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

Immunity Traits in Pigs: Substantial Genetic Variation and Limited Covariation

BACKGROUND: Increasing robustness via improvement of resistance to pathogens is a major selection objective in livestock breeding. As resistance traits are difficult or impossible to measure directly, potential indirect criteria are measures of immune traits (ITs). Our underlying hypothesis is that levels of ITs with no focus on specific pathogens define an individual's immunocompetence and thus predict response to pathogens in general. Since variation in ITs depends on genetic, environmental and probably epigenetic factors, our aim was to estimate the relative importance of genetics. In this report, we present a large genetic survey of innate and adaptive ITs in pig families bred in the same environment. METHODOLOGY/PRINCIPAL FINDINGS: Fifty four ITs were studied on 443 Large White pigs vaccinated against Mycoplasma hyopneumoniae and analyzed by combining a principal component analysis (PCA) and genetic parameter estimation. ITs include specific and non specific antibodies, seric inflammatory proteins, cell subsets by hemogram and flow cytometry, ex vivo production of cytokines (IFNα, TNFα, IL6, IL8, IL12, IFNγ, IL2, IL4, IL10), phagocytosis and lymphocyte proliferation. While six ITs had heritabilities that were weak or not significantly different from zero, 18 and 30 ITs had moderate (0.1<h2≤0.4) or high (h2>0.4) heritability values, respectively. Phenotypic and genetic correlations between ITs were weak except for a few traits that mostly include cell subsets. PCA revealed no cluster of innate or adaptive ITs. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that variation in many innate and adaptive ITs is genetically controlled in swine, as already reported for a smaller number of traits by other laboratories. A limited redundancy of the traits was also observed confirming the high degree of complementarity between innate and adaptive ITs. Our data provide a genetic framework for choosing ITs to be included as selection criteria in multitrait selection programmes that aim to improve both production and health traits

Acquisition de l'immunité passive chez des porcelets issus de truies exemptes d'organismes pathogènes spécifiques "EOPS"

National audienc

Biotransformation Approaches To Alleviate the Effects Induced byFusarium Mycotoxins in Swine

Mycotoxin mitigation is of major interest as ingestion of mycotoxins results in poor animal health, decreasedproductivity, as well as substantial economic losses. A feed additive (FA) consisting of a combination of bacteria (EubacteriumBBSH797) and enzyme (fumonisin esterase FumD) was tested in pigs for its ability to neutralize the effects of mono- and cocontaminateddiets with deoxynivalenol (DON) and fumonisins (FB) on hematology, biochemistry, tissue morphology, andimmune response. Forty-eight animals, allocated into eight groups, received one of eight diets for 35 days: a control diet, a dietcontaminated with either DON (3 mg/kg) or FB (6 mg/kg), or both toxins, and the same four diets with FA. Inclusion of FArestored the circulating number of neutrophils of piglets fed the FB and DON + FB diets. Similarly, FA counteracted the minorchanges observed on plasma concentrations of albumin and creatinine. In lung, the lesions induced by the ingestion of FB inmono- and co-contaminated diets were no longer observed after addition of FA in these diets. Lesions recorded in the liver ofpigs fed either of the contaminated diets with FA were partly reduced, and the increased hepatocyte proliferation was totallyneutralized when FA was present in the co-contaminated diet. After 35 days of exposure, the development of the vaccinalresponse was significantly improved in animals fed diets supplemented with FA, as shown by results of lymphocyte proliferation,cytokine expression in spleen, and the production of specific Ig. Similarly, in jejunum of animals fed diets with FA, occurrence oflesions and upregulation of pro-inflammatory cytokines were much less obvious. The ameliorative effects provided by FA suggestthat this approach would be suitable in the control of DON and FB that commonly co-occur in feed

Fumonisin-exposure impairs age-related ecological succession of bacterial species in weaned pig gut microbiota

Pigs are highly affected by dietary mycotoxin contamination and particularly by fumonisin. The effects of fumonisin on pig intestinal health are well documented, but little is known regarding its impact on gut microbiota. We investigate the effects of the fumonisin (FB1, 12 mg/kg feed) on the fecal microbiota of piglets (n = 6) after 0, 8, 15, 22, and 29 days of exposure. A control group of six piglets received a diet free of FB1. Bacterial community diversity, structure and taxonomic composition were carried out by V3⁻V4 16S rRNA gene sequencing. Exposure to FB1 decreases the diversity index, and shifts and constrains the structure and the composition of the bacterial community. This takes place as early as after 15 days of exposure and is at a maximum after 22 days of exposure. Compared to control, FB1 alters the ecological succession of fecal microbiota species toward higher levels of Lactobacillus and lower levels of the Lachnospiraceae and Veillonellaceae families, and particularly OTUs (Operational Taxonomic Units) of the genera Mitsuokella, Faecalibacterium and Roseburia. In conclusion, FB1 shifts and constrains age-related evolution of microbiota. The direct or indirect contribution of FB1 microbiota alteration in the global host response to FB1 toxicity remains to be investigated

The mycotoxins deoxynivalenol and nivalenol show in vivo synergism on jejunum enterocytes apoptosis

Remerciements : Plate-forme CIRE Chirurgie et Imagerie pour la Recherche et l’Enseignement, INRA, UMR PRC 37380 Nouzilly, Centre Val de LoireThe mycotoxins deoxynivalenol (DON) and nivalenol (NIV), worldwide cereal contaminants, raise concerns for human and animal gut health, following exposure through contaminated food and feed. The aim of this work was to analyze the effects of DON and NIV, alone or associated, on the intestinal pig mucosa. Jejunal loops were used for testing DON and NIV individually and in combination (1:1) after a single exposure, for 24 hours. For repeated exposure, piglets received a natural contaminated feed, with DON or with DON+NIV for 28 days. Histological investigations, proliferation and apoptosis assessments were conducted. Both experiments were concordant for the total-cell proliferation decreased at the villus tips after DON or DON+NIV at 10 μM acutely, or repeatedly, by 30-35% and 20-25%, respectively. In loops model, apoptotic enterocytes at villus tips increased dose-dependently after DON, NIV alone or DON+NIV in combination. The combination in loops at 10 μM showed higher effects on proliferation and apoptosis than DON alone, and synergism was shown for villus apoptotic enterocyte. These results are to be considered for NIV consumer risk assessment. Our results demonstrate the in vivo disruption of the intestinal balance proliferation/apoptosis explaining, at least partly, the disruption of intestinal barrier by these mycotoxins

Individual and combined effects of subclinical doses of deoxynivalenol and fumonisins in piglets

International audienceScope: Deoxynivalenol (DON) and fumonisins (FB) are the most frequently encounteredmycotoxins produced by Fusarium species and most commonly co-occur in animal diets.These mycotoxins were studied for their toxicity in piglets on several parameters includingplasma biochemistry, organ histopathology and immune response.Methods and results: Twenty-four 5-wk-old animals were randomly assigned to four differentgroups, receiving separate diets for 5 wk, a control diet, a diet contaminated with either DON(3 mg/kg) or FB (6 mg/kg) or both toxins. At days 4 and 16 of the trial, the animals weresubcutaneously immunized with ovalbumin to assess their specific immune response. Thedifferent diets did not affect animal performance and had minimal effect on hematologicaland biochemical blood parameters. By contrast, DON and FB induced histopathologicallesions in the liver, the lungs and the kidneys of exposed animals. The liver was significantlymore affected when the two mycotoxins were present simultaneously. The contaminateddiets also altered the specific immune response upon vaccination as measured by reducedanti-ovalbumin IgG level in the plasma and reduced lymphocyte proliferation upon antigenicstimulation. Because cytokines play a key role in immunity, the expression levels of IL-8, IL-1b, IL-6 and macrophage inflammatory protein-1b were measured by RT-PCR at the end ofthe experiment. The expression of these four cytokines was significantly decreased in thespleen of piglets exposed to multi-contaminated diet.Conclusion: Taken together, our data indicate that ingestion of multi-contaminated dietinduces greater histopathological lesions and higher immune suppression than ingestion ofmono-contaminated diets

Fumonisins at Doses below EU Regulatory Limits Induce Histological Alterations in Piglets

Fumonisins (FBs) are mycotoxins produced by Fusarium species that can contaminate human food and animal feed. Due to the harmful effects of FBs on animals, the European Union (EU) defined a recommendation of a maximum of 5 mg FBs (B1 + B2)/kg for complete feed for swine and 1 &micro;g FBs/kg body weight per day as the tolerable daily intake for humans. The aim of this study was to evaluate the toxicity of dietary exposure to low doses of FBs, including a dose below the EU regulatory limits. Four groups of 24 weaned castrated male piglets were exposed to feed containing 0, 3.7, 8.1, and 12.2 mg/kg of FBs for 28 days; the impact was measured by biochemical analysis and histopathological observations. Dietary exposure to FBs at a low dose (3.7 mg/kg of feed) significantly increased the plasma sphinganine-to-sphingosine ratio. FBs-contaminated diets led to histological modifications in the intestine, heart, lung, lymphoid organs, kidney, and liver. The histological alterations in the heart and the intestine appeared at the lowest dose of FBs-contaminated diet (3.7 mg/kg feed) and in the kidney at the intermediate dose (8.1 mg/kg feed). At the highest dose tested (12.2 mg/kg feed), all the organs displayed histological alterations. This dose also induced biochemical modifications indicative of kidney and liver alterations. In conclusion, our data indicate that FBs-contaminated diets at doses below the EU regulatory limit cause histological lesions in several organs. This study suggests that EU recommendations for the concentration of FBs in animal feed, especially for swine, are not sufficiently protective and that regulatory doses should be modified for better protection of animal health

1H-NMR metabolomics response to a realistic diet contamination with the mycotoxin deoxynivalenol: Effect of probiotics supplementation

International audienceLow-level contamination of food and feed by mycotoxin deoxynivalenol (DON) is unavoidable. We investigated the effects of subclinical challenge with DON, and dietary supplementation with probiotic yeast Saccharomyces cerevisiae boulardii I1079 as preventive strategy. Thirty-six piglets were randomly assigned to four different diets: control diet, diet contaminated with DON (3 mg/kg), diet supplemented with yeast (4x10 9 CFU/kg), or DON-contaminated diet supplemented with yeast, for four weeks. Plasma samples were collected for biochemistry, and tissue samples for histology. 1 H-NMR untargeted metabolomics of plasma and liver were also explored. DON induced no significant modification of biochemistry parameters. However, higher lesional scores were observed and metabolomics highlighted alteration of the metabolism of amino acids and 2-oxocarboxylic acids. Administration of yeast impacted aminoacyl-tRNA synthesis and metabolism of amino acids and glycerophospholipids. Yeast supplementation to DON-exposed piglets prevented histological alterations, while partial least square discriminant analysis underlined similarity of their plasma metabolic profile to control group. In contrast to plasma, the effect on liver metabolome remained marginal, indicating that the toxicity of the mycotoxin was not abolished. These data indicate that 1 H-NMR metabolomics profile is a good biomarker for subclinical exposure to DON, and supplementation with S. cerevisiae boulardii increases piglet resilience to this mycotoxin