimental section describes analysis of 30 samples of beer. The analyses were conducted using ultra high-performance liquid chromatography with fluorimetric detection (UPLC/FLR) for ochratoxin A and high-performance liquid chromatography coupled with mass spectrometer (HPLC/MS) for deoxynivalenol and its metabolite. Ochratoxin A was detected in 25 of the 30 samples in concentration range of 0,6 - 82,5 ng·l-1. Deoxynivalenol was found in 24 of the 30 samples with concentration range of 2,29 - 12,57 ug·l-1 and deoxynivalenol-3-b-D-glucopyranoside was occure in 19 of the 30 samples in concentration range of 2,45 - 12,47 ug·l-1. It was also assessed the relationship between beer gushing and presence of mycotoxins in beer. No connection between the parameters has been found. Consequently it is not possible to predict beer gushing from the presence of mycotoxins.

No description available.

Mycotoxins are toxic secondary metabolites produced by fungi that are a threat to the health of humans and domestic animals. The most important mycotoxin in the U.S. is deoxynivalenol (DON), which causes symptoms such as vomiting, feed refusal, and weight loss in farm animals. The fungus Fusarium graminearum produces DON in staple crops such as wheat, barley, and corn. It is estimated that the economic losses associated with DON contamination alone exceed $650 million per year in the U.S. New strategies are needed to mitigate DON and improve food safety in the U.S. The overall goal of my research is to discover and employ microorganisms and enzymes to detoxify DON. The specific objectives are to: (1) discover and characterize microorganisms that detoxify DON, (2) use a cell free protein synthesis (CFPS) system to study enzymes that modify DON, (3) engineer yeast to detoxify DON with a metabolic engineering strategy, and (4) deliver a high school unit to teach high school students about mycotoxins in food. In Objective 1, two mixed cultures were identified from environmental samples that converted DON into the less toxic 3-keto-deoxynivalenol (3-keto-DON). In Objective 2, a CFPS system was used to express three known acetyltransferase genes to convert DON to 3-acetyl-DON (3-A-DON). In Objective 3, we identified a potential DON transporter from a library of randomly amplified fragments from the genomes of mixed cultures of microbes isolated from the environment. In Objective 4, we developed and delivered a unique high school unit to educate high school students about potential mycotoxins in food and feed products. The work presented here represents new and improved methods for mitigating mycotoxin contamination in the United States. / Ph. D.

Le Deoxynivalenol (DON) est une mycotoxine majeure retrouvée dans l’alimentation animale et celle-ci est connue pour réduire la fertilité des truies en inhibant la sécrétion de progestérone par les cellules de granulosa. Chez le bétail, DON est métabolisée en de-epoxy DON (DOM-1) dans le rumen, et DOM-1 peut atteindre des concentrations élevées dans le sang et les liquides folliculaires. Une des voies majeures de signalisation activée par DON est le ribotoxic stress response (RSR), lequel induit une auto-phosphorylation de la protéine kinase R (PKR) et réduit l’activation des MAP kinases incluant la MAPK3/1. Il n’a pas encore été démontré que ces mycotoxines affectent la reproduction chez les bovins. Les objectifs de cette thèse sont (1) de déterminer comment et à quelles doses DON affecte la fonction des cellules de granulosa et d’élucider les mécanismes d’action entrant en jeu; et (2) déterminer comment et à quelles doses la mycotoxine majeure DON et son métabolite DOM-1, affectent la fonction des cellules de la thèque chez le bétail. Les résultats sont présentés dans trois articles distincts. Dans le premier article, nous explorons les effets de DON sur les cellules de granulosa bovines; les traitements avec DON résultant en une inhibition significative de la sécrétion d’oestradiol et de progestérone (P4), et en une augmentation de la proportion de cellules apoptotiques après 4 jours de traitement. Les expériences de Western-Blot démontrent une stimulation significative de la phosphorylation de ERK1/2 et de MAPK14 entre 15 et 30 minutes après le début du traitement des cellules par DON. Par la suite, nous avons déterminé les effets de DON sur les gènes cibles de ERK1/2. En effet, les niveaux d’ARNm de EGR1 et FOS sont transitoirement augmentés avec des niveaux maximum à 1h de traitement par DON, tandis que les niveaux d’ARNm de iv COX2 et GADD45B sont augmentés mais plus de 24h après le début du traitement par DON. Dans le second article, les effets de DON et DOM-1 sur les cellules de thèque ont été étudiés. Le traitement des cellules par DOM-1 résulte en une inhibition dosedépendante de la sécrétion de P4 et de testostérone, et en une augmentation de la proportion de cellules apoptotiques, tandis que DON inhibe la sécrétion de P4 sans altérer celle de la testostérone ou bien le pourcentage de cellules mortes. Les deux mycotoxines sont effectives de manière maximale à des concentrations de 1 ng/ml (en revanche, DON affecte les cellules de granulosa à 100 ng/ml). Les résultats de Western-Blot démontrent la phosphorylation rapide de MAPK3/1, PKR et de JUN kinase après un traitement par DON ou DOM-1. En présence d’un inhibiteur spécifique de PKR, DON et DOM-1 sont incapables d’induire la phosphorylation de MAPK3/1, et l’effet inhibiteur de DON sur la phosphorylation de MAPK14 est en partie abrogé. Néanmoins, l’inhibiteur de PKR augmente davantage la phosphorylation de MAPK14 induite par DOM-1. Ensemble, ces résultats suggèrent que DON active le RSR dans les cellules de thèque et les cellules de granulosa bovines, et que les cellules de la thèque sont plus sensibles que les cellules de granulosa aux effets de DON. Ces données démontrent pour la première fois l’habilité de DOM-1 à affecter les fonctions et la survie cellulaires. / Deoxynivalenol (DON) is a major mycotoxin found in animal feed and is known to reduce fertility in pigs by inhibiting progesterone secretion from granulosa cells. In cattle, it is metabolized to de-epoxy DON (DOM-1) in the rumen, and DOM-1 can reach high concentrations in blood and follicular fluid. One of the major pathways activated by DON is the ribotoxic stress response (RSR), which involves autophosphorylation of protein kinase R (PKR) and downstream activation of MAP kinases including MAPK3/1. It is not known if these mycotoxins affect bovine reproduction. The objectives of present thesis were (1) to determine how and at what doses DON affects ovarian granulosa cell function and to elucidate its mechanism of action; and (2) to determine how and at what doses major mycotoxin DON and its metabolite DOM-1 affect theca cell function in cattle. The results are separated into three articles. In the first article the effects of DON on granulosa cells were explored; treatment with DON resulted in a significant inhibition of estradiol and progesterone (P4) secretion, and an increase in the proportion of apoptotic cells after 4 days of treatment. Western blot demonstrated significant upregulation of ERK1/2 and MAPK14 phosphorylation within 15-30 minutes of adding DON. We then determined the effect of DON on ERK1/2 target genes; EGR1 and FOS mRNA levels were transiently stimulated with maximum levels at 1 h of adding DON, whereas COX2 and GADD45B mRNA levels were upregulated but not until 24 h after DON treatment. In the second article, the effects of DON and DOM-1 on theca cells were assessed. Treatment with DOM-1 resulted in a dose-dependent inhibition of P4 and testosterone secretion, and an increase in the proportion of apoptotic cells, while DON inhibited P4 but did not alter testosterone secretion or the percentage of dead cells. Both ii DON and its metabolite were maximally effective at concentrations of 1 ng/ml (in contrast, the effects of DON on occur at 100ng/ml). Western blot demonstrated rapid phosphorylation of MAPK3/1, PKR and of JUN kinase after addition of DOM-1 or DON. Interestingly, phosphorylation of MAPK14 was significantly increased by DOM-1 but decreased by DON. The addition of a PKR inhibitor abrogated the ability of DON and DOM-1 to increase phosphorylation of MAPK3/1, and partly abrogated the inhibitory effect of DON on MAPK14 phosphorylation, however, the PKR inhibitor further increased the phosphorylation of MAPK14 caused by DOM-1. Together, these results suggest that DON activates the RSR in bovine granulosa and theca cells, and that theca cells are more sensitive than granulosa cells to the effects of DON. The data also demonstrate for the first time in any cell type the ability of DOM-1 to affect cell function and health.