Effect of low dose of fumonisins on pig health: immune status, intestinal microbiota and sensitivity to Salmonella

Agaro-oligosaccharides mitigate deoxynivalenol-induced intestinal inflammation by regulating gut microbiota and enhancing intestinal barrier function in mice

Agarose-derived agaro-oligosaccharides (AgaroS) have been extensively studied in terms of structures and bioactivities; they reportedly possess antioxidant and anti-inflammatory activities that maintain intestinal homeostasis and host health. However, the protective effects of AgaroS on deoxynivalenol (DON)-induced intestinal dysfunction remain unclear. We investigated the effects of AgaroS on DON-induced intestinal dysfunction in mice and explored the underlying protective mechanisms. In total, 32 mice were randomly allocated to four treatments (n = 8 each) for 28 days. From day 1 to day 21, the control (CON) and DON groups received oral phosphate-buffered saline (200 μL per day); the AgaroS and AgaroS + DON groups received 200 mg AgaroS per kg body weight once daily by orogastric gavage. Experimental intestinal injury was induced by adding DON (4.8 mg per kg body weight) via gavage from day 21 to day 28. Phosphate-buffered saline was administered once daily by gavage in the CON and AgaroS groups. Herein, AgaroS supplementation led to a higher final body weight and smaller body weight loss and a lower concentration of plasma inflammatory cytokines, compared with the DON group. The DON group showed a significantly reduced ileal villus height and villus height/crypt depth, compared with the CON and AgaroS + DON groups. However, AgaroS supplementation improved DON-induced intestinal injury in mice. Compared with the DON group, ileal and colonic protein expression levels of claudin, occludin, Ki67, and mucin2 were significantly higher in the AgaroS supplementation group. Colonic levels of the anti-inflammatory cytokine IL-1β tended to be higher in the DON group than in the AgaroS + DON group. AgaroS altered the gut microbiota composition, accompanied by increased production of short-chain fatty acids in mice. In conclusion, our findings highlight a promising anti-mycotoxin approach whereby AgaroS alleviate DON-induced intestinal inflammation by modulating intestinal barrier functional integrity and gut microbiota in mice.

Integrating network pharmacology and experimental validation to explore the mechanisms of luteolin in alleviating fumonisin B1-induced intestinal inflammatory injury

Contamination with fumonisin B1 (FB1) represents a global health problem. FB1 exposure may also trigger intestinal injury by activating inflammatory responses, leading to a reduction in production performance and economic benefits. However, the mechanism of FB1-induced intestinal inflammatory injury is still unclear. At the same time, it is urgent to develop antibiotic alternatives and therapeutic targets to alleviate antibiotic resistance and to ensure effective treatment of intestinal inflammatory injury. We combined network pharmacology and in vitro experiments to explore the core therapeutic targets and potential mechanism of luteolin in FB1-induced intestinal inflammatory injury. Network pharmacology and molecular docking revealed that nuclear factor kappa B (NF-κB) p65, extracellular signal-regulated kinase (ERK), interleukin 6 (IL-6) and IL-1β are the important targets, and the NF-κB and ERK signalling pathways are critical in FB1-induced intestinal inflammatory injury. Besides, in vitro experiments further demonstrated that luteolin can inhibit FB1-induced intestinal inflammatory injury by inhibiting activation of the NF-κB and ERK signalling pathways and reducing the expression of IL-6 and IL-1β in IPEC-J2 cells. We have comprehensively illustrated the potential targets and molecular mechanism by which luteolin can alleviate FB1-induced intestinal inflammatory injury. Luteolin may be an effective antibiotic alternative to prevent intestinal inflammatory injury.

Mycotoxins in Cereal-Based Products and Their Impacts on the Health of Humans, Livestock Animals and Pets

Cereal grains are the most important food staples for human beings and livestock animals. They can be processed into various types of food and feed products such as bread, pasta, breakfast cereals, cake, snacks, beer, complete feed, and pet foods. However, cereal grains are vulnerable to the contamination of soil microorganisms, particularly molds. The toxigenic fungi/molds not only cause quality deterioration and grain loss, but also produce toxic secondary metabolites, mycotoxins, which can cause acute toxicity, death, and chronic diseases such as cancer, immunity suppression, growth impairment, and neural tube defects in humans, livestock animals and pets. To protect human beings and animals from these health risks, many countries have established/adopted regulations to limit exposure to mycotoxins. The purpose of this review is to update the evidence regarding the occurrence and co-occurrence of mycotoxins in cereal grains and cereal-derived food and feed products and their health impacts on human beings, livestock animals and pets. The effort for safe food and feed supplies including prevention technologies, detoxification technologies/methods and up-to-date regulation limits of frequently detected mycotoxins in cereal grains for food and feed in major cereal-producing countries are also provided. Some important areas worthy of further investigation are proposed.

Gut-Faecal Microbial and Health-Marker Response to Dietary Fumonisins in Weaned Pigs

This study investigated effects of dietary fumonisins (FBs) on gut and faecal microbiota of weaned pigs. In total, 18 7-week-old male pigs were fed either 0, 15 or 30 mg FBs (FB₁ + FB₂ + FB₃)/kg diet for 21 days. The microbiota was analysed with amplicon sequencing of the 16S rRNA gene V3-V4 regions (Illumina MiSeq). Results showed no treatment effect (p > 0.05) on growth performance, serum reduced glutathione, glutathione peroxidase and malondialdehyde. FBs increased serum aspartate transaminase, gamma glutamyl-transferase and alkaline phosphatase activities. A 30 mg/kg FBs treatment shifted microbial population in the duodenum and ileum to lower levels (compared to control (p < 0.05)) of the families Campylobacteraceae and Clostridiaceae, respectively, as well as the genera Alloprevotella, Campylobacter and Lachnospiraceae Incertae Sedis (duodenum), Turicibacter (jejunum), and Clostridium sensu stricto 1 (ileum). Faecal microbiota had higher levels of the Erysipelotrichaceae and Ruminococcaceae families and Solobacterium, Faecalibacterium, Anaerofilum, Ruminococcus, Subdoligranulum, Pseudobutyrivibrio, Coprococcus and Roseburia genera in the 30 mg/kg FBs compared to control and/or to the 15 mg/kg FBs diets. Lactobacillus was more abundant in the duodenum compared to faeces in all treatment groups (p < 0.01). Overall, the 30 mg/kg FBs diet altered the pig gut microbiota without suppressing animal growth performance.

Subclinical doses of dietary fumonisins and deoxynivalenol cause cecal microbiota dysbiosis in broiler chickens challenged with Clostridium perfringens

Fusarium toxins are one of the most common contaminants in poultry diets. The co-occurrence of fumonisins (FUM) and deoxynivalenol (DON), even at a subclinical dose, negatively affects the growth performance, intestinal integrity and induce subclinical necrotic enteritis in broiler chickens. Loss of gut integrity can be expected to alter the intestinal microbiota’s composition. The objective of this study was to identify the effects of combined FUM and DON on the cecal microbiome profile and predicted metabolic functions and a short chain fatty acid profile in broilers challenged with Clostridium perfringens. A total of 240 1 day-old chicks were randomly assigned to two treatments: a control diet and the control diet with 3 mg/kg FUM + 4 mg/kg DON each with eight replications. All the birds were received cocci vaccine at d0. All birds in both treatment groups were challenged with C. perfringens 1 × 108 CFU via feed on d 19 and 20 to achieve 5% mortality. On d 35, the FUM and DON contaminated diet numerically (P = 0.06) decreased the body weight gain (BWG) by 84 g compared to the control group. The bacterial compositions of the cecal contents were analyzed by sequencing the V3–V4 region of the 16S rRNA gene. Overall, microbial richness and diversity increased (P &lt; 0.02) during the studied period (d 21–35). Cecal contents of birds in the FUM + DON group had greater (P &lt; 0.05) microbial evenness and diversity (Shannon index) compared to the control group. FUM + DON exposure decreased (P = 0.001) the relative abundance of Proteobacteria in the cecal content, compared to the control group. The combined FUM + DON significantly increased the relative abundance of the Defluviitaleaceae and Lachnospiraceae families (P &lt; 0.05) but decreased the abundances of the Moraxellaceae and Streptococcaceae (P &lt; 0.05) compared to the control group birds. At the genus level, FUM + DON exposure decreased (P &lt; 0.05) Acinetobacter and Pseudomonas abundance and had a tendency (P = 0.08) to decrease Thermincola abundance compared to the control group. In the ileum, no NE-specific microscopic abnormalities were found; however, the tip of the ileal villi were compromised. The present findings showed that dietary FUM and DON contamination, even at subclinical levels, altered cecal microbial composition, dysregulated intestinal functions, and impaired the gut immune response, potentially predisposing the birds to necrotic enteritis.

New perspectives in application of kidney biomarkers in mycotoxin induced nephrotoxicity, with a particular focus on domestic pigs

The gradual spread of Aspergilli worldwide is adding to the global shortage of food and is affecting its safe consumption. Aspergillus-derived mycotoxins, including aflatoxins and ochratoxin A, and fumonisins (members of the fusariotoxin group) can cause pathological damage to vital organs, including the kidney or liver. Although the kidney functions as the major excretory system in mammals, monitoring and screening for mycotoxin induced nephrotoxicity is only now a developmental area in the field of livestock feed toxicology. Currently the assessment of individual exposure to mycotoxins in man and animals is usually based on the analysis of toxin and/or metabolite contamination in the blood or urine. However, this requires selective and sensitive analytical methods (e.g., HPLC-MS/MS), which are time consuming and expensive. The toxicokinetic of mycotoxin metabolites is becoming better understood. Several kidney biomarkers are used successfully in drug development, however cost-efficient, and reliable kidney biomarkers are urgently needed for monitoring farm animals for early signs of kidney disease. β₂-microglobulin (β₂-MG) and N-acetyl-β-D-glucosaminidase (NAG) are the dominant biomarkers employed routinely in environmental toxicology research, while kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) are also emerging as effective markers to identify mycotoxin induced nephropathy. Pigs are exposed to mycotoxins due to their cereal-based diet and are particularly susceptible to Aspergillus mycotoxins. In addition to commonly used diagnostic markers for nephrotoxicity including plasma creatinine, NAG, KIM-1 and NGAL can be used in pigs. In this review, the currently available techniques are summarized, which are used for screening mycotoxin induced nephrotoxicity in farm animals. Possible approaches are considered, which could be used to detect mycotoxin induced nephropathy.

An update on T2-toxins: metabolism, immunotoxicity mechanism and human assessment exposure of intestinal microbiota

Mycotoxins are naturally produced secondary metabolites or low molecular organic compounds produced by fungus with high diversification, which cause mycotoxicosis (food contamination) in humans and animals. T-2 toxin is simply one of the metabolites belonging to fungi trichothecene mycotoxin. Specifically, Trichothecenes-2 (T-2) mycotoxin of genus fusarium is considered one of the most hotspot agricultural commodities and carcinogenic compounds worldwide. There are well-known examples of salmonellosis in mice and pigs, necrotic enteritis in chickens, catfish enteric septicemia and colibacillosis in pigs as T-2 toxic agent. On the other hand, it has shown a significant reduction in the Salmonella population's aptitude in the pig intestinal tract. Although the impact of the excess Fusarium contaminants on humans in creating infectious illness is less well-known, some toxins are harmful; for example, salmonellosis and colibacillosis have been frequently observed in humans. More than 20 different metabolites are synthesized and excreted after ingestion, but the T-2 toxin is one of the most protuberant metabolites. Less absorption of mycotoxins in intestinal tract results in biotransformation of toxic metabolites into less toxic variants. In addition to these, effects of microbiota on harmful mycotoxins are not limited to intestinal tract, it may harm the other human vital organs. However, detoxification of microbiota is considered as an alternative way to decontaminate the feed for both animals and humans. These transformations of toxic metabolites depend upon the formation of metabolites. This study is complete in all perspectives regarding interactions between microbiota and mycotoxins, their mechanism and practical applications based on experimental studies.

FumDSB can alleviate the inflammatory response induced by fumonisin B1 in growing pigs

Fumonisin B₁ (FB₁) has the highest natural contamination rate among all fumonisin analogs and can inhibit food intake and weight gain of pigs. Under laboratory conditions, carboxylesterase FumDSB has a high FB₁ degradation rate and excellent pH and thermal stability. The present study sought to estimate the effects of FumDSB on growing pigs from the perspective of a brain-intestinal axis. Twenty-four growing pigs of similar weight were divided into Control, FB₁ (5 mg FB₁/kg feed), and FumDSB (5 mg FB₁/kg and 0.1% FumDSB in the feed) groups. After 42 days of feeding, hypothalamus and jejunum samples were collected for quantitative real-time fluorescence, western blotting, and immunohistochemistry. The results showed that FB₁ consumption can destruct the tissue structure of hypothalamus and jejunum, affect the expression and distribution of several appetite-related neuropeptides and inflammatory cytokines, thereby inducing neuroinflammatory responses and affecting food intake and weight gain. However, these anorexia effects and inflammatory responses are alleviated when FumDSB is added to the feed. In short, FumDSB can alleviate the inflammatory response induced by FB₁ in growing pigs.

Short-term exposure to the mycotoxins zearalenone or fumonisins affects rumen fermentation and microbiota, and health variables in cattle

Zearalenone (ZEN) and fumonisins (FUM) jeopardize fertility and health in cattle; yet, their toxigenic effects on rumen health and microbiota, both being crucial for animal health, are not clarified. This study determined the effects of a short-term exposure to ZEN or FUM on the rumen ecosystem, and further evaluated acute implications on health parameters. Six cows were fed a basal diet with 40% grain (dry matter basis) and exposed to either 5 mg of ZEN or 20 mg of FUM daily for two consecutive days each, separated by a 7-days washout period. The exposure to ZEN or FUM led to a reduction of Lachnospiraceae and Prevotellaceae in the rumen. Similarly, ZEN lowered the ruminal pH and total short-chain fatty acid concentration, despite increased rumination activity of the cows. Fumonisins increased the number of observed features and significantly impacted β-diversity structure and metagenome predicted function. At the systemic level, FUM exposure suggested an immediate hepatotoxic effect, as evidenced by increased liver enzyme concentrations, which were accompanied by altered heart and respiratory rates. Similarly, ZEN increased the body temperature up to a mild fever. Concluding, short-term exposure to ZEN and FUM can harm the rumen ecosystem and acutely impair systemic health.

Tissular Genomic Responses to Oral FB1 Exposure in Pigs

Fumonisin B1 (FB1) is a widespread mycotoxin produced by fungal Fusarium species—mainly in maize, one of the plants most commonly used for food and feed. Pigs and horses are the animal species most susceptible to this mycotoxin. FB1 exposure can cause highly diverse clinical symptoms, including hepatotoxicity, immunotoxicity, and intestinal barrier function disturbance. Inhibition of ceramide synthetase is a well-understood ubiquitous molecular mechanism of FB1 toxicity, but other more tissue-specific effects remain to be elucidated. To investigate the effects of FB1 in different exposed tissues, we cross-analyzed the transcriptomes of fours organs: liver, jejunum, jejunal Peyer’s patches, and spleen. During a four-week study period, pigs were fed a control diet or a FB1-contaminated diet (10 mg/kg feed). In response to oral FB1 exposure, we observed common biological processes in the four organs, including predominant and recurrent processes (extracellular matrix organization, integrin activation, granulocyte chemotaxis, neutrophil migration, and lipid and sterol homeostasis), as well as more tissue-specific processes that appeared to be related to lipid outcomes (cell cycle regulation in jejunum, and gluconeogenesis in liver).

FumDSB Can Reduce the Toxic Effects of Fumonisin B1 by Regulating Several Brain-Gut Peptides in Both the Hypothalamus and Jejunum of Growing Pigs

Fumonisin B₁ (FB₁) is the most common food-borne mycotoxin produced by the Fusarium species, posing a potential threat to human and animal health. Pigs are more sensitive to FB₁ ingested from feed compared to other farmed livestock. Enzymatic degradation is an ideal detoxification method that has attracted much attention. This study aimed to explore the functional characteristics of the carboxylesterase FumDSB in growing pigs from the perspective of brain–gut regulation. A total of 24 growing pigs were divided into three groups. The control group was fed a basal diet, the FB₁ group was supplemented with FB₁ at 5 mg/kg feed, and the FumDSB group received added FumDSB based on the diet of the FB₁ group. After 35 days of animal trials, samples from the hypothalamus and jejunum were analyzed through HE staining, qRT-PCR and immunohistochemistry. The results demonstrated that the ingestion of FB₁ can reduce the feed intake and weight gain of growing pigs, indicating that several appetite-related brain-gut peptides (including NPY, PYY, ghrelin and obestatin, etc.) play important roles in the anorexia response induced by FB₁. After adding FumDSB as detoxifying enzymes, however, the anorexia effects of FB₁ were alleviated, and the expression and distribution of the corresponding brain-gut peptides exhibited a certain degree of regulation. In conclusion, the addition of FumDSB can reduce the anorexia effects of FB₁ by regulating several brain-gut peptides in both the hypothalamus and the jejunum of growing pigs.

Research Progress on Fumonisin B1 Contamination and Toxicity: A Review

Fumonisin B1 (FB1), belonging to the member of fumonisins, is one of the most toxic mycotoxins produced mainly by Fusarium proliferatum and Fusarium verticillioide. FB1 has caused extensive contamination worldwide, mainly in corn, rice, wheat, and their products, while it also poses a health risk and is toxic to animals and human. It has been shown to cause oxidative stress, endoplasmic reticulum stress, cellular autophagy, and apoptosis. This review focuses on the current stage of FB1 contamination, its toxic effects of acute toxicity, immunotoxicity, organ toxicity, and reproductive toxicity on animals and humans. The potential toxic mechanisms of FB1 are discussed. One of the main aims of the work is to provide a reliable reference strategy for understanding the occurrence and toxicity of FB1.

In vitro interactions of Alternaria mycotoxins, an emerging class of food contaminants, with the gut microbiota: a bidirectional relationship

The human gut microbiota plays an important role in the maintenance of human health. Factors able to modify its composition might predispose the host to the development of pathologies. Among the various xenobiotics introduced through the diet, Alternaria mycotoxins are speculated to represent a threat for human health. However, limited data are currently available about the bidirectional relation between gut microbiota and Alternaria mycotoxins. In the present work, we investigated the in vitro effects of different concentrations of a complex extract of Alternaria mycotoxins (CE; containing eleven mycotoxins; e.g. 0.153 µM alternariol and 2.3 µM altersetin, at the maximum CE concentration tested) on human gut bacterial strains, as well as the ability of the latter to metabolize or adsorb these compounds. Results from the minimum inhibitory concentration assay showed the scarce ability of CE to inhibit the growth of the tested strains. However, the growth kinetics of most of the strains were negatively affected by exposure to the various CE concentrations, mainly at the highest dose (50 µg/mL). The CE was also found to antagonize the formation of biofilms, already at concentrations of 0.5 µg/mL. LC–MS/MS data analysis of the mycotoxin concentrations found in bacterial pellets and supernatants after 24 h incubation showed the ability of bacterial strains to adsorb some Alternaria mycotoxins, especially the key toxins alternariol, alternariol monomethyl ether, and altersetin. The tendency of these mycotoxins to accumulate within bacterial pellets, especially in those of Gram-negative strains, was found to be directly related to their lipophilicity.

Effect of fumonisin B1 on oxidative stress and gene expression alteration of nutrient transporters in porcine intestinal cells

Fumonisin B₁ (FB₁ ) is a common environmental mycotoxin produced by molds such as Fusarium verticillioides. The toxin poses health risks to domestic animals, including pigs, through FB₁ -contaminanted feed. However, the cytotoxicity of FB₁ to porcine intestines has not been fully analyzed. In the present study, the effects of FB₁ on oxidative stress and nutrient transporter-associated genes of the porcine intestinal IPEC-J2 cells were explored. FB₁ decreased IPEC-J2 proliferation but did not trigger reactive oxygen species (ROS) overproduction. Meanwhile, FB₁ reduced the expression levels of the transporters l-type amino acid transporter-1 (y⁺ LAT1), solute carrier family 7 member 1 (SLC7A1), solute carrier family 1 member 5 (ASCT2), and excitatory amino acid carrier 1 (EAAC1); in addition, FB₁ reduced the levels of the fatty acid transporters long-chain fatty acid transport protein 1 (FATP1) and long-chain fatty acid transport protein 4 (FATP4) as well as glucose transporters Na⁺ /glucose cotransporter 1 (SGLT1) and glucose transporter 2 (GLUT2). FB₁ stimulation increased the expression levels of peptide transporter peptide transporter 1 (PepT1) and metal ion transport-related gene zinc transporter 1 (ZNT1). Moreover, metal ion transporter divalent metal transporter 1 (DMT1) expression was depressed by a higher dosage of FB₁ . The data indicate that FB₁ results in aberrant expression of nutrient transporters in IPEC-J2 cells, thereby exerting its toxicity even though it fails to exert ROS-dependent oxidative stress.

Mycotoxin and Gut Microbiota Interactions

The interactions between mycotoxins and gut microbiota were discovered early in animals and explained part of the differences in susceptibility to mycotoxins among species. Isolation of microbes present in the gut responsible for biotransformation of mycotoxins into less toxic metabolites and for binding mycotoxins led to the development of probiotics, enzymes, and cell extracts that are used to prevent mycotoxin toxicity in animals. More recently, bioactivation of mycotoxins into toxic compounds, notably through the hydrolysis of masked mycotoxins, revealed that the health benefits of the effect of the gut microbiota on mycotoxins can vary strongly depending on the mycotoxin and the microbe concerned. Interactions between mycotoxins and gut microbiota can also be observed through the effect of mycotoxins on the gut microbiota. Changes of gut microbiota secondary to mycotoxin exposure may be the consequence of the antimicrobial properties of mycotoxins or the toxic effect of mycotoxins on epithelial and immune cells in the gut, and liberation of antimicrobial peptides by these cells. Whatever the mechanism involved, exposure to mycotoxins leads to changes in the gut microbiota composition at the phylum, genus, and species level. These changes can lead to disruption of the gut barrier function and bacterial translocation. Changes in the gut microbiota composition can also modulate the toxicity of toxic compounds, such as bacterial toxins and of mycotoxins themselves. A last consequence for health of the change in the gut microbiota secondary to exposure to mycotoxins is suspected through variations observed in the amount and composition of the volatile fatty acids and sphingolipids that are normally present in the digesta, and that can contribute to the occurrence of chronic diseases in human. The purpose of this work is to review what is known about mycotoxin and gut microbiota interactions, the mechanisms involved in these interactions, and their practical application, and to identify knowledge gaps and future research needs.

The Compromised Intestinal Barrier Induced by Mycotoxins

Mycotoxins are fungal metabolites that occur in human foods and animal feeds, potentially threatening human and animal health. The intestine is considered as the first barrier against these external contaminants, and it consists of interconnected physical, chemical, immunological, and microbial barriers. In this context, based on in vitro, ex vivo, and in vivo models, we summarize the literature for compromised intestinal barrier issues caused by various mycotoxins, and we reviewed events related to disrupted intestinal integrity (physical barrier), thinned mucus layer (chemical barrier), imbalanced inflammatory factors (immunological barrier), and dysfunctional bacterial homeostasis (microbial barrier). We also provide important information on deoxynivalenol, a leading mycotoxin implicated in intestinal dysfunction, and other adverse intestinal effects induced by other mycotoxins, including aflatoxins and ochratoxin A. In addition, intestinal perturbations caused by mycotoxins may also contribute to the development of mycotoxicosis, including human chronic intestinal inflammatory diseases. Therefore, we provide a clear understanding of compromised intestinal barrier induced by mycotoxins, with a view to potentially develop innovative strategies to prevent and treat mycotoxicosis. In addition, because of increased combinatorial interactions between mycotoxins, we explore the interactive effects of multiple mycotoxins in this review.

Assessment of ionic homeostasis imbalance and cytochrome P450 system disturbance in mice during fumonisin B1 (FB1) exposure

Fumonisin B1 (FB1) is a mycotoxin frequently found in agricultural commodities, and poses a considerable risk for human and animal health. The aim of this study was to investigate the toxic effect of FB1 in mice intestine. Male Kunming mice (n = 40) were treated with FB1 diet for 42 days. Histopathological and biochemical analyses, including ion concentrations, transcription of ATPase subunits and mRNA expression of cytochrome P450s (CYP450s) analyses were performed on duodenum, cecum and colon of mice. The results revealed that FB1 caused histological alterations, including partial shedding of villous epithelial cells and inflammatory cell infiltration. Furthermore, a significant change in Na⁺, K⁺ and Ca²⁺ in serum, and the mRNA expression of ATPase subunits and CYP450s in intestinal tracts were observed in FB1-exposed mice. Our results suggested that FB1 exposure induce histopathological injury via disrupting CYP isoforms transcription and triggering ion homeostasis imbalance in mice intestinal tracts.

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 µg 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.

The effect of moderate-dose aflatoxin B1 and Salmonella Enteritidis infection on intestinal permeability in broiler chickens

The effect of dietary aflatoxin B₁ (AFB₁) and Salmonella Enteritidis infection on intestinal permeability was investigated. Two hundred 1-day-old male Ross 308 broiler chickens were randomly divided into 4 treatments of 5 replicates each (10 birds per replicate), which were fed ad libitum for 3 weeks with the following treatments: control, chickens fed an AFB₁-free diet; AF, chickens fed an AFB₁-contaminated diet at 470 ng/g; SE, chickens fed an AFB₁-free diet and challenged with 10⁸ cfu of S. Enteritidis per bird at 18 days old; AF + SE, chickens fed an AFB₁-contaminated diet and challenged with 10⁸ cfu of S. Enteritidis per bird at 18 days old. At day 21 of age, chicks received an oral gavage dose of fluorescein isothiocyanate dextran (FITC-dextran) to evaluate gastrointestinal leakage. Blood and intestinal samples were collected to evaluate serum biochemistry and total intestinal IgA secretion, respectively. Liver tissues were aseptically collected to assess bacterial invasiveness and for histomorphological studies. The results showed that chickens receiving AFB₁ presented a significant increment (up to 2.4-fold) in serum FITC-dextran concentration (p < 0.05). Nevertheless, S. Enteritidis infection had no additional effect on gastrointestinal leakage. Furthermore, the ingestion of AFB₁ had no impact on the invasive potential of S. Enteritidis. These results suggest that moderate-dose AFB₁ adversely affects intestinal barrier function resulting in increased gut permeability in broiler chickens.

Progress in Mycotoxins Affecting Intestinal Mucosal Barrier Function

Mycotoxins, which are widely found in feed ingredients and human food, can exert harmful effects on animals and pose a serious threat to human health. As the first barrier against external pollutants, the intestinal mucosa is protected by a mechanical barrier, chemical barrier, immune barrier, and biological barrier. Firstly, mycotoxins can disrupt the mechanical barrier function of the intestinal mucosa, by destroying the morphology and tissue integrity of the intestinal epithelium. Secondly, mycotoxins can cause changes in the composition of mucin monosaccharides and the expression of intestinal mucin, which in turn affects mucin function. Thirdly, mycotoxins can cause damage to the intestinal mucosal immune barrier function. Finally, the microbiotas of animals closely interact with ingested mycotoxins. Based on existing research, this article reviews the effects of mycotoxins on the intestinal mucosal barrier and its mechanisms.

The effect of fumonisins producing Fusarium verticillioides on the microbiota in pig caecum

Fumonisin-producing fungal species,Fusarium verticillioides, culture was mixed in the diets of 6 piglets for 9 days (Fumonisin B1[FB1] intake of 17 mg/kg) to investigate whether there is any potential alteration in the caecal bacterial communities between the experimental (withF. verticillioides) and control groups (withoutF. verticillioides). Plate count agar culturing technique was applied to measure the amount of aerobic and anaerobic bacteria,Escherichia coli, coliforms,Lactobacillusspp. andClostridium perfringens. A significant difference was observed between the control and experimental group only in the case of aerobic bacteria on Day 4, 8.60 ± 0.22 compared to 8.06 ± 0.20 (P< 0.05), respectively. Quantitative polymerase chain reaction (qPCR) was performed to estimate the DNA copy number of total bacteria,BacteroidesandPrevotellaspp.,Clostridiumspp.,E. coli,Enterobacteriales,FirmicutesandLactobacillusspp. Significant differences were observed between the control and experimental group regarding total bacteria on Day 2 and Day 6,Firmicuteson Day 2 andE. coliandEnterobacterialeson Day 4. Regarding the entire feeding time, no significant difference between the two groups was found in all species of investigated bacteria by the culturing technique and qPCR after an 8-day exposure. The present research contributes to the understanding of how microbiota responds to the FB1load.

Zearalenone Changes the Diversity and Composition of Caecum Microbiota in Weaned Rabbit

Mycotoxins exhibit several severe effects on intestinal health, but few studies have assessed mycotoxins effect on the intestinal microflora and its repercussions to humans and animals. In this study, we evaluated the effect of zearalenone (ZEA), one of the most harmful mycotoxins on the structure of caecal microbiota in rabbits. Twenty-eight male weaned rabbits were randomly divided into four groups and orally given different concentrations of ZEA (400, 800, and 1600 μg/kg.b.w). Microbial communities in caecum samples of rabbits were analyzed for 16S rRNA by Illumina sequencing through Illumina Miseq platform after being fed for 28 days. The results showed that increasing ZEA doses increased the species richness but did not significantly increased the species diversity of the caecum microbiota in the rabbits. In addition, the caecum microbiota from the samples in different ZEA-treated groups was clustered according to their dosing regimens. At the phylum level, ZEA decreased the abundance of Actinobacteria and significantly increased the abundance of Cyanobacteria, Synergistetes, and Proteobacteria. At the genus level, there were declines in the abundance of Adlercreutzia, Blautia, Desulfitobacter, Lactobacillus, Oxalobacter, and p-75-a5. The decrease of abundance in Lactobacillus, Desulfitobacter, and p-75-a5 was particularly noticeable. In conclusion, zearalenone could increase α-diversity but significantly decrease the abundance of some bacteria with the important metabolic functions. These findings suggested that ZEA could modify the caecum microbiota.

In vitro Interaction between Fumonisin B₁ and the Intestinal Microflora of Pigs

The caecal chyme of pigs was incubated anaerobically in McDougall buffer with and without fumonisin B1 (5 μg/ml) for 0, 24 and 48 h. The plate count agar technique was applied for enumerating the amount of bacteria including aerobic, anaerobic bacteria, coliform, Escherichia coli and Lactobacillus sp. The quantitative polymerase chain reaction was also performed to estimate the number of copies of the total bacteria, Lactobacillus, Bacteroides and Prevotella. No significant differences in the amount of bacterial groups between the experimental (buffer, chyme, and fumonisin B₁) and control 1 groups (buffer + chyme) were observed in both methods. Fumonisin B₁ and hydrolysed fumonisin B₁ concentration were analysed by liquid chromatograghy - mass spectrometry. There was no significant difference in FB₁ concentration between the experimental and the control 2 group (buffer and fumonisin B₁) at 0 h incubation, 5.185 ± 0.174 μg/ml compared with 6.433 ± 0.076 μg/ml. Fumonisin B₁ concentration in the experimental group was reduced to 4.080 ± 0.065 μg/ml at 24 h and to 2.747 ± 0.548 μg/ml at 48 h incubation and was significantly less than that of in the control group. Hydrolysed fumonisin B₁ was detected after 24 h incubation (0.012 ± 0 μg/ml). At 48 h incubation time, hydrolysed fumonisin B₁ concentration was doubled to 0.024 ± 0.004 μg/ml. These results indicate that fumonisin B₁ can be metabolised by caecal microbiota in pigs though the number of studied bacteria did not change.

Intestinal Microbiota Ecological Response to Oral Administrations of Hydrogen-Rich Water and Lactulose in Female Piglets Fed a Fusarium Toxin-Contaminated Diet

The objective of the current experiment was to explore the intestinal microbiota ecological response to oral administrations of hydrogen-rich water (HRW) and lactulose (LAC) in female piglets fed a Fusarium mycotoxin-contaminated diet. A total of 24 individually-housed female piglets (Landrace × large × white; initial average body weight, 7.25 ± 1.02 kg) were randomly assigned to receive four treatments (six pigs/treatment): uncontaminated basal diet (negative control, NC), mycotoxin-contaminated diet (MC), MC diet + HRW (MC + HRW), and MC diet + LAC (MC + LAC) for 25 days. Hydrogen levels in the mucosa of different intestine segments were measured at the end of the experiment. Fecal scoring and diarrhea rate were recorded every day during the whole period of the experiment. Short-chain fatty acids (SCFAs) profiles in the digesta of the foregut and hindgut samples were assayed. The populations of selected bacteria and denaturing gradient gel electrophoresis (DGGE) profiles of total bacteria and methanogenic Archaea were also evaluated. Results showed that Fusarium mycotoxins not only reduced the hydrogen levels in the caecum but also shifted the SCFAs production, and populations and communities of microbiota. HRW treatment increased the hydrogen levels of the stomach and duodenum. HRW and LAC groups also had higher colon and caecum hydrogen levels than the MC group. Both HRW and LAC protected against the mycotoxin-contaminated diet-induced higher diarrhea rate and lower SCFA production in the digesta of the colon and caecum. In addition, the DGGE profile results indicated that HRW and LAC might shift the pathways of hydrogen-utilization bacteria, and change the diversity of intestine microbiota. Moreover, HRW and LAC administrations reversed the mycotoxin-contaminated diet-induced changing of the populations of Escherichia coli (E. coli) and Bifidobacterium in ileum digesta and hydrogen-utilizing bacteria in colon digesta.

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.

Risks for animal health related to the presence of fumonisins, their modified forms and hidden forms in feed

Fumonisins, mycotoxins primarily produced by Fusarium verticillioides and Fusarium proliferatum, occur predominantly in cereal grains, especially in maize. The European Commission asked EFSA for a scientific opinion on the risk to animal health related to fumonisins and their modified and hidden forms in feed. Fumonisin B1 (FB 1), FB 2 and FB 3 are the most common forms of fumonisins in feedstuffs and thus were included in the assessment. FB 1, FB 2 and FB 3 have the same mode of action and were considered as having similar toxicological profile and potencies. For fumonisins, the EFSA Panel on Contaminants in the Food Chain (CONTAM) identified no-observed-adverse-effect levels (NOAELs) for cattle, pig, poultry (chicken, ducks and turkeys), horse, and lowest-observed-adverse-effect levels (LOAELs) for fish (extrapolated from carp) and rabbits. No reference points could be identified for sheep, goats, dogs, cats and mink. The dietary exposure was estimated on 18,140 feed samples on FB 1-3 representing most of the feed commodities with potential presence of fumonisins. Samples were collected between 2003 and 2016 from 19 different European countries, but most of them from four Member States. To take into account the possible occurrence of hidden forms, an additional factor of 1.6, derived from the literature, was applied to the occurrence data. Modified forms of fumonisins, for which no data were identified concerning both the occurrence and the toxicity, were not included in the assessment. Based on mean exposure estimates, the risk of adverse health effects of feeds containing FB 1-3 was considered very low for ruminants, low for poultry, horse, rabbits, fish and of potential concern for pigs. The same conclusions apply to the sum of FB 1-3 and their hidden forms, except for pigs for which the risk of adverse health effect was considered of concern.

Mycotoxin: Its Impact on Gut Health and Microbiota

The secondary metabolites produced by fungi known as mycotoxins, are capable of causing mycotoxicosis (diseases and death) in human and animals. Contamination of feedstuffs as well as food commodities by fungi occurs frequently in a natural manner and is accompanied by the presence of mycotoxins. The occurrence of mycotoxins' contamination is further stimulated by the on-going global warming as reflected in some findings. This review comprehensively discussed the role of mycotoxins (trichothecenes, zearalenone, fumonisins, ochratoxins, and aflatoxins) toward gut health and gut microbiota. Certainly, mycotoxins cause perturbation in the gut, particularly in the intestinal epithelial. Recent insights have generated an entirely new perspective where there is a bi-directional relationship exists between mycotoxins and gut microbiota, thus suggesting that our gut microbiota might be involved in the development of mycotoxicosis. The bacteria-xenobiotic interplay for the host is highlighted in this review article. It is now well established that a healthy gut microbiota is largely responsible for the overall health of the host. Findings revealed that the gut microbiota is capable of eliminating mycotoxin from the host naturally, provided that the host is healthy with a balance gut microbiota. Moreover, mycotoxins have been demonstrated for modulation of gut microbiota composition, and such alteration in gut microbiota can be observed up to species level in some of the studies. Most, if not all, of the reported effects of mycotoxins, are negative in terms of intestinal health, where beneficial bacteria are eliminated accompanied by an increase of the gut pathogen. The interactions between gut microbiota and mycotoxins have a significant role in the development of mycotoxicosis, particularly hepatocellular carcinoma. Such knowledge potentially drives the development of novel and innovative strategies for the prevention and therapy of mycotoxin contamination and mycotoxicosis.

Appropriateness to set a group health-based guidance value for fumonisins and their modified forms

The EFSA Panel on Contaminants in the Food Chain (CONTAM) established a tolerable daily intake (TDI) for fumonisin B1 (FB 1) of 1.0 μg/kg body weight (bw) per day based on increased incidence of megalocytic hepatocytes found in a chronic study with mice. The CONTAM Panel considered the limited data available on toxicity and mode of action and structural similarities of FB 2-6 and found it appropriate to include FB 2, FB 3 and FB 4 in a group TDI with FB 1. Modified forms of FBs are phase I and phase II metabolites formed in fungi, infested plants or farm animals. Modified forms also arise from food or feed processing, and include covalent adducts with matrix constituents. Non-covalently bound forms are not considered as modified forms. Modified forms of FBs identified are hydrolysed FB 1-4 (HFB 1-4), partially hydrolysed FB 1-2 (pHFB 1-2), N-(carboxymethyl)-FB 1-3 (NCM-FB 1-3), N-(1-deoxy-d-fructos-1-yl)-FB 1 (NDF-FB 1), O-fatty acyl FB 1, N-fatty acyl FB 1 and N-palmitoyl-HFB 1. HFB 1, pHFB 1, NCM-FB 1 and NDF-FB 1 show a similar toxicological profile but are less potent than FB 1. Although in vitro data shows that N-fatty acyl FBs are more toxic in vitro than FB 1, no in vivo data were available for N-fatty acyl FBs and O-fatty acyl FBs. The CONTAM Panel concluded that it was not appropriate to include modified FBs in the group TDI for FB 1-4. The uncertainty associated with the present assessment is high, but could be reduced provided more data are made available on occurrence, toxicokinetics and toxicity of FB 2-6 and modified forms of FB 1-4.

Effects of Adding Clostridium sp. WJ06 on Intestinal Morphology and Microbial Diversity of Growing Pigs Fed with Natural Deoxynivalenol Contaminated Wheat

Deoxynivalenol (DON) is commonly detected in cereals, and is a threat to human and animal health. The effects of microbiological detoxification are now being widely studied. A total of 24 pigs (over four months) were randomly divided into three treatments. Treatment A was fed with a basal diet as the control group. Treatment B was fed with naturally DON-contaminated wheat as a negative control group. Treatment C was fed with a contaminated diet that also had Clostridium sp. WJ06, which was used as a detoxicant. Growth performance, relative organ weight, intestinal morphology, and the intestinal flora of bacteria and fungi were examined. The results showed that after consuming a DON-contaminated diet, the growth performance of the pigs decreased significantly (p < 0.05), the relative organ weight of the liver and kidney increased significantly (p < 0.05), and the integrity of the intestinal barrier was also impaired, though the toxic effects of the contaminated diets on growing pigs were relieved after adding Clostridium sp. WJ06. The data from MiSeq sequencing of the 16S ribosomal ribonucleic acid (rRNA) gene and internal transcribed spacer 1 (ITS1) gene suggested that the abundance of intestinal flora was significantly different across the three treatments. In conclusion, the application of Clostridium sp. WJ06 can reduce the toxic effects of DON and adjust the intestinal microecosystem of growing pigs.

Response of Intestinal Bacterial Flora to the Long-term Feeding of Aflatoxin B1 (AFB1) in Mice

In order to investigate the influence of aflatoxin B1 (AFB1) on intestinal bacterial flora, 24 Kunming mice (KM mice) were randomly placed into four groups, which were labeled as control, low-dose, medium-dose, and high-dose groups. They were fed intragastrically with 0.4 mL of 0 mg/L, 2.5 mg/L, 4 mg/L, or 10 mg/L of AFB1 solutions, twice a day for 2 months. The hypervariable region V3 + V4 on 16S rDNA of intestinal bacterial flora was sequenced by the use of a high-flux sequencing system on a Miseq Illumina platform; then, the obtained sequences were analyzed. The results showed that, when compared with the control group, both genera and phyla of intestinal bacteria in the three treatment groups decreased. About one third of the total genera and one half of the total phyla remained in the high-dose group. The dominant flora were Lactobacillus and Bacteroides in all groups. There were significant differences in the relative abundance of intestinal bacterial flora among groups. Most bacteria decreased as a whole from the control to the high-dose groups, but several beneficial and pathogenic bacterial species increased significantly with increasing dose of AFB1. Thus, the conclusion was that intragastric feeding with 2.5~10 mg/mL AFB1 for 2 months could decrease the majority of intestinal bacterial flora and induce the proliferation of some intestinal bacteria flora.

1H NMR and MVA metabolomic profiles of urines from piglets fed with boluses contaminated with a mixture of five mycotoxins

Metabolic profile of urine from piglets administered with single boluses contaminated with mycotoxin mixture (deoxynivalenol, aflatoxin B1, fumonisin B1, zearalenone, and ochratoxin A) were studied by 1H NMR spectroscopy and chemometrics (PCA, PLS-DA, and OPLS-DA). The mycotoxin levels were close to the established maximum and guidance levels for animal feed (2003/100/EC and 2006/576/EC). Urine samples were obtained from four groups of four piglets before (control, C) or within 24 h (treated, T) after receiving a contaminated boluses with increasing doses of mycotoxins (boluses 1-4). For the two highest dose groups, the urines were collected also after one week of wash out (W). For the two lowest doses groups no significant differences between the C and T samples were observed. By contrast, for the two highest doses groups the T urines separated from the controls for a higher relative content of creatinine, p-cresol glucuronide and phenyl acetyl glycine and lower concentration of betaine and TMAO. Interestingly, a similar profile was found for both W and T urines suggesting, at least for the highest doses used, serious alteration after a single bolus of mycotoxin mixture.

Reduction of Fumonisin Toxicity by Extrusion and Nixtamalization (Alkaline Cooking)

Fumonisins are mycotoxins found in corn. They are toxic to animals and cause cancer in rodents and neural tube defects in LM/Bc mice. Reducing their concentrations in corn-based foods is therefore desirable. Chemical analysis or in vitro bioassays of food extracts might not detect toxic fumonisin reaction products that are unknown or unextractable from food matrices, thus potentially underestimating in vivo toxicity. The effectiveness of two common cooking methods, extrusion and nixtamalization (alkaline cooking), to reduce the toxicity of fumonisin-contaminated corn grits (extrusion) and whole kernel corn (nixtamalization) was shown by means of rat feeding bioassays using fumonisin-specific kidney effects as indicators of potential toxicity. A third bioassay showed that in contrast to fumonisin B₁ (FB₁), hydrolyzed fumonisin B₁ (HFB₁; formed from FB₁ during nixtamalization) did not cause neural tube defects in LM/Bc mice. The findings indicate that extrusion and nixtamalization reduce the potential toxicity of FB₁-contaminated corn.

Activity of Zearalenone in the Porcine Intestinal Tract

This study demonstrates that low doses (somewhat above the No Observed Adverse Effect Level, NOAEL) of the mycoestrogen zearalenone (ZEN) and its metabolites display multispecificity towards various biological targets in gilts. The observed responses in gilts were surprising. The presence of ZEN and zearalenols (ZELs) did not evoke a response in the porcine gastrointestinal tract, which was attributed to dietary tolerance. Lymphocyte proliferation was intensified in jejunal mesenteric lymph nodes, and lymphocyte counts increased in the jejunal epithelium with time of exposure. In the distal digestive tract, fecal bacterial counts decreased, the activity of fecal bacterial enzymes and lactic acid bacteria increased, and cecal water was characterized by higher genotoxicity. The accompanying hyperestrogenism led to changes in mRNA activity of selected enzymes (cytochrome P450, hydroxysteroid dehydrogenases, nitric oxide synthases) and receptors (estrogen and progesterone receptors), and it stimulated post-translational modifications which play an important role in non-genomic mechanisms of signal transmission. Hyperestrogenism influences the regulation of the host's steroid hormones (estron, estradiol and progesteron), it affects the virulence of bacterial genes encoding bacterial hydroxysteroid dehydrogenases (HSDs), and it participates in detoxification processes by slowing down intestinal activity, provoking energy deficits and promoting antiporter activity at the level of enterocytes. In most cases, hyperestrogenism fulfils all of the above roles. The results of this study indicate that low doses of ZEN alleviate inflammatory processes in the digestive system, in particular in the proximal and distal intestinal tract, and increase body weight gains in gilts.

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.

Impact of two mycotoxins deoxynivalenol and fumonisin on pig intestinal health

Mycotoxins are secondary metabolites of fungi that grow on a variety of substrates. Due to their high consumption of cereals and their sensitivity, pigs are highly impacted by the presence of mycotoxins. At the European level, regulations and recommendations exist for several mycotoxins in pig feed. Among these toxins, fumonisin B₁ (FB₁), and deoxynivalenol (DON) have a great impact on the intestine and the immune system. Indeed, the intestine is the first barrier to food contaminants and can be exposed to high concentrations of mycotoxins upon ingestion of contaminated feed. FB₁ and DON alter the intestinal barrier, impair the immune response, reduce feed intake and weight gain. Their presence in feed increases the translocation of bacteria; mycotoxins can also impair the immune response and enhance the susceptibility to infectious diseases. In conclusion, because of their effect on the intestine, FB₁ and DON are a major threat to pig health, welfare and performance.

Impact of mycotoxin on immune response and consequences for pig health

Mycotoxins are fungal secondary metabolites detected in many agricultural commodities, especially cereals. Due to their high consumption of cereals, pigs are exposed to these toxins. In the European Union, regulations and/or recommendations exist in pig feed for aflatoxins, ochratoxin A, fumonisins, zearalenone, and trichothecenes, deoxynivalenol and T-2 toxin. These mycotoxins have different toxic effects, but they all target the immune system. They have immunostimulatory or immunosuppressive effects depending on the toxin, the concentration and the parameter investigated. The immune system is primarily responsible for defense against invading organisms. The consequences of the ingestion of mycotoxin-contaminated feed are an increased susceptibility to infectious diseases, a reactivation of chronic infection and a decreased vaccine efficacy. In this review we summarized the data available on the effect of mycotoxins on the immune system and the consequences for pig health.

Gastrointestinal Degradation of Fumonisin B₁ by Carboxylesterase FumD Prevents Fumonisin Induced Alteration of Sphingolipid Metabolism in Turkey and Swine

The mycotoxin fumonisin B₁ (FB₁) is a frequent contaminant of feed and causes various adverse health effects in domestic animals. Hence, effective strategies are needed to prevent the impact of fumonisins on livestock productivity. Here we evaluated the capability of the fumonisin carboxylesterase FumD to degrade FB₁ to its less toxic metabolite hydrolyzed FB₁ (HFB₁) in the gastrointestinal tract of turkeys and pigs. First, an ex vivo pig model was used to examine the activity of FumD under digestive conditions. Within 2 h of incubation with FumD, FB₁ was completely degraded to HFB₁ in the duodenum and jejunum, respectively. To test the efficacy of the commercial application of FumD (FUMzyme) in vivo, female turkeys (n = 5) received either basal feed (CON), fumonisin-contaminated feed (15 mg/kg FB₁+FB₂; FB) or fumonisin-contaminated feed supplemented with FUMzyme (15 U/kg; FB+FUMzyme) for 14 days ad libitum. Addition of FUMzyme resulted in significantly decreased levels of FB₁ in excreta, whereas HFB₁ concentrations were significantly increased. Compared to the FB group (0.24 ± 0.02), the mean serum sphinganine-to-sphingosine (Sa/So) ratio was significantly reduced in the FB+FUMzyme group (0.19 ± 0.02), thus resembling values of the CON group (0.16 ± 0.02). Similarly, exposure of piglets (n = 10) to 2 mg/kg FB₁+FB₂ for 42 days caused significantly elevated serum Sa/So ratios (0.39 ± 0.15) compared to the CON group (0.14 ± 0.01). Supplementation with FUMzyme (60 U/kg) resulted in gastrointestinal degradation of FB₁ and unaffected Sa/So ratios (0.16 ± 0.02). Thus, the carboxylesterase FumD represents an effective strategy to detoxify FB₁ in the digestive tract of turkeys and pigs.

Fumonisins affect the intestinal microbial homeostasis in broiler chickens, predisposing to necrotic enteritis

Fumonisins (FBs) are mycotoxins produced by Fusarium fungi. This study aimed to investigate the effect of these feed contaminants on the intestinal morphology and microbiota composition, and to evaluate whether FBs predispose broilers to necrotic enteritis. One-day-old broiler chicks were divided into a group fed a control diet, and a group fed a FBs contaminated diet (18.6 mg FB1+FB2/kg feed). A significant increase in the plasma sphinganine/sphingosine ratio in the FBs-treated group (0.21 ± 0.016) compared to the control (0.14 ± 0.014) indicated disturbance of the sphingolipid biosynthesis. Furthermore, villus height and crypt depth of the ileum was significantly reduced by FBs. Denaturing gradient gel electrophoresis showed a shift in the microbiota composition in the ileum in the FBs group compared to the control. A reduced presence of low-GC containing operational taxonomic units in ileal digesta of birds exposed to FBs was demonstrated, and identified as a reduced abundance of Candidatus Savagella and Lactobaccilus spp. Quantification of total Clostridium perfringens in these ileal samples, previous to experimental infection, using cpa gene (alpha toxin) quantification by qPCR showed an increase in C. perfringens in chickens fed a FBs contaminated diet compared to control (7.5 ± 0.30 versus 6.3 ± 0.24 log10 copies/g intestinal content). After C. perfringens challenge, a higher percentage of birds developed subclinical necrotic enteritis in the group fed a FBs contaminated diet as compared to the control (44.9 ± 2.22% versus 29.8 ± 5.46%).

The effect of experimental fusarium mycotoxicosis on microbiota diversity in porcine ascending colon contents

The objective of the study was to determine the effect of exposure of pigs to the Fusarium mycotoxins zearalenone (ZEN) and deoxynivalenol (DON), administered together and separately, on the colon microbiota. An experiment was conducted for 42 days on gilts, randomly assigned to four groups and administered either ZEN, DON, ZEN+DON, or a placebo. The number of aerobic mesophilic bacteria, yeasts, molds, anaerobic Clostridium perfringens, fecal streptococci, Enterobacteriaceae, Escherichia coli, and lactic acid bacteria (LAB) were determined in the contents of the ascending colon. The influence of mycotoxins on the functional diversity of the colonic microbiota was assessed using EcoPlate tests (Biolog). Analysis revealed the predominance of LAB in all groups of pigs. Zearalenone, administered separately and together with DON, was found to have an adverse effect on mesophilic aerobic bacteria, but only after long exposure to this mycotoxin. During the six weeks of the experiment, the concentration of C. perfringens, E. coli, and other bacteria in the family Enterobacteriaceae was most considerably reduced in the experimental groups exposed to zearalenone, both separately and together with DON. Mycotoxins also affected the functional biodiversity of microorganisms. Both Shannon’s diversity index and the number of catabolized substrates in Biolog plate (the R index) were much higher in the group subjected to mixed mycotoxicosis.

The impact of Fusarium mycotoxins on human and animal host susceptibility to infectious diseases

Contamination of food and feed with mycotoxins is a worldwide problem. At present, acute mycotoxicosis caused by high doses is rare in humans and animals. Ingestion of low to moderate amounts of Fusarium mycotoxins is common and generally does not result in obvious intoxication. However, these low amounts may impair intestinal health, immune function and/or pathogen fitness, resulting in altered host pathogen interactions and thus a different outcome of infection. This review summarizes the current state of knowledge about the impact of Fusarium mycotoxin exposure on human and animal host susceptibility to infectious diseases. On the one hand, exposure to deoxynivalenol and other Fusarium mycotoxins generally exacerbates infections with parasites, bacteria and viruses across a wide range of animal host species. Well-known examples include coccidiosis in poultry, salmonellosis in pigs and mice, colibacillosis in pigs, necrotic enteritis in poultry, enteric septicemia of catfish, swine respiratory disease, aspergillosis in poultry and rabbits, reovirus infection in mice and Porcine Reproductive and Respiratory Syndrome Virus infection in pigs. However, on the other hand, T-2 toxin has been shown to markedly decrease the colonization capacity of Salmonella in the pig intestine. Although the impact of the exposure of humans to Fusarium toxins on infectious diseases is less well known, extrapolation from animal models suggests possible exacerbation of, for instance, colibacillosis and salmonellosis in humans, as well.

Evaluation of an oral subchronic exposure of deoxynivalenol on the composition of human gut microbiota in a model of human microbiota-associated rats

BACKGROUND

Deoxynivalenol (DON), a mycotoxin produced by Fusarium species, is one of the most prevalent mycotoxins present in cereal crops worldwide. Due to its toxic properties, high stability and prevalence, the presence of DON in the food chain represents a health risk for both humans and animals. The gastrointestinal microbiota represents potentially the first target for these food contaminants. Thus, the effects of mycotoxins on the human gut microbiota is clearly an issue that needs to be addressed in further detail. Using a human microbiota-associated rat model, the aim of the present study was to evaluate the impact of a chronic exposure of DON on the composition of human gut microbiota.

METHODOLOGY/PRINCIPAL FINDINGS

Four groups of 5 germ free male rats each, housed in 4 sterile isolators, were inoculated with a different fresh human fecal flora. Rats were then fed daily by gavage with a solution of DON at 100 µg/kg bw for 4 weeks. Fecal samples were collected at day 0 before the beginning of the treatment; days 7, 16, 21, and 27 during the treatment; and 10 days after the end of the treatment at day 37. DON effect was assessed by real-time PCR quantification of dominant and subdominant bacterial groups in feces. Despite a different intestinal microbiota in each isolator, similar trends were generally observed. During oral DON exposure, a significant increase of 0.5 log10 was observed for the Bacteroides/Prevotella group during the first 3 weeks of administration. Concentration levels for Escherichia coli decreased at day 27. This significant decrease (0.9 log10 CFU/g) remained stable until the end of the experiment.

CONCLUSIONS/SIGNIFICANCE

We have demonstrated an impact of oral DON exposure on the human gut microbiota composition. These findings can serve as a template for risk assessment studies of food contaminants on the human gut microbiota.