Subchronic dietary exposure of rats to cadmium alters the metabolism of metals essential to bone health

Cadmium (Cd) was recently identified as a risk factor for osteoporosis. Skeletal damage may be the critical effect of low-level long-term exposure to Cd in the general population exposed via food, but the mechanisms behind this are not clearly understood.We investigated the effects of dietary Cd exposure on metals involved in bone turnover. Female rats received a Cd-supplemented diet (0, 10, 50, or 200 CdCl2 mg/kg diet) for 13 weeks. Cd and essential metals stored in the liver were measured by ICP-MS multianalysis. Mineral content of the livers was modified according to Cd level : iron, magnesium and selenium decreased while copper, zinc and manganese increased with increasing Cd levels. Iron was the most strikingly affected metal, falling to one-fifth of control values at high dietary Cd exposure. In this dosage group, selenium decreased to 36% of mean control concentrations while zinc increased to 168%. This mineral imbalance, especially depleted iron stores, can contribute, at least in part, to the Cd-associated risk of osteoporosis. The association between iron metabolism and Cd exposure should be investigated in humans, as Cd and low iron stores could act synergistically as risk factors for osteoporosis

HPLC assay of zearalenone and reduced metabolites in S9 fractions of duck liver

HPLC analysis of zearalenone (ZEA), zearalenols (-ZOL and ß-ZOL) and zearalanols (-ZAL and ß-ZAL) was developed, in order to obtain a sensitive and reproducible method to quantify ZEA and its reduced metabolites in subcellular fractions of animal livers (S9 samples). Optimal in vitro metabolism was observed by incubating 5 mg S9 proteins with 0.016 μmol. ZEA. Acetonitrile and diethylether/chloroform mixture were compared for extraction, as well as different mobile phases and two detection modes in HPLC analysis. Extracted samples were eluted with water/acetonitrile (55:45, v/v) at a flow-rate of 1.0 ml/min-1, resulting in well separated peaks between ZEA and the metabolites. The limits of detection ranged from 0.5 to 2 ng/mg S9 proteins using UV, and from 0.04 to 4 ng/mg S9 proteins, using fluorescence detection. Fluorescence showed a ten-fold higher sensitivity than UV detection for ZEA and -ZOL. Repeatability (10 assays) was 2.7% to 6.99% for zearalenols. Day-by-day coefficients of variation for zearalenone and zeranols with UV detection were 3.3 to 8.5 %, and 2.5 to 4.3 %, respectively. This analysis applied to S9 samples from ducks after 30 min of ZEA incubation allowed to demonstrate that -ZOL is the main reduced metabolite in the duck. The present method is particularly adapted for studying in vitro metabolism of ZEA and inter-species variations

Variations in zearalenone activation in avian food species

Zearalenone (ZEA), a widely distributed oestrogenic fusariotoxin, constitutes a potential risk for human and animal health. ZEA is metabolised to the main metabolites identified in vitro and in vivo: alpha-zearalenol (α-ZOL) and beta-zearalenol (β-ZOL). The efficiency to produce alpha-reduced metabolites appears of particular interest in risk assessment as alpha-reduced metabolites constitute activated forms whereas beta-reduced metabolites are less oestrogenic than ZEA. In this study ZEA activation was compared in avian food species. ZEA and its reduced metabolites were quantified in subcellular fractions of six avian species and rat livers. The α-ZOL/β-ZOL ratio in rats was 19. The various avian food species cannot be considered to be equivalent in terms of ZEA reduction (P<0.001). Quails represented high “beta reducers”, with α-ZOL/β-ZOL ratio less than two. Weak “beta reducers” included on one part ducks and chickens showing α-ZOL/β-ZOL ratio greater than 3 and up to 5.6 and on a second part geese, showing a lower production of α-ZOL than other poultry. Comparisons of enzyme kinetics in ducks and in quails show that these variations can be explained by the action of various isoforms of dehydrogenases. These results are relevant to food safety, in the context of frequently inevitable contamination of animal feed

Development of a pig jejunal explant culture for studying the gastrointestinal toxicity of the mycotoxin deoxynivalenol: histopathological analysis

The digestive tract is a target for the mycotoxin deoxynivalenol (DON), a major cereals grain contaminant of public health concern in Europe and North America. Pig, the most sensitive species to DON toxicity, can be regarded as the most relevant animal model for studying the intestinal effects of DON. A pig jejunal explants culture was developed to assess short-term effects of DON. In a first step, jejunal explants from 9-13 week-old and from 4-5 week-old pigs were cultured in vitro for up to 8 hours. Explants from younger animals were better preserved after 8 hours, as assessed by morphological scores and by villi lengths. In a second step, dose-related alterations of the jejunal tissue were observed, including shortened and coalescent villi, lysis of enterocytes, oedema. After 4h of DON exposure of explants from 4-5 week-old pigs, a no-effect concentration level of 1 µM was estimated (corresponding to diet contaminated with 0.3 mg DON/kg) based on morphological scores, and of 0.2 µM based on villi lengths. In conclusion, our data indicate that pig intestinal explants represent a relevant and sensitive model to investigate the effects of food contaminants

The low intestinal and hepatic toxicity of hydrolyzed fumonisin B1 correlates with its inability to alter the metabolism of sphingolipids

Fumonisins are mycotoxins frequently found as natural contaminants in maize, where they are produced by the plant pathogen Fusarium verticillioides. They are toxic to animals and exert their effects through mechanisms involving disruption of sphingolipid metabolism.Fumonisin B1 (FB1) is the predominant fumonisins in this family. FB1 is converted to its hydrolyzed analogs HFB1, by alkaline cooking (nixtamalization) or through enzymatic degradation. The toxicity of HFB1 is poorly documented especially at the intestinal level. The objectives of this study were to compare the toxicity of HFB1 and FB1 and to assess the ability of these toxins to disrupt sphingolipids biosynthesis. HFB1 was obtained by a deesterification of FB1, with a carboxylesterase. Piglets, animals highly sensitive to FB1, were exposed by gavage for 2 weeks to 2.8 µmol FB1 or HFB1/kg body weight/day. FB1 induced hepatotoxicity as indicated by the lesion score, the level of several biochemical analytes and the expression of inflammatory cytokines. Similarly, FB1 impaired the morphology of the different section of the small intestine, reduced villi height and modified intestinal cytokine expression. By contrast, HFB1 did not trigger hepatotoxicity, did not impair intestinal morphology and slightly modified the intestinal immune response. This low toxicity of HFB1 correlates with a weak alteration of the sphinganine/sphingosine ratio in the liver and in the plasma. Taken together, these data demonstrate that HFB1 does not cause intestinal or hepatic toxicity in the sensitive pig model, and slightly disrupts sphingolipids metabolism. This finding suggests that conversion to HFB1 could be a good strategy to reduce FB1 exposure

The food contaminant deoxynivalenol, decreases intestinal barrier permeability and reduces claudin expression

The gastrointestinal tract represents the first barrier against food contaminants as well as the first target for these toxicants. Deoxynivalenol (DON) is a mycotoxin that commonly contaminates cereals and causes various toxicological effects. Through consumption of contaminated cereals and cereal products, human and pigs are exposed to this mycotoxin. Using in vitro, ex vivo, and in vivo approaches, we investigated the effects of DON on the intestinal epithelium. We demonstrated that, in intestinal epithelial cell lines from porcine (IPEC-1) or human (Caco-2) origin, DON decreases trans-epithelial electric resistance (TEER) and increases in a time and dose-dependent manner the paracellular permeability to 4 kDa dextran and to pathogenic Escherichia Coli across intestinal cell monolayers. In pig explants treated with DON, we also observed an increased permeability of intestinal tissue. These alterations of barrier function were associated with a specific reduction in the expression of claudins, which was also seen in vivo in the jejunum of piglets exposed to DON-contaminated feed. In conclusion, DON alters claudin expression and decreases the barrier function of the intestinal epithelium. Considering that high levels of DON may be present in food or feed, consumption of DON-contaminated food/feed may induce intestinal damage and has consequences for human and animal health

FELASA accreditation of education and training courses in laboratory animal science according to the Directive 2010/63/EU

This document describes how the Federation of European Laboratory Animal Science Associations (FELASA) accreditation addresses both the Directive 2010/63/EU and the related European Commission guidance document. The four EU Functions and beyond: FELASA accredits courses that fulfil the requirements of Functions A, B, C and D as defined by EU Directive, Article 23, as well as for designated veterinarians and specialists in laboratory animal science. Modularity and mobility: Cohesive courses for Functions and for very specific topics are accredited, but flexibility and mobility are possible: a researcher can start his/her training with one FELASA accredited course and complete other modules with another. A course organizer will deliver a FELASA certificate relating to the successfully completed modules. Accreditation process: The process consists of two major steps: (1) a review of full course documentation provided by the applicant will lead, if successful, to FELASA accreditation. The course is posted on the FELASA website as 'FELASA accredited' and the course provider can deliver FELASA certificates upon successful completion of the course; (2) successful accreditation is followed by an on-site course audit. In the case of a negative outcome of the audit, FELASA accreditation is withdrawn, the course is deleted from the list of FELASA accredited courses and FELASA certificates cannot be issued. To ensure that quality is maintained, continuation of accreditation requires regular revalidation

Conclusions of the French Food Safety Agency on the toxicity of bisphenol A

Since more than 10 years, risk assessment of bisphenol A (BPA) is debated at the international level. In 2008, the U.S. National Toxicology Program (NTP) expressed some concern for adverse effects, at current level of exposure to BPA, on developmental toxicity. In this context, the French Food Safety Agency (AFSSA) decided to review the toxicity data on BPA with a special focus on this endpoint at doses below 5mg/kg bw/day (the no observed adverse effect level set by different regulatory bodies). This paper summarizes the conclusions of a collective assessment conducted by an expert Working Group from AFSSA. Studies were classified into 3 groups: (i) finding no toxicity, (ii) reporting results not considered to be of concern and (iii) indicating warning signals. The term "warning signal" means that no formal conclusion can be drawn regarding the establishment of a health based guidance value but the study raises some questions about the toxicity of BPA at low doses. It was concluded that studies are needed to ascertain the significance for human health of these warning signals and to be able to propose new methodologies for assessing the risks associated with low doses of BPA and more generally of endocrine disruptors

Development of a pig jejunal explant culture for studying the gastrointestinal toxicity of the mycotoxin deoxynivalenol: Histopathological analysis. Toxicol

Abstract The digestive tract is a target for the mycotoxin deoxynivalenol (DON), a major cereals grain contaminant of public health concern in Europe and North America. Pig, the most sensitive species to DON toxicity, can be regarded as the most relevant animal model for studying the intestinal effects of DON. A pig jejunal explants culture was developed to assess short-term effects of DON. In a first step, jejunal explants from 9-13 week-old and from 4-5 week-old pigs were cultured in vitro for up to 8 hours. Explants from younger animals were better preserved after 8 hours, as assessed by morphological scores and by villi lengths. Dose-related alteration of the jejunal tissue were observed, including shortened and coalescent villi, lysis of enterocytes, oedema. A no-effect concentration level of 1 μM was estimated (corresponding to diet contaminated with 0.3 mg DON/kg) based on morphological scores, and of 0.2 μM based on villi lengths. In conclusion, our data indicate that pig intestinal explants represent a relevant and sensitive model to investigate the effects of food contaminants

Safety assessment of the substance (butadiene, styrene, methyl methacrylate, butyl acrylate) copolymer cross-linked with divinylbenzene or 1,3-butanediol dimethacrylate for use in food contact materials

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