In vivo contribution of deoxynivalenol-3-ß-D-glucoside to deoxynivalenol exposure in broiler chickens and pigs: oral bioavailability, hydrolysis and toxicokinetics.

Crossover animal trials were performed with intravenous and oral administration of deoxynivalenol-3-ß-D-glucoside (DON3G) and deoxynivalenol (DON) to broiler chickens and pigs. Systemic plasma concentrations of DON, DON3G and de-epoxy-DON were quantified using liquid chromatography-tandem mass spectrometry. Liquid chromatography coupled to high-resolution mass spectrometry was used to unravel phase II metabolism of DON. Additionally for pigs, portal plasma was analysed to study presystemic hydrolysis and metabolism. Data were processed via tailor-made compartmental toxicokinetic models. The results in broiler chickens indicate that DON3G is not hydrolysed to DON in vivo. Furthermore, the absolute oral bioavailability of DON3G in broiler chickens was low (3.79 ± 2.68 %) and comparable to that of DON (5.56 ± 2.05 %). After PO DON3G administration to pigs, only DON was detected in plasma, indicating a complete presystemic hydrolysis of the absorbed fraction of DON3G. However, the absorbed fraction of DON3G, recovered as DON, was approximately 5 times lower than after PO DON administration, 16.1 ± 5.4 compared with 81.3 ± 17.4 %. Analysis of phase II metabolites revealed that biotransformation of DON and DON3G in pigs mainly consists of glucuronidation, whereas in chickens predominantly conjugation with sulphate occurred. The extent of phase II metabolism is notably higher for chickens than for pigs, which might explain the differences in sensitivity of these species to DON. Although in vitro studies demonstrate a decreased toxicity of DON3G compared with DON, the species-dependent toxicokinetic data and in vivo hydrolysis to DON illustrate the toxicological relevance and consequently the need for further research to establish a tolerable daily intake.

Insights into In Vivo Absolute Oral Bioavailability, Biotransformation, and Toxicokinetics of Zearalenone, α-Zearalenol, ß-Zearalenol, Zearalenone-14-glucoside, and Zearalenone-14-sulfate in Pigs.

The aim of this study was to determine the toxicokinetic characteristics of ZEN and its modified forms, α-zearalenol (α-ZEL), ß-zearalenol (ß-ZEL), zearalenone-14-glucoside (ZEN14G), and zearalenone-14-sulfate (ZEN14S), including presystemic and systemic hydrolysis in pigs. Crossover pig trials were performed by means of intravenous and oral administration of ZEN and its modified forms. Systemic plasma concentrations of the administered toxins and their metabolites were quantified and further processed via tailor-made compartmental toxicokinetic models. Furthermore, portal plasma was analyzed to unravel the site of hydrolysis, and urine samples were analyzed to determine urinary excretion. Results demonstrate complete presystemic hydrolysis of ZEN14G and ZEN14S to ZEN and high oral bioavailability for all administered compounds, with further extensive first-pass glucuronidation. Conclusively, the modified-ZEN forms α-ZEL, ß-ZEL, ZEN14G, and ZEN14S contribute to overall ZEN systemic toxicity in pigs and should be taken into account for risk assessment.

T-2 Toxin-3α-glucoside in Broiler Chickens: Toxicokinetics, Absolute Oral Bioavailability, and in Vivo Hydrolysis.

Due to the lack of information on bioavailability and toxicity of modified mycotoxins, current risk assessment on these modified forms assumes an identical toxicity of the modified form to their respective unmodified counterparts. Crossover animal trials were performed with intravenous and oral administration of T-2 toxin (T-2) and T-2 toxin-3α-glucoside (T2-G) to broiler chickens. Plasma concentrations of T2-G, T-2, and main phase I metabolites were quantified using a validated liquid chromatography-tandem mass spectrometry method with a limit of quantitation for all compounds of 0.1 ng/mL. Resulting plasma concentration-time profiles were processed via two-compartmental toxicokinetic models. No T-2 triol and only traces of HT-2 were detected in the plasma samples after both intravenous and oral administration. The results indicate that T-2 has a low absolute oral bioavailability of 2.17 ± 1.80%. For T2-G, an absorbed fraction of the dose and absolute oral bioavailability of 10.4 ± 8.7% and 10.1 ± 8.5% were observed, respectively. This slight difference is caused by a minimal (and neglectable) presystemic hydrolysis of T2-G to T-2, that is, 3.49 ± 1.19%. Although low, the absorbed fraction of T2-G is 5 times higher than that of T-2. These differences in toxicokinetics parameters between T-2 and T2-G clearly indicate the flaw in assuming equal bioavailability and/or toxicity of modified and free mycotoxins in current risk assessments.

Role of mycotoxins in herds with and without problems with tail necrosis in neonatal pigs.

This study aimed to investigate a possible involvement of mycotoxins in neonatal tail necrosis in piglets. Ten affected and 10 non-affected farms were selected. Sow feed samples were analysed for the presence of 23 mycotoxins by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Blood plasma samples of sows and their piglets were analysed for the presence of deoxynivalenol (DON), de-epoxydeoxynivalenol, T-2 and HT-2 toxin, zearalenone, alfa-zearalenol, and beta-zearalenol, using LC-MS/MS. Additionally, high-resolution mass spectrometry (HRMS) was performed to detect DON-glucuronide (DON-Glca). There was a significant difference between case herds and control herds for mean DON concentrations in feed and sow plasma. For piglet samples, concentrations of DON were above the limit of quantification of 0.1 ng/ml in only 12 samples. Positive correlations were found between DON concentrations in sow feed and plasma of sows; DON concentration in sow feed and DON-Glca concentration in plasma of sows; and between DON and DON-Glca concentration in sow-plasma. In conclusion, high prevalence of DON in feed samples was found, with significantly higher concentrations in case herds, as well as the presence of DON and DON-Glca in sow plasma. Additional research is needed to identify risk factors, including within-herd factors, associated with neonatal tail necrosis in piglets.

The Impact of Deoxynivalenol on Pigeon Health: Occurrence in Feed, Toxicokinetics and Interaction with Salmonellosis.

Seed-based pigeon diets could be expected to result in exposure of pigeons to mycotoxins such as deoxynivalenol (DON). Ingestion of low to moderate contamination levels of DON may impair intestinal health, immune function and/or pathogen fitness, resulting in altered host-pathogen interactions and thus different outcome of infections. Here we demonstrate that DON was one of the most frequently detected mycotoxins in seed-based racing pigeons feed, contaminating 5 out of 10 samples (range 177-1,466 µg/kg). Subsequently, a toxicokinetic analysis revealed a low absolute oral bioavailability (F) of DON in pigeons (30.4%), which is comparable to other avian species. Furthermore, semi-quantitative analysis using high-resolution mass spectrometry revealed that DON-3α-sulphate is the major metabolite of DON in pigeons after intravenous as well as oral administration. Following ingestion of DON contaminated feed, the intestinal epithelial cells are exposed to significant DON concentrations which eventually may affect intestinal translocation and colonization of bacteria. Feeding pigeons a DON contaminated diet resulted in an increased percentage of pigeons shedding Salmonella compared to birds fed control diet, 87 ± 17% versus 74 ± 13%, respectively. However, no impact of DON was observed on the Salmonella induced disease signs, organ lesions, faecal and organ Salmonella counts. The presented risk assessment indicates that pigeons are frequently exposed to mycotoxins such as DON, which can affect the outcome of a Salmonella infection. The increasing number of pigeons shedding Salmonella suggests that DON can promote the spread of the bacterium within pigeon populations.

Comparative in vitro cytotoxicity of modified deoxynivalenol on porcine intestinal epithelial cells.

The gastrointestinal tract is the first target after ingestion of the mycotoxin deoxynivalenol (DON) via feed and food. Deoxynivalenol is known to affect the proliferation and viability of animal and human intestinal epithelial cells. In addition to DON, feed and food is often co-contaminated with modified forms of DON, such as 3-acetyldeoxynivalenol (3ADON), 15-acetyl-deoxynivalenol (15ADON) and deoxynivalenol-3-ß-D-glucoside (DON3G). The goal of this study was to determine the in vitro intrinsic cytotoxicity of these modified forms towards differentiated and proliferative porcine intestinal epithelial cells by means of flow cytometry. Cell death was assessed by dual staining with Annexin-V-fluorescein isothiocyanate (FITC) and propidium iodide (PI), which allows the discrimination of viable (FITC-/PI-), apoptotic (FITC+/PI-) and necrotic cells (FITC+/PI+). Based on the data from the presented pilot in vitro study, it is concluded that cytotoxicity for proliferative cells can be ranked as follows: DON3G â‰ª 3ADON < DON≈15ADON.

In Vitro Adsorption and in Vivo Pharmacokinetic Interaction between Doxycycline and Frequently Used Mycotoxin Binders in Broiler Chickens.

Mycotoxin binders are readily mixed in feeds to prevent uptake of mycotoxins by the animal. Concerns were raised for nonspecific binding with orally administered veterinary drugs by the European Food Safety Authority in 2010. This paper describes the screening for in vitro adsorption of doxycycline-a broad-spectrum tetracycline antibiotic-to six different binders that were able to bind >75% of the doxycycline. Next, an in vivo pharmacokinetic interaction study of doxycycline with two of the binders, which demonstrated significant in vitro binding, was performed in broiler chickens using an oral bolus model. It was shown that two montmorillonite-based binders were able to lower the area under the plasma concentration-time curve of doxycycline by >60% compared to the control group. These results may indicate a possible risk for reduced efficacy of doxycycline when used concomitantly with montmorillonite-based mycotoxin binders.

Comparative toxicokinetics, absolute oral bioavailability, and biotransformation of zearalenone in different poultry species.

After oral (PO) and intravenous (IV) administration of zearalenone (ZEN) to broiler chickens, laying hens, and turkey poults, the mycotoxin was rapidly absorbed (Tmax = 0.32-0.97 h) in all three species; however, the absolute oral bioavailability was low (F% = 6.87-10.28%). Next, also a rapid elimination of the mycotoxin in all poultry species was observed (T(1/2el) = 0.29-0.46 h). Both α- and ß-zearalenone (ZEL) were formed equally after IV administration in all species studied, whereas an increased biotransformation to ß-ZEL was demonstrated after PO administration, indicating presystemic biotransformation mainly in broiler chickens and laying hens. In comparison to the latter, turkey poults demonstrated a more extensive biotransformation of ZEN to α-ZEL after PO administration which could, in combination with the observed higher volume of distribution of ZEN, indicate a higher sensitivity of this species to the effects of ZEN in comparison to other poultry species.

Modified Fusarium mycotoxins unmasked: From occurrence in cereals to animal and human excretion.

Modified mycotoxins formed by plants, fungi and during some food processing steps may remain undetected by analytical methods, potentially causing underestimation of mycotoxin exposure and risk. Furthermore, due to altered physico-chemical characteristics of modified mycotoxins, these compounds might have different gastro-intestinal absorption compared to the unmodified forms, leading to altered modified mycotoxin plasma concentrations. Additionally, modified mycotoxins can be converted back into their corresponding unmodified forms by in vivo hydrolysis upon oral ingestion. This review aims to describe the current knowledge on the production, occurrence, toxicity and toxicokinetic properties of the modified Fusarium mycotoxins. The need for more occurrence data to correctly assess the risks associated with these modified mycotoxins is clearly indicated, including differences between commodities as well as geographical and climatological influences. Research on toxicity of these modified forms demonstrates the possibility of significant decreases as well as increases in the toxic effects of these compounds compared with those of the unmodified forms. Their toxicokinetics demonstrates that a decreased (increased) polarity of modified mycotoxins might cause enhanced (decreased) oral absorption. The possibility of in vivo hydrolysis, altered toxicity and their wide-spread occurrence makes modified mycotoxins a complex threat for which a risk assessment will require prospective multi-disciplinary efforts.

Quantitative Determination of Tenuazonic Acid in Pig and Broiler Chicken Plasma by LC-MS/MS and Its Comparative Toxicokinetics.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantitate tenuazonic acid (TeA) in pig and broiler chicken plasma was successfully developed and validated. Linear matrix-matched calibration curves ranged between 5 and 200 ng/mL. Correlation coefficients, goodness-of-fit coefficients, and within-day and between-day precision and accuracy fell well within the acceptance criteria. The limit of quantitation was 5.0 ng/mL in both pig and broiler chicken plasma. The LC-MS/MS method was applied in a comparative toxicokinetic study in both pigs and broiler chickens. TeA was completely bioavailable after oral administration in both animal species. However, absorption was deemed to be slower in broiler chickens (mean tmax 0.32 h in pigs vs 2.60 h in chickens). TeA was more slowly eliminated in broiler chickens (mean t1/2el 0.55 h in pigs vs 2.45 h in chickens after oral administration), mainly due to the significantly lower total body clearance (mean Cl 446.1 mL/h/kg in pigs vs 59.2 mL/h/kg in chickens after oral administration). Tissue residue studies and further research to elucidate the biotransformation and excretion processes of TeA in pigs, broiler chickens, and other animal species are imperative.

Oral Bioavailability, Hydrolysis, and Comparative Toxicokinetics of 3-Acetyldeoxynivalenol and 15-Acetyldeoxynivalenol in Broiler Chickens and Pigs.

The goal of this study was to determine the absolute oral bioavailability, (presystemic) hydrolysis and toxicokinetic characteristics of deoxynivalenol, 3-acetyldeoxynivalenol, and 15-acetyldeoxynivalenol in broiler chickens and pigs. Crossover animal trials were performed with intravenous and oral administration of deoxynivalenol, 3-acetyldeoxynivalenol, and 15-acetyldeoxynivalenol to broilers and pigs. Plasma concentrations were analyzed by using liquid chromatography-tandem mass spectrometry, and data were processed via a tailor-made compartmental toxicokinetic analysis. The results in broiler chickens showed that the absorbed fraction after oral deoxynivalenol, 3-acetyldeoxynivalenol, and 15-acetyldeoxynivalenol administration was 10.6, 18.2, and 42.2%, respectively. This fraction was completely hydrolyzed presystemically for 3-acetyldeoxynivalenol to deoxynivalenol and to a lesser extent (75.4%) for 15-acetyldeoxynivalenol. In pigs, the absorbed fractions were 100% for deoxynivalenol, 3-acetyldeoxynivalenol, and 15-acetyldeoxynivalenol, and both 3-acetyldeoxynivalenol and 15-acetyldeoxynivalenol were completely hydrolyzed presystemically. The disposition properties of 3-acetyldeoxynivalenol and 15-acetyldeoxynivalenol demonstrate their toxicological relevance and consequently the possible need to establish a tolerable daily intake.

Pilot toxicokinetic study and absolute oral bioavailability of the Fusarium mycotoxin enniatin B1 in pigs.

The aim of present study was to reveal the toxicokinetic properties and absolute oral bioavailability of enniatin B1 in pigs. Five pigs were administered this Fusarium mycotoxin per os and intravenously in a two-way cross-over design. The toxicokinetic profile fitted a two-compartmental model. Enniatin B1 is rapidly absorbed after oral administration (T(1/2a)=0.15 h, Tmax=0.24h) and rapidly distributed and eliminated as well (T(1/2elα)=0.15 h; T(1/2elß)=1.57 h). The absolute oral bioavailability is high (90.9%), indicating a clear systemic exposure. After intravenous administration, the mycotoxin is distributed and eliminated rapidly (T(1/2elα)=0.15 h; T(1/2elß)=1.13 h), in accordance with oral administration.