Aflatoxin, fumonisin and Shiga toxin-producing Escherichia coli infections in calves and the effectiveness of Celmanax®/Dairyman's Choice™ applications to eliminate morbidity and mortality losses

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.

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.

Effects of post-weaning supplementation of immunomodulatory feed ingredient on circulating cytokines and microbial populations in programmed fed beef heifers

The objective was to determine the effects of an immunomodulatory feed ingredient following weaning on cytokine expression and fecal microbial populations of heifers. Commercial Angus heifers (n = 72) were weaned (227 ± 7 d of age), blocked by BW (n = 9 blocks) and randomly assigned to one of 2 pens per block. Pens within weight block (4 heifers/pen) were then randomly assigned to treatments. Heifers were fed twice daily from d 0-60 (to gain 0.75kg/day) and top-dressed with either 18g/heifer/d of the immunomodulatory feed ingredient (Celmanax; Arm and Hammer Animal Nutrition, Princeton, NJ, USA; CEL) or corn-germ meal (CON). Blood samples were collected on d 0, 15, 30, 45, 60 and fecal grab samples on d 0 of the feeding trial. After d 60, two heifers per pen (n=32) were randomly selected for a transportation challenge. Serum samples were collected at h 0, 4, 8, 12 and fecal grab samples at h -24, 0, 24 and 7d post-challenge. Blood samples were analyzed for interferonγ (IFNγ), interleukin-8 (IL-8), and haptoglobin (HP) using commercially available ELISA kits and qRT-PCR for genes of interest associated with cytokine expression. Fecal samples were enumerated for Clostridia and E. coli using selective media (≤ 5 isolates from each media/sample), tested to determine if they were C. perfringens or pathogenic E. coli, and then enriched for detection of Salmonella. Data was analyzed via ANOVA. During the feeding trial, HP was reduced (P = 0.018) in CEL compared to CON at d 15, 45, and 60, while IFNγ and IL-8 did not differ (P > 0.080) between treatments. All cytokines were decreased (P < 0.001) in CEL compared to CON during the challenge. During the feeding trial, HP mRNA was increased (P = 0.045) in CEL compared to CON at d 30 and 60. Similarly, IFNγ mRNA was increased (P = 0.040) in CEL compared to CON, however, other genes of interest did not differ (P > 0.172). Both C. perfringens and total E. coli counts were decreased (P = 0.036) in CEL compared to CON at 24h after the start of the transportation challenge. Clostridia and pathogenic E. coli counts did not differ (P = 0.941) between treatments. Total Clostridia and E. coli counts were increased (P < 0.014) 24h post-challenge. All microbial populations, except pathogenic E. coli, observed decreased (P ≤ 0.009) counts from 24h to 7d post-challenge. Overall, Celmanax supplementation decreased circulating cytokines, and altered microbial populations and gene expression, thus, may serve a role in preparing animals to better cope with immunological challenges.

Deepoxy-deoxynivalenol (DOM-1), a derivate of deoxynivalenol (DON), exhibits less toxicity on intestinal barrier function, Campylobacter jejuni colonization and translocation in broiler chickens

Background

Intestinal epithelial cells are challenged by mycotoxins and many bacterial pathogens. It was previously shown that the mycotoxin deoxynivalenol (DON) as well as Campylobacter (C.) jejuni have a negative impact on gut integrity. Recently, it was demonstrated that DON increased the load of C. jejuni in the gut and inner organs. Based on this finding, it was hypothesized the DON metabolite (deepoxy-deoxynivalenol, DOM-1) should be able to reduce the negative effects of DON on colonization and translocation of C. jejuni in broilers, since it lacks the epoxide ring, which is responsible for the toxicity of DON.

Methods

A total of 180 broiler chickens were housed in floor pens on wood shavings with feed and water provided ad libitum. Birds were divided into six groups (n = 30 with 5 replicates/group): 1. Control, 2. DOM-1, 3. DON, 4. DOM-1 + C. jejuni, 5. DON + C. jejuni, 6. C. jejuni. At day 14, birds of groups 4, 5 and 6 were orally inoculated via feeding tube (gavage) with 1-ml of a PBS suspension containing 1 × 10⁸ CFU of C. jejuni NCTC 12744. The performance parameters: body weight (BW), body weight gain (BWG), and feed intake of the birds were determined. At 7, 14, and 21 days post infection, samples from liver, spleen, duodenum, jejunum and cecum were aseptically collected and processed for bacteriological investigations. Finally, at each killing time point, segments of duodenum, jejunum and cecum were harvested and prepared for Ussing chamber studies to measure the paracellular mannitol fluxes.

Results

A significant decrease in body weight was observed for chickens receiving the DON diet with or without C. jejuni compared to the other groups. Furthermore, it was found that the co-exposure of birds to DON and C. jejuni resulted in a higher C. jejuni load not only in the gut but also in liver and spleen due to increased paracellular permeability of the duodenum, jejunum and cecum. On the contrary, DOM-1 supplementation in the feed improved the birds’ performance and led to a better feed conversion ratio throughout the trial. Furthermore, DOM-1 did not negatively affect gut permeability and decreased the C. jejuni counts in the intestine and internal organs.

Conclusion

Altogether, the presence of DOM-1 in the feed as a result of the enzymatic biotransformation of DON leads to a lower C. jejuni count in the intestine and better feed conversion ratio. Moreover, this study demonstrates that the detoxification product of DON, DOM-1, does not have negative effects on the gastrointestinal tract and reduces the Campylobacter burden in chickens and also the risk for human infection.

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.

Probiotics and potential applications for alternative poultry production systems

Concerns over animal welfare continue to be a critical component of law and policies associated with commercial food animal production. Social and market pressures are the driving forces behind the legislation and result in the change of poultry production management systems. As a result, the movement toward cage-free and aviary-based egg production systems has become standard practices. Cage-based systems being replaced by alternative methods that offer a suitable housing environment to meet or exceed poultry welfare needs and require different management, including the ban of antibiotics in poultry diets. For broiler production, pasture- raised and free-range management systems have become more popular. However, challenges remain from exposure to disease-causing organisms and foodborne pathogens in these environments. Consequently, probiotics can be supplemented in poultry diets as commercial feed additives. The present review discusses the impacts of these probiotics on the performance of alternative poultry production systems for improving food safety and poultry health by mitigating pathogenic organisms and improving egg and meat quality and production.

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.

Nontoxic-dose deoxynivalenol aggravates lipopolysaccharides-induced inflammation and tight junction disorder in IPEC-J2 cells through activation of NF-κB and LC3B

Lipopolysaccharide (LPS) is the key factor in various intestinal inflammation which could disrupt the epithelial barrier function. Deoxynivalenol (DON), a well-known mycotoxin, can induce intestinal injury. However, the combined enterotoxicity of LPS and DON has rarely been studied. In this study, IPEC-J2 cell monolayers were exposed to LPS and nontoxic-dose DON for 12 and 24 h to investigate the effects of DON on LPS-induced inflammatory response and tight junction variation, and specific inhibitor and CRISPR-Cas9 were used to explore the underlying mechanisms. Our results showed that nontoxic-dose DON aggravated LPS-induced cellular inflammatory response, reflecting on more significant changes of inflammatory cytokines mRNA expression, higher protein expression of NOD-like receptor protein 3 (NLRP3) and procaspase-1. Moreover, nontoxic-dose DON aggravated LPS-induced mRNA and protein expression decreased, and distribution confused of tight junction proteins. We found that DON further enhanced LPS-induced phosphorylation and nucleus translocation of p65, and expression of LC3B-Ⅱ. NF-κB inhibitor and CRISPR-Cas9-mediated knockout of LC3B attenuated the effects of combination which indicated nontoxic-dose DON aggravated LPS-induced intestinal inflammation and tight junction disorder through activating NF-κB signaling pathway and autophagy-related protein LC3B. It further warns that ingesting low doses of mycotoxins may exacerbate the effects of intestinal pathogens on the body.

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Nontoxic-dose DON aggravates LPS-induced cellular inflammatory response in IPEC-J2 cell monolayers.

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Nontoxic-dose DON aggravates LPS-induced decrease and distribution disorder of tight junction in IPEC-J2 cell monolayers.

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Nontoxic-dose DON aggravates LPS-induced inflammatory response and tight junction disorder by activating NF-κB and LC3B.

Type III Secretion Effectors with Arginine N-Glycosyltransferase Activity

Type III secretion systems are used by many Gram-negative bacterial pathogens to inject proteins, known as effectors, into the cytosol of host cells. These virulence factors interfere with a diverse array of host signal transduction pathways and cellular processes. Many effectors have catalytic activities to promote post-translational modifications of host proteins. This review focuses on a family of effectors with glycosyltransferase activity that catalyze addition of N-acetyl-d-glucosamine to specific arginine residues in target proteins, leading to reduced NF-κB pathway activation and impaired host cell death. This family includes NleB from Citrobacter rodentium, NleB1 and NleB2 from enteropathogenic and enterohemorrhagic Escherichia coli, and SseK1, SseK2, and SseK3 from Salmonella enterica. First, we place these effectors in the general framework of the glycosyltransferase superfamily and in the particular context of the role of glycosylation in bacterial pathogenesis. Then, we provide detailed information about currently known members of this family, their role in virulence, and their targets.

Lactobacillus rhamnosus GG modulates gastrointestinal absorption, excretion patterns, and toxicity in Holstein calves fed a single dose of aflatoxin B1

The aim of the present study was to evaluate the effects of Lactobacillus rhamnosus GG (LGG; ATCC 53013) on growth performance and hepatotoxicity in calves fed a single dose of aflatoxin B₁ (AFB₁) and to investigate the absorption, distribution, and elimination of AFB₁ and the hydroxylated metabolite aflatoxin M₁ (AFM₁) in rumen fluid, blood, and excretions. Twenty-four male Holstein calves were blocked for body weight and age and were randomly assigned to 1 of 3 treatment groups: (1) untreated control, (2) treated with 4.80 mg of AFB₁ (AFB₁ only), or (3) treated with 1 × 10¹⁰ cfu of LGG suspension and 4.80 mg of AFB₁ (AFB₁ plus LGG). The calves received LGG suspension in 50 mL of phosphate-buffered saline daily via oral administration for 14 d before and on the day they received a single oral dose of AFB₁. Body weight was recorded at the beginning of the study (before LGG administration), at the day of AFB₁ administration, and at the end of the trial. Rumen fluid, blood, urine, and feces samples were collected continuously for 96 h after AFB₁ administration. Average daily gain (ADG) and plasma biochemical parameters were analyzed, and concentrations of AFB₁ and AFM₁ in the samples were determined for monitoring excretion pattern and toxicokinetics. The results showed that ADG was lower in AFB₁-treated animals; LGG administration partially mitigated the decrease in ADG (0.85 ± 0.08 vs. 0.76 ± 0.18 kg of gain/d). The AFB₁ treatment increased plasma aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase levels. Administration of LGG alleviated the AFB₁-induced increase in plasma enzymes activity. The excretion patterns of AFB₁ and AFM₁ were surprisingly regular; toxins were rapidly detected in all samples after a single oral dose of AFB₁, and the peak of toxins concentrations was sequentially reached in rumen fluid, plasma, urine, and feces (except AFM₁ in rumen fluid), followed by an exponential decrease. The excretion curves showed that AFB₁ and AFM₁ concentrations were the highest in feces and urine, respectively. Administration of LGG decreased the concentrations of free AFB₁ and AFM₁ in rumen fluid and reduced the release of toxins into plasma and urine. Toxicokinetic parameters (except for the time of maximum concentration and the terminal half-life) were reduced by LGG administration. In conclusion, the absorption, distribution, and excretion of AFB₁ and AFM₁ were rapid in calves fed a single dose of AFB₁. Urine was the main route for the excretion of AFM₁, and the clearance pattern from the peak of concentration was well fitted by exponential decreasing function. Administration of LGG reduced the absorption of AFB₁ in the gastrointestinal tract by increasing the excretion via the feces, thus alleviating the hepatotoxic effect of AFB₁.

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.

Effects of Mycotoxins on mucosal microbial infection and related pathogenesis

Mycotoxins are fungal secondary metabolites detected in many agricultural commodities and water-damaged indoor environments. Susceptibility to mucosal infectious diseases is closely associated with immune dysfunction caused by mycotoxin exposure in humans and other animals. Many mycotoxins suppress immune function by decreasing the proliferation of activated lymphocytes, impairing phagocytic function of macrophages, and suppressing cytokine production, but some induce hypersensitive responses in different dose regimes. The present review describes various mycotoxin responses to infectious pathogens that trigger mucosa-associated diseases in the gastrointestinal and respiratory tracts of humans and other animals. In particular, it focuses on the effects of mycotoxin exposure on invasion, pathogen clearance, the production of cytokines and immunoglobulins, and the prognostic implications of interactions between infectious pathogens and mycotoxin exposure.

Harnessing microbiome and probiotic research in sub-Saharan Africa: recommendations from an African workshop

To augment capacity-building for microbiome and probiotic research in Africa, a workshop was held in Nairobi, Kenya, at which researchers discussed human, animal, insect, and agricultural microbiome and probiotics/prebiotics topics. Five recommendations were made to promote future basic and translational research that benefits Africans.

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.