Mycotoxin fumonisin B1 alters the cytokine profile and decreases the vaccinal antibody titer in pigs

Comparison Study of Two Fumonisin-Degrading Enzymes for Detoxification in Piglets

Fumonisins (FBs), particularly fumonisin B1 (FB1) and fumonisin B2 (FB2) produced mainly by Fusarium verticillioide and Fusarium proliferatum, are common contaminants in animal feed and pose a serious threat to both animal and human health. The use of microbial enzymes to efficiently and specifically convert fumonisins into non-toxic or low-toxic metabolites has emerged as the most promising approach. However, most of the available enzymes have only been evaluated in vitro and lack systematic evaluation in vivo. In this study, the detoxification efficacy of two carboxylesterases, FumD (FUMzyme®) and FumDSB, was evaluated comparatively in piglets. The results show that feeding piglets 4.4 mg/kg FBs-contaminated diets for 32 days did not significantly affect the average daily gain, organ indices, and immunoglobulins of the piglets. However, a significant reduction (21.2%) in anti-inflammatory cytokine interleukin-4 was observed in the FBs group, and supplementation with FUMzyme® and FumDSB significantly increased interleukin-4 by 62.1% and 28.0%, respectively. In addition, FBs-contaminated diets resulted in a 3-fold increase in the serum sphinganine/sphingosine (Sa/So) ratio, which is a specific biomarker that has been used to accurately reflect fumonisin levels. The serum Sa/So ratio was significantly reduced by 48.8% after the addition of FUMzyme®, and was insignificantly reduced by 8.2% in the FumDSB group. These results suggested that FUMzyme was more effective than FumDSB in mitigating FBs toxicity in piglets by down-regulating the Sa/So ratio.

Foodborne Diseases Due to Underestimated Hazard of Joint Mycotoxin Exposure at Low Levels and Possible Risk Assessment

The subject of this review paper is to evaluate the underestimated hazard of multiple mycotoxin exposure of animals/humans for the appearance of foodborne ailments and diseases. The significance of joint mycotoxin interaction in the development of foodborne diseases is discussed, and appropriate conclusions are made. The importance of low feed/food levels of some target mycotoxins co-contaminations in food and feedstuffs for induction of target foodborne mycotoxicoses is also studied in the available literature. The appropriate hygiene control and the necessary risk assessment in regard to possible hazards for animals and humans are also discussed, and appropriate suggestions are made. Some internationally recognized prophylactic measures, management of the risk, and the necessity of elaboration of new international regulations in regard to the maximum permitted levels are also carefully discussed and analysed in the cases of multiple mycotoxin contaminations. The necessity of harmonization of mycotoxin regulations and control measures at international levels is also discussed in order to facilitate food trade between the countries and to ensure global food safety.

Efficacy of Feed Additive Containing Bentonite and Enzymatically Hydrolyzed Yeast on Intestinal Health and Growth of Newly Weaned Pigs under Chronic Dietary Challenges of Fumonisin and Aflatoxin

This study aimed to investigate the efficacy of a feed additive containing bentonite and enzymatically hydrolyzed yeast on the intestinal health and growth of newly weaned pigs under chronic dietary exposure to fumonisin and aflatoxin. Newly weaned pigs were randomly allotted to one of four possible treatments: a control diet of conventional corn; a diet of corn contaminated with fumonisin and aflatoxin; a diet of mycotoxin-contaminated corn with 0.2% of feed additive; and a diet of mycotoxin contaminated corn with 0.4% of feed additive. We observed lower average weight gain and average daily feed intake in pigs that were fed only mycotoxin-contaminated corn compared to the control group. Feed additive supplementation linearly increased both average weight gain and feed intake, as well as tumor necrosis factor-alpha. In the jejunum, there was an observed decrease in immunoglobulin A and an increase in claudin-1. Additionally, feed additive supplementation increased the villus height to crypt depth ratio compared to the control. In conclusion, feed additives containing bentonite and enzymatically hydrolyzed yeast could mitigate the detrimental effects of mycotoxins on the growth performance of newly weaned pigs by improving intestinal integrity and positively modulating immune response.

The natural occurrence, toxicity mechanisms and management strategies of Fumonisin B1：A review

Fumonisin B1 (FB1) contaminates various crops, causing huge losses to agriculture and livestock worldwide. This review summarizes the occurrence regularity, toxicity, toxic mechanisms and management strategies of FB1. Specifically, FB1 contamination is particularly serious in developing countries, humid and hot regions. FB1 exposure can produce different toxic effects on the nervous system, respiratory system, digestive system and reproductive system. Furthermore, FB1 can also cause systemic immunotoxicity. The mechanism of toxic effects of FB1 is to interfere with the normal pathway of sphingolipid de novo biosynthesis by acting as a competitive inhibitor of ceramide synthase. Meanwhile, the toxic products of sphingolipid metabolic disorders can cause oxidative stress and apoptosis. FB1 also often causes feed contamination by mixing with other mycotoxins, and then exerts combined toxicity. For detection, lateral flow dipstick technology and enzyme linked immunosorbent assay are widely used in the detection of FB1 in commercial feeds, while mainstream detection methods such as high performance liquid chromatography and liquid chromatography-mass spectrometry are widely used in the laboratory theoretical study of FB1. For purification means of FB1, some natural plant extracts (such as Zingiber officinale and Litsea Cubeba essential oil) and their active compounds have been proved to inhibit the toxic effects of FB1 and protect livestock due to their antifungal and antioxidant effects. Natural plant extract has the advantages of high efficiency, low cost and no contamination residue. This review can provide information for comprehensive understanding of FB1, and provide reference for formulating reasonable treatment and management strategies in livestock production.

Fusarium verticillioides of maize plant: Potentials of propitious phytomicrobiome as biocontrol agents

Disease outbreaks have been recorded due to exposure to Fusarium verticillioides and fumonisin, a mycotoxin produced by this fungus. F. verticillioides is a fungal pathogen of maize that causes infections, such as wilting and rotting, while contact with its fumonisin derivative manifests in the form of mild to severe illnesses in humans and animals. Maize infection by F. verticillioides causes loss or reduction in expected crop yield, thereby influencing households and nations' economies. While several efforts have been made to control the pathogenic fungus and its occurrence in the environment, it remains a challenge in agriculture, particularly in maize production. Several microorganisms which are plant-associated, especially those associated with the rhizosphere niche have been noted to possess antagonistic effects against F. verticillioides. They can inhibit the pathogen and tackle its debilitating effects on plants. Hence this study reviews the use of rhizosphere-associated biocontrol agents, such as Bacillus spp., Pseudomonas, Enterobacter, and Microbacterium oleivorans which forms part of the phytomicrobiome in other to prevent and control this toxicogenic fungus. These microorganisms were found to not only be effective in controlling its occurrence on maize plants but are environmentally safe and promote crop yield.

Vaccination Failures in Pigs-The Impact of Chosen Factors on the Immunisation Efficacy

Infectious diseases that often lead to economic losses still pose a severe problem in the pig production sector. Because of increasing restrictions on antibiotic usage, vaccines may become one of the major approaches to controlling infectious diseases; much research has proved that they could be very efficient. Nevertheless, during their life, pigs are exposed to various factors that can interfere with vaccination efficacy. Therefore, in the present paper, we reviewed the influence of chosen factors on the pig immunisation process, such as stress, faecal microbiota, host genetics, the presence of MDAs, infections with immunosuppressive pathogens, and treatment with antibiotics and mycotoxins. Many of them turned out to have an adverse impact on vaccine efficacy.

Effects of aflatoxin B1 on growth performance, antioxidant status, immune response, and pro-inflammatory cytokine mRNA expression in ISA chicks

The research evaluated the effects of Aflatoxin B1 on growth performance, antioxidant status, immune response, and pro-inflammatory cytokine mRNA expression in ISA chicks. In total, 240 7-day-old ISA chicks were randomly assigned to four treatment groups. The control group comprised chicks fed a basal diet. The aflatoxin (AFB₁)-treatment groups (T1, T2, and T3) comprised chicks fed the basal diet supplemented with AFB₁ at concentrations of 5, 8, and 10 μg/kg, respectively. The growth performance, antioxidant status, immune responses, and pro-inflammatory cytokine mRNA expression in all groups were measured. In the T1 treatment group (receiving the lowest AFB₁ dose), a reduction in the Newcastle disease virus antibody (NDV-Ab) titer, and increases in interleukin 2 (IL-2), IL-6, and interferon γ (IFN-γ) mRNA levels were observed on days 21 and 42 (P < 0.05). Treatment with the higher AFB₁ doses (groups T2 and T3) reduced the chicks' growth performance on days 21 and 42, measured as reductions in body weight (BW) and average daily gain (ADG) compared with the control group. In the T2 and T3 groups, the total antioxidant capacity (T-AOC), glutathione peroxidase (GPX) and superoxide dismutase (SOD) activities, serum immunoglobulin A (IgA) and IgG levels, and IL-2, IL-6, and IFN-γ levels were also lower than in the control group. On days 21 and 42, these two groups also showed increased malondialdehyde (MDA) content, higher feed to gain ratio (F/G), and higher IL-2, IL-6, and IFN-γ mRNA levels than the control group (P < 0.05). The T2 and T3 groups also showed reduced T-AOC, NDV-Ab titer, IL-2 content, and GPx-1 mRNA levels on days 21 and 42 (P < 0.05), increased IL-6 and IFN-γ mRNA levels on day 21, and increased F/G and MDA content on day 42 (P < 0.05) compared with group (T1). Increased MDA content and IL-6 mRNA levels in the liver and ileum were observed in group T3 compared with group T2 on day 21, and lower IgM and IL-6 levels were observed on days 21 and 42 (P < 0.05). In conclusion, our data showed that AFB₁ exposure resulted in dose-dependent oxidative and inflammatory damage, immunosuppression, and a decline in the growth performance of chicks.

Fumonisin B1 Induces Immunotoxicity and Apoptosis of Chicken Splenic Lymphocytes

Fumonisin B₁ (FB₁), produced by Fusarium, is among the most abundant and toxic mycotoxin contaminations in feed, causing damages to the health of livestock. However, the mechanisms of FB₁ toxicity in chickens are less understood. As splenic lymphocytes play important roles in the immune system, the aim of this study was to investigate the immunotoxic effects and mechanisms of FB₁ on chicken splenic lymphocytes. In the present study, the chicken primary splenic lymphocytes were harvested and treated with 0, 2.5, 5, 10, 20 and 40 μg/mL FB₁. Then, the cell proliferation, damage, ultrastructure, inflammation and apoptosis were evaluated. Results showed that the proliferation rate of splenic lymphocytes was decreased by FB₁ treatments. The activity of lactate dehydrogenase (LDH) was increased by FB₁ treatments in a dose-dependent manner, implying the induction of cell damage. Consistently, the ultrastructure of splenic lymphocytes showed that FB₁ at all the tested concentrations caused cell structure alterations, including nuclear vacuolation, mitochondrial swelling and mitochondrial crest fracture. Besides, immunosuppressive effects of FB₁ were observed by the decreased concentrations of interleukin-2 (IL-2), IL-4, IL-12 and interferon-γ (IFN-γ) in the cell culture supernatant. Furthermore, apoptosis was observed in FB₁-treated cells by flow cytometry. The mRNA expressions of apoptosis-related genes showed that the expression of Bcl-2 was decreased, while the expressions of the P53, Bax, Bak-1, and Caspase-3 were increased with FB₁ treatment. Similar results were found in the concentrations of apoptosis-related proteins in the cell supernatant by ELISA assay. Moreover, regression analysis indicated that increasing FB₁ concentration increased LDH activity, concentrations of Bax, Bak-1 and mRNA expression of Bak-1 linearly, increased M1 area percentage quadratically, decreased concentration of IFN-γ, mRNA expression of Bcl-2 linearly, and decreased concentrations of IL-2 and IL-4 quadratically. Besides, regression analysis also showed reciprocal relationships between IL-12 concentration, Caspase-3 mRNA expression and increasing FB₁ concentration. The increasing FB₁ concentration could decrease IL-12 concentration and increase Caspase-3 mRNA expression. Altogether, this study reported that FB₁ induced the immunotoxicity of chicken splenic lymphocytes and caused splenic lymphocytes apoptosis by the Bcl-2 family-mediated mitochondrial pathway of caspase activation.

Mycotoxins’ Toxicological Mechanisms Involving Humans, Livestock and Their Associated Health Concerns: A Review

Mycotoxins are well established toxic metabolic entities produced when fungi invade agricultural/farm produce, and this happens especially when the conditions are favourable. Exposure to mycotoxins can directly take place via the consumption of infected foods and feeds; humans can also be indirectly exposed from consuming animals fed with infected feeds. Among the hundreds of mycotoxins known to humans, around a handful have drawn the most concern because of their occurrence in food and severe effects on human health. The increasing public health importance of mycotoxins across human and livestock environments mandates the continued review of the relevant literature, especially with regard to understanding their toxicological mechanisms. In particular, our analysis of recently conducted reviews showed that the toxicological mechanisms of mycotoxins deserve additional attention to help provide enhanced understanding regarding this subject matter. For this reason, this current work reviewed the mycotoxins’ toxicological mechanisms involving humans, livestock, and their associated health concerns. In particular, we have deepened our understanding about how the mycotoxins’ toxicological mechanisms impact on the human cellular genome. Along with the significance of mycotoxin toxicities and their toxicological mechanisms, there are associated health concerns arising from exposures to these toxins, including DNA damage, kidney damage, DNA/RNA mutations, growth impairment in children, gene modifications, and immune impairment. More needs to be done to enhance the understanding regards the mechanisms underscoring the environmental implications of mycotoxins, which can be actualized via risk assessment studies into the conditions/factors facilitating mycotoxins’ toxicities.

Alginate oligosaccharides protect against fumonisin B1-induced intestinal damage via promoting gut microbiota homeostasis

Fumonisin B1 (FB1), one of the most common mycotoxins contaminating feed and food, has been shown to induce intestinal barrier degradation. However, its role on gut microbiota in this process is still unclear. Alginate oligosaccharides (AOS) have been reported to exert their anti-inflammatory and anti-apoptotic function partially via modulation the gut microbiota. However, little is known about the beneficial effect of AOS on gut microbiota upon FB1 exposure. Results show that FB1 degraded intestinal epithelial barrier function as evidenced by increased pathological epithelial cell shedding, reduced the number of goblet cells, and promoted intestinal cell apoptosis. Markedly, FB1 disturbed the cecal and fecal microbiota composition. FB1 increased the level of Lactobacillus and decreased the relative abundance of beneficial microbes. FB1 largely inhibited the production of short chain fatty acids (SCFAs). AOS greatly ameliorated FB1-induced intestinal damage, inflammation, and oxidative stress (eg., T-SOD and MDA). AOS alleviated gut microbial dysbiosis by promoting the growth of beneficial microbes such as Roseburia, Bifidobacterium, and Akkermansia, and increasing SCFAs production upon FB1 exposure. Moreover, the correlation analysis showed that FB1- and AOS-treated gut microbiota alteration is closely associated with the change of intestinal phenotype. We have thus provided a novel insight into the protective role of AOS on FB1-induced gut microbial dysbiosis.

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).

Rabies Vaccination in Dogs in Laos: Owner Knowledge and Serological Status of Dogs

Rabies is an infectious disease which is virtually 100% fatal. Humans are most often infected through the bite of an infected dog, and most cases could be prevented by vaccinating dogs. However, vaccination coverage is insufficient in most countries where canine rabies occurs endemically. This study conducted interviews and sampling of dogs in Laos to understand more about the barriers for vaccination and to evaluate the antibody status of dogs using a commercial ELISA. The study found that only 62% out of 359 dog owners knew what rabies was, and only 24% knew the disease could be fatal. Higher education was associated with higher knowledge scores. Only 56 out of 437 (13%) dogs had been rabies vaccinated according to their owner, and out of these dogs, only 34 (61%) had antibodies, and only 48% had adequate levels (above 0.5 IU/mL). However, 24% of the dogs with no known history of vaccination had antibodies, indicating either exposure or vaccination in the past without the owner's awareness. In conclusion, this study indicates that there is a low level of knowledge about rabies, and that owner knowledge is not a good indicator of whether a dog is vaccinated or not.

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.

Effects of a Low Dose of T-2 Toxin on the Percentage of T and B Lymphocytes and Cytokine Secretion in the Porcine Ileal Wall

Plant materials used in the production of pig feed are frequently contaminated with mycotoxins. T-2 toxin is a secondary metabolite of selected Fusarium species, and it can exert a harmful influence on living organisms. Most mycotoxins enter the body via the gastrointestinal tract, and they can modulate the gut-associated lymphoid tissue (GALT) function. However, little is known about the influence of low T-2 toxin doses on GALT. Therefore, the aim of this study was to evaluate the effect of T-2 toxin administered at 50% of the lowest-observed-adverse-effect level (LOAEL) on the percentage of CD2+ T cells, CD4+ T helper cells, CD8+ cytotoxic T cells, CD4+CD8+ double-positive T cells, TCRγδ+ cells, CD5+CD8- B1 cells, and CD21+ B2 cells, and the secretion of proinflammatory (IFN-γ, IL-1β, IL-2, IL-12/23p40, IL-17A), anti-inflammatory, and regulatory (IL-4, IL-10, TGF-β) cytokines in the porcine ileal wall. The results of the study revealed that T-2 toxin disrupts the development of tolerance to food antigens by enhancing the secretion of proinflammatory and regulatory cytokines and decreasing the production of anti-inflammatory TGF-β. T-2 toxin triggered the cellular response, which was manifested by an increase in the percentage of CD8+ T cells and a decrease in the percentage of B2 and Tγδ lymphocytes.

Dietary Oxidative Distress: A Review of Nutritional Challenges as Models for Poultry, Swine and Fish

The redox system is essential for maintaining cellular homeostasis. When redox homeostasis is disrupted through an increase of reactive oxygen species or a decrease of antioxidants, oxidative distress occurs resulting in multiple tissue and systemic responses and damage. Poultry, swine and fish, raised in commercial conditions, are exposed to different stressors that can affect their productivity. Some dietary stressors can generate oxidative distress and alter the health status and subsequent productive performance of commercial farm animals. For several years, researchers used different dietary stressors to describe the multiple and detrimental effects of oxidative distress in animals. Some of these dietary challenge models, including oxidized fats and oils, exposure to excess heavy metals, soybean meal, protein or amino acids, and feeding diets contaminated with mycotoxins are discussed in this review. A better understanding of the oxidative distress mechanisms associated with dietary stressors allows for improved understanding and evaluation of feed additives as mitigators of oxidative distress.

Molecular and epigenetic modes of Fumonisin B1 mediated toxicity and carcinogenesis and detoxification strategies

Fumonisin B₁ (FB₁) is a natural contaminant of agricultural commodities that has displayed a myriad of toxicities in animals. Moreover, it is known to be a hepatorenal carcinogen in rodents and may be associated with oesophageal and hepatocellular carcinomas in humans. The most well elucidated mode of FB₁-mediated toxicity is its disruption of sphingolipid metabolism; however, enhanced oxidative stress, endoplasmic reticulum stress, autophagy, and alterations in immune response may also play a role in its toxicity and carcinogenicity. Alterations to the host epigenome may impact on the toxic and carcinogenic response to FB₁. Seeing that the contamination of FB₁ in food poses a considerable risk to human and animal health, a great deal of research has focused on new methods to prevent and attenuate FB₁-induced toxic consequences. The focus of the present review is on the molecular and epigenetic interactions of FB₁ as well as recent research involving FB₁ detoxification.

Fumonisins B1 exposure triggers intestinal tract injury via activating nuclear xenobiotic receptors and attracting inflammation response

Fumonisins (FBs) are mycotoxins that are widely distributed in crops and feed, and ingestion of FBs -contaminated crops is harmful to animal health. Furthermore, it is unknown if Fumonisins B1 (FB1) can cause intestinal toxicity. To investigate FB1-induced intestinal toxicity, mice were treated with 0 or 5 mg/kg FB1 by gavage administration for 42 days. Histopathology indicated that FB1 exposure caused proliferation of intestinal epithelial cells, intestinal villi and epithelial layer shedding, intestinal gland atrophy, and necrosis. Notably, FB1 interfered with nuclear xenobiotic receptors (NXR) homeostasis by regulating the level of aryl hydrocarbon receptor (AHR), constitutive androstane receptor (CAR), pregnane X receptor (PXR) and downstream target genes (CYP450s). Moreover, abnormal expression of inflammatory cytokines (IL-1β, IL-2, IL-4, IL-10, and TNF-α) indicated the occurrence of inflammation. The present study provides new insights regarding the mechanism of FB1-induced intestinal toxicity through activating the NXR system and by triggering inflammatory responses in the intestinal tract in mice.

Effects of mycotoxin-contaminated feed on farm animals

Mycotoxins are secondary products produced by fungi in cereals and are frequently found in the livestock industry as contaminants of farm animal feed. Studies analyzing feed mycotoxins have been conducted worldwide and have confirmed the presence of mycotoxins with biological activity, including aflatoxin, ochratoxin A, fumonisin, zearalenone, and deoxynivalenol, in a large proportion of feed samples. Exposure to mycotoxins can cause immunotoxicity and impair reproductive function in farm animals. In addition, exposure of tissues, such as the kidneys, liver, and intestines, to mycotoxins can exert histopathological changes that can interfere with animal growth and survival. This review describes previous studies regarding the presence of major mycotoxins in the feed of farm animals, especially pigs and poultry. Moreover, it describes the adverse effects of mycotoxins in farm animals following exposure, as well as the biological activity of mycotoxins in animal-derived cells. Mycotoxins have been shown to regulate signaling pathways, oxidative stress, endoplasmic reticulum stress, apoptosis, and proliferation in porcine and bovine cells. A clear understanding of the effects of mycotoxins on farm animals will help reduce farm household economic loss and address the health concerns of people who consume these meat and dairy products.

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.

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.

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.

Application of biomarker methods to investigate FUMzyme mediated gastrointestinal hydrolysis of fumonisins in pigs

Fumonisins are among the most prevalent mycotoxins in feedstuffs. They disrupt the sphingolipid metabolism, thereby inducing a plethora of toxic effects in livestock. Supplementation with mycotoxin-degrading enzymes is a promising strategy for the detoxification of feedstuffs in the animals’ gastrointestinal tract. Here, we evaluated the suitability of the fumonisin esterase FumD as a feed additive (FUMzyme®) for the prevention of fumonisin toxicity in pigs by using a combination of different fumonisin biomarkers (sphinganine to sphingosine (Sa/So) ratio in serum and organs, concentrations of fumonisin B1 and hydrolysed derivatives in urine and faeces). In a pre-trial, we exposed pigs to 30 mg/kg fumonisins in feed and found the minimum effective dose of FUMzyme to be 15 U/kg. In a second trial we investigated the long-term efficacy of this minimum effective FUMzyme dose to counteract toxic effects elicited by 6 weeks of exposure to 2.5 mg/kg fumonisins in a diet containing naturally contaminated maize. Supplementation of feed with the minimum effective FUMzyme dose prevented an increase in the Sa/So ratio in serum and kidneys of fumonisin exposed pigs. The Sa/So ratio in serum proved to be the most reliable biomarker. The fumonisin pattern in faeces was less suitable as biomarker for assessing the efficacy of FUMzyme due to natural gastrointestinal hydrolysis of fumonisins. Analysis of urine samples provided additional information about gastrointestinal fumonisin hydrolysis before fumonisin absorption, but was analytically challenging because of low urinary fumonisin concentrations.

Oral and Intravenous Fumonisin Exposure in Pigs-A Single-Dose Treatment Experiment Evaluating Toxicokinetics and Detoxification

We examined the toxicokinetics of fumonisin B₁ (FB1) and its main metabolites after single dose application intravenously (iv) of 139 nmol FB1 or hydrolyzed FB1 (HFB1)/kg bodyweight (BW) in barrows (BW: 34.4 kg ± 2.7 kg), as well as the toxicokinetics of FB1, FB2, FB3 and FB1 bioavailability from oral exposure (3425 nmol FB1/kg BW, on top of ration). Additionally, detoxification efficacy of FumD (240 U/kg feed; 3321 nmol FB1/kg BW), a fumonisin esterase, was examined for oral fumonisin application. Urine and feces were collected quantitatively and serum samples were taken over a period of 120 h. Serum toxicokinetics of FB1iv showed a short distribution half-life of 6 min followed by a longer elimination half-life of 36 min. After HFB1iv administration, serum clearance was three times higher compared to FB1iv group (5.6 and 1.8 L/kg/h respectively) which together with a 5-times higher volume of distribution indicates that HFB1 is more rapidly cleared from systemic circulation but distributed more extensively into the extravasal space than FB1. The bioavailability of FB1 in orally exposed pigs was 5.2% (incl. metabolites). Moreover, we found a significant reduction of FB1 bioavailability by 90% caused by the action of fumonisin esterase in the gastrointestinal tract, clearly demonstrating the efficacy of FumD.

The molecular mechanism of cell cycle arrest in the Bursa of Fabricius in chick exposed to Aflatoxin B 1

Aflatoxin B₁ shows potent hepatotoxic, carcinogenic, genotoxic, immunotoxic potential in humans and many species of animals. The aim of this study was to clarify the underlying mechanism of G₀G₁ phase and G₂M phase arrest of cell cycle in the bursa of Fabricius in broilers exposed to dietary AFB₁. 144 one-day-old healthy Cobb broilers were randomly divided into two groups and fed on control diet and 0.6 mg·Kg⁻¹ AFB₁ diet for 3 weeks. Histological observation showed that AFB₁ induced the increase of nuclear debris and vacuoles in lymphoid follicle of BF. Results of flow cytometry studies showed that bursal cells arrested in G₂M phase at 7 days of age and blocked in G₀G₁ phase at 14 and 21 days of age following exposure to AFB₁. The qRT-PCR analysis indicated that cell cycle arrested in G₂M phase via ATM-Chk2-cdc25-cyclin B/cdc2 pathway, and blocked in G₀G₁ phase through ATM-Chk2-cdc25-cyclin D/CDK6 pathway and ATM-Chk2-p21-cyclin D/CDK6 route. In a word, our results provided new insights that AFB₁ diet induced G₂M and G₀G₁ phase blockage of BF cells in different periods, and different pathways were activated in different arrested cell cycle phase.

Identification of Signaling Pathways Targeted by the Food Contaminant FB1: Transcriptome and Kinome Analysis of Samples from Pig Liver and Intestine

SCOPE

Fumonisin B1 (FB1) is a mycotoxin produced by Fusarium species. In mammals, this toxin causes widespread organ-specific damage; it promotes hepatotoxicity, is immunotoxic, alters intestinal functions etc. Despite its inhibitory effect on de novo ceramide synthesis, its molecular mechanism of action and toxicity is not totally elucidated.

METHODS AND RESULTS

To explore the mechanism of FB1 toxicity, we analyzed the transcriptome and the kinome of two organs targeted by FB1: the liver and the jejunum. Pigs were fed for 4 weeks a control diet or a FB1-contaminated diet (10 mg/kg). As expected, FB1-exposed pigs gained less weight and displayed a higher sphinganine/sphingosine ratio. Comparison of the transcriptomes and the kinomes of treated versus control pigs showed striking differences. Among the disrupted pathways in liver and jejunum, we highlight Protein Kinase B (AKT) / Phosphatase and tensin homolog (PTEN) at the intersection of the FB1-modulated pathways.

CONCLUSION

Most of the effects of FB1 are mediated by the regulation of ceramide level, which influences protein phosphatase 2 (PP2A) and the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway. This pathway might be a new target to counteract toxic effect of Fumonisin B1, which is one of the most spread food contaminant in the world.

Evaluation of the cytotoxic properties, gene expression profiles and secondary signalling responses of cultured cells exposed to fumonisin B1, deoxynivalenol and zearalenone mycotoxins

Mycotoxins are toxic secondary metabolites produced by a range of fungi and are common contaminants of agricultural crops. These toxins are chemically diverse and structurally stable, enabling them to enter the food chain which can lead to numerous adverse health effects in animals and humans. Although mycotoxin exposure is associated with the development of several cancers, it has proved challenging to show a direct connection between exposure and oncogenic change. This study investigates the in vitro cytotoxicity, molecular mechanisms and secondary signalling responses associated with the exposure to three major mycotoxins, fumonisin B1 (FB1), deoxynivalenol (Don) and zearalenone (Zea). The cytotoxicity of FB1, Don and Zea were investigated in cultured HepG2 and Caco-2 cells using cell viability assays as well as flow cytometry. FB1 proved to be less cytotoxic than its counterparts, while Don and Zea demonstrated high cytotoxicity through an apoptotic mechanism. Expression profiles of 84 genes involved in mediating communication between tumour cells and the cellular mediators of inflammation as well as the innate immune system were also studied. The expression profiles associated with the different mycotoxins were further explored for functional networks, biological functions, canonical pathways, toxicological association as well as to predict network associations between the differentially expressed genes. RT-qPCR revealed the significant differential expression of 46 genes, including the expression of several genes strongly associated with cancer and aberrant inflammatory signalling, after mycotoxin exposure. Aberrant inflammatory signalling seems to be a credible contributing factor that initiates the malignant change observed in cells exposed to mycotoxins.

Feed exposure to FB1 can aggravate pneumonic damages in pigs provoked by P. multocida

The possible interaction between Pasteurella multocida and the mycotoxin fumonisin B1 (FB1), recognised as one of the most often food/feed contaminant, was studied with the aim to evaluate whether and how FB1 can influence and/or complicate the development and severity of various pathological damages provoked by Pasteurella multocida in some internal organs of pigs. Heavier lung pathology was seen in pigs experimentally infected with Pasteurella multocida, when the same were exposed to 20ppm dietary levels of fumonisin B1 (FB1) as was assessed by gross pathology, pathomorphological examinations, clinical biochemistry and some immunological investigations. The most typical damages in FB1 treated pigs were the strong oedema in the lung and the slight oedema in the other internal organs and mild degenerative changes in the kidneys, whereas the typical pathomorphological findings in pigs infected with Pasteurella multocida was broncho-interstitial pneumonia. FB1 was found to aggravate pneumonic changes provoked by P. multocida in the cranial lobes of the lung and to complicate pneumonic damages with interstitial oedema in the lung. No macroscopic damages were observed in the pigs infected only with Pasteurella multocida. It can be concluded that the feed intake of FB1 in pigs may complicate or exacerbate the course of P. multocida serotype A infection.

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.

Foodborne mycotoxicoses, risk assessment and underestimated hazard of masked mycotoxins and joint mycotoxin effects or interaction

The existing hazard of joint mycotoxin exposure of animals/humans and the significance of masked mycotoxins in foods or feeds and their respective contributions to the development of some food born mycotoxicoses is briefly reviewed. The importance of joint mycotoxin interaction in the complex etiology of some foodborn mycotoxicoses is covered in depth. The toxicity of low contamination levels of some combinations of mycotoxins ingested often by farm animals was carefully studied. The appropriate hygiene control and the necessary risk assessment in regard to mycotoxin contamination of foods and feeds are briefly analyzed and some useful prophylactic measures and management of the risk of mycotoxin contamination, in addition to tolerable daily intakes are also described. A reference is also made to the most suitable methods of veterinary hygiene control in some practical situations in order to prevent mycotoxins contaminating commercial food commodities and endangering public health.

Induction of pro-inflammatory gene expression by Escherichia coli and mycotoxin zearalenone contamination and protection by a Lactobacillus mixture in porcine IPEC-1 cells

This work investigated the effect of Escherichia coli K88 and zearalenone contamination on pro-inflammatory gene expression (Toll like receptors, cytokines) and signalling molecules and the protective activity of a mixture of Lactobacilli sp. (Lactobacillus plantarum, Lactobacillus acidofilus and Lactobacillus paracasei) in porcine intestinal epithelial cells as part of the local immune system. IPEC-1 cell monolayer was exposed for 1 h to the individual or combined action of E. coli, zearalenone and lactobacilli mixture. Our results showed that TLRs (1-10) and cytokine (IL-1,-6,-8,-10, TNF-α, IFN-γ) genes expressed early (after 1 h of culture) in IPEC-1 cells. E. coli alone increased the TLRs mRNA expression, especially TLR4 and the inflammatory cytokines while ZEA alone showed either no effect or a marginally effect on TLRs, cytokines, and signalling genes when compared to untreated cells. The combined actions of the two contaminants lead to a synergistically up-regulation of key cytokines (IFN-γ, IL-10 and TNF-α) and TLRs (-2,-3,-4,-6, and -10). The live lactobacilli mixture was able to attenuate the pathogen and mycotoxin-induced response by downregulated the majority of inflammatory related genes suggesting that this mixture has an immunomodulatory potential and may be used to lower the inflammatory response.

A comparative pathological finding in pigs exposed to fumonisin B1 and/or Mycoplasma hyopneumoniae

A more complicated pathology was observed in female pigs infected with Mycoplasma hyopneumoniae, when the same were exposed to 20 ppm dietary levels of fumonisin B1 (FB1) starting 14 days before infection for a period of 42 days as was assessed by gross pathology and pathomorphological examinations or computed tomography, and also manifested by the strong deterioration of the pneumonic process in two pigs and the subsequent euthanizing of one pig. Typical damages in FB1-fed pigs were a strong oedema in the lung and slight oedema in the other internal organs and mild degenerative changes in the kidneys, whereas the typical pathomorphological changes in M. hyopneumoniae-infected pigs corresponded to the morphologic pattern of a catarrhal bronchointerstitial pneumonia more pronounced in the cranial and middle lobes or in the cranial third of the caudal lobe of the lung. The pigs treated by both pathogens (toxic and infectious) revealed strong oedematous changes in the interstitium of lung in addition to deteriorated and extended bronchointerstitial pneumonic process.

The peripheral blood transcriptome reflects variations in immunity traits in swine: towards the identification of biomarkers

BACKGROUND

Immune traits (ITs) are potentially relevant criteria to characterize an individual's immune response. Our aim was to investigate whether the peripheral blood transcriptome can provide a significant and comprehensive view of IT variations in pig.

RESULTS

Sixty-day-old Large White pigs classified as extreme for in vitro production of IL2, IL10, IFNγ and TNFα, phagocytosis activity, in vivo CD4⁻/CD8⁺ or TCRγδ + cell counts, and anti-Mycoplasma antibody levels were chosen to perform a blood transcriptome analysis with a porcine generic array enriched with immunity-related genes. Differentially expressed (DE) genes for in vitro production of IL2 and IL10, phagocytosis activity and CD4⁻/CD8⁺ cell counts were identified. Gene set enrichment analysis revealed a significant over-representation of immune response functions. To validate the microarray-based results, a subset of DE genes was confirmed by RT-qPCR. An independent set of 74 animals was used to validate the covariation between gene expression levels and ITs. Five potential gene biomarkers were found for prediction of IL2 (RALGDS), phagocytosis (ALOX12) or CD4⁻/CD8⁺ cell count (GNLY, KLRG1 and CX3CR1). On average, these biomarkers performed with a sensitivity of 79% and a specificity of 86%.

CONCLUSIONS

Our results confirmed that gene expression profiling in blood represents a relevant molecular phenotype to refine ITs in pig and to identify potential biomarkers that can provide new insights into immune response analysis.

Biotransformation approaches to alleviate the effects induced by fusarium mycotoxins in swine

Mycotoxin mitigation is of major interest as ingestion of mycotoxins results in poor animal health, decreased productivity, as well as substantial economic losses. A feed additive (FA) consisting of a combination of bacteria (Eubacterium BBSH797) and enzyme (fumonisin esterase FumD) was tested in pigs for its ability to neutralize the effects of mono- and co-contaminated diets with deoxynivalenol (DON) and fumonisins (FB) on hematology, biochemistry, tissue morphology, and immune response. Forty-eight animals, allocated into eight groups, received one of eight diets for 35 days: a control diet, a diet contaminated with either DON (3 mg/kg) or FB (6 mg/kg), or both toxins, and the same four diets with FA. Inclusion of FA restored the circulating number of neutrophils of piglets fed the FB and DON + FB diets. Similarly, FA counteracted the minor changes observed on plasma concentrations of albumin and creatinine. In lung, the lesions induced by the ingestion of FB in mono- and co-contaminated diets were no longer observed after addition of FA in these diets. Lesions recorded in the liver of pigs fed either of the contaminated diets with FA were partly reduced, and the increased hepatocyte proliferation was totally neutralized when FA was present in the co-contaminated diet. After 35 days of exposure, the development of the vaccinal response was significantly improved in animals fed diets supplemented with FA, as shown by results of lymphocyte proliferation, cytokine expression in spleen, and the production of specific Ig. Similarly, in jejunum of animals fed diets with FA, occurrence of lesions and upregulation of pro-inflammatory cytokines were much less obvious. The ameliorative effects provided by FA suggest that this approach would be suitable in the control of DON and FB that commonly co-occur in feed.

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

The objective of this study was to measure the effects of chronic exposure to fumonisins via the ingestion of feed containing naturally contaminated corn in growing pigs infected or not with Salmonella spp. This exposure to a moderate dietary concentration of fumonisins (11.8 ppm) was sufficient to induce a biological effect in pigs (Sa/So ratio), but no mortality or pathology was observed over 63 days of exposure. No mortality or related clinical signs, even in cases of inoculation with Salmonella (5 × 10⁴ CFU), were observed either. Fumonisins, at these concentrations, did not affect the ability of lymphocytes to proliferate in the presence of mitogens, but after seven days post-inoculation they led to inhibition of the ability of specific Salmonella lymphocytes to proliferate following exposure to a specific Salmonella antigen. However, the ingestion of fumonisins had no impact on Salmonella translocation or seroconversion in inoculated pigs. The inoculation of Salmonella did not affect faecal microbiota profiles, but exposure to moderate concentrations of fumonisins transiently affected the digestive microbiota balance. In cases of co-infection with fumonisins and Salmonella, the microbiota profiles were rapidly and clearly modified as early as 48 h post-Salmonella inoculation. Therefore under these experimental conditions, exposure to an average concentration of fumonisins in naturally contaminated feed had no effect on pig health but did affect the digestive microbiota balance, with Salmonella exposure amplifying this phenomenon.

Aflatoxin B1 modulates the expression of phenotypic markers and cytokines by splenic lymphocytes of male F344 rats

Aflatoxin B1 (AFB1) is immunotoxic to animals and a suspected immunosuppressant in humans. In this study, we investigated the effects of AFB1 on splenic lymphocyte phenotypes and the inflammatory cytokine expression in male F344 rats. Exposure of animals to AFB1 [5-75 µg kg(-1) body weight (BW)] for 1 week showed dose-dependent decreases in the percentage of splenic CD8(+) T cells and CD3(-) CD8a(+) NK cells. A general inhibition of the expression of interleukin (IL)-4 and interferon (IFN)-γ by CD4(+) T cells, IL-4 and IFN-γ by CD8a(+) cells, and tumor necrosis factor (TNF)-α expression by natural killer (NK) cells was also found; however, no concurrent histological changes in spleen tissue were present, suggesting acute immunosuppression without overt toxicity. Five-week exposure with AFB1 significantly increased the percentages of CD3(+) and CD8(+) T cells, especially at low doses (≤ 25 µg kg(-1)). AFB1 treatment significantly decreased the anti-inflammatory cytokine IL-4 expression by CD4(+) T cells and significantly increased the pro-inflammatory cytokine IFN-γ expression by CD4(+) T cells and TNF-α expression by NK cells. These results indicated that repeated AFB1 exposure promotes inflammatory responses by regulating cytokine expression. Our data provides novel insights into the mechanisms by which AFB1 exposure differentially modulates the cell-mediated immune responses and suggests the involvement of an inflammatory response upon repeated exposure.

Use of computed tomography and histopathologic review for lung lesions produced by the interaction between Mycoplasma hyopneumoniae and fumonisin mycotoxins in pigs

Mycoplasma hyopneumoniae has a primary role in the porcine respiratory disease complex (PRDC). The objective of this study was to determine whether fumonisin mycotoxins influence the character and/or the severity of pathological processes induced in the lungs of pigs by Mycoplasma hyopneumoniae. Four groups of pigs (n = 7/group) were used, one fed 20 ppm fumonisin B1 (FB1) from 16 days of age (group F), one only infected with M. hyopneumoniae on study day 30 (group M), and a group fed FB1 and infected with M. hyopneumoniae (group MF), along with an untreated control group (group C). Computed tomography (CT) scans of infected pigs (M and MF) on study day 44 demonstrated lesions extending to the cranial and middle or in the cranial third of the caudal lobe of the lungs. The CT images obtained on study day 58 showed similar but milder lesions in 5 animals from group M, whereas lungs from 2 pigs in group MF appeared progressively worse. The evolution of average pulmonary density calculated from combined pixel frequency values, as measured by quantitative CT, was significantly influenced by the treatment and the age of the animals. The most characteristic histopathologic lesion in FB1-treated pigs was pulmonary edema, whereas the pathomorphological changes in Mycoplasma-infected pigs were consistent with catarrhal bronchointerstitial pneumonia. FB1 aggravated the progression of infection, as demonstrated by severe illness requiring euthanasia observed in 1 pig and evidence of progressive pathology in 2 pigs (group MF) between study days 44 and 58.

Effects of oral deoxynivalenol exposure on immune-related parameters in lymphoid organs and serum of mice vaccinated with porcine parvovirus vaccine

Mice were exposed to deoxynivalenol (DON) via drinking water at a concentration of 2 mg/L for 36 days. On day 8 of treatment, inactivated porcine parvovirus vaccine (PPV) was injected intraperitoneally. The relative and absolute weight of the spleen was significantly decreased in the DON-treated group (DON). Antibody titers to parvovirus in serum were 47.9 ± 2.4 in the vaccination group (Vac), but 15.2 ± 6.5 in the group treated with DON and vaccine (DON + Vac). The IgA and IgG was not different in the DON, Vac an,d DON + Vac groups. IgM was significantly lower only in the DON + Vac group. However IgE was significantly increased in the Vac and DON + Vac group, but no change was observed between the Vac and DON + Vac groups. The concentrations of IL-2, IL-4, GM-CSF, MCP-1 and Rantes in serum, and IL-1α in mesenteric lymph node and MIP-1β in spleen were significantly increased by DON treatment compared to control. The concentrations of IL-2, IL-5, IL-6, IL-9, IL-12, IL-13 and Rantes in thymus, of IL-2 in spleen, and of IL-1α, IL-1β, IL-3, IL-5, IL-10, IL-17, G-CSF, GM-CSF and MCP-1 in mesenteric lymph nodes were significantly decreased in mice compared to those in the Vac group, while concentrations of IL-1α, IL-2, IL-9, IL-13,G-CSF, GM-CSF, IFN-γ, MCP-1, MIP-1α and TNF-α were significantly increased in serum compared to the Vac group. In conclusion, the results presented here indicate that exposure to DON at 2.0 mg/L via drinking water can disrupt the immune response in vaccinated mice by modulating cytokines and chemokines involved in their immune response to infectious disease.

Chronic ingestion of deoxynivalenol and fumonisin, alone or in interaction, induces morphological and immunological changes in the intestine of piglets

Deoxynivalenol (DON) and fumonisins (FB) are mycotoxins produced by Fusarium species, which naturally co-occur in animal diets. The gastrointestinal tract represents the first barrier met by exogenous food/feed compounds. The purpose of the present study was to investigate the effects of DON and FB, alone and in combination, on some intestinal parameters, including morphology, histology, expression of cytokines and junction proteins. A total of twenty-four 5-week-old piglets were randomly assigned to four different groups, receiving separate diets for 5 weeks: a control diet; a diet contaminated with either DON (3 mg/kg) or FB (6 mg/kg); or both toxins. Chronic ingestion of these contaminated diets induced morphological and histological changes, as shown by the atrophy and fusion of villi, the decreased villi height and cell proliferation in the jejunum, and by the reduced number of goblet cells and lymphocytes. At the end of the experiment, the expression levels of several cytokines were measured by RT-PCR and some of them (TNF-α, IL-1β, IFN-γ, IL-6 and IL-10) were significantly up-regulated in the ileum or the jejunum. In addition, the ingestion of contaminated diets reduced the expression of the adherent junction protein E-cadherin and the tight junction protein occludin in the intestine. When animals were fed with a co-contaminated diet (DON+FB), several types of interactions were observed depending on the parameters and segments assessed: synergistic (immune cells); additive (cytokines and junction protein expression); less than additive (histological lesions and cytokine expression); antagonistic (immune cells and cytokine expression). Taken together, the present data provide strong evidence that chronic ingestion of low doses of mycotoxins alters the intestine, and thus may predispose animals to infections by enteric pathogens.

Deciphering the genetic control of innate and adaptive immune responses in pig: a combined genetic and genomic study

Improving animal robustness and resistance to pathogens by adding health criteria in selection schemes is one of the challenging objectives of the next decade. In order to better understand the genetic control of immunity in French Large White pigs, we have launched a program combining genetic and genomic studies not focussing on any particular pathogen. Animals recorded for production traits were scored for a wide range of immunity parameters three weeks after vaccination against Mycoplasma hyopneumoniae: i) total white blood cells and lymphocyte counts and proportions of various leucocyte subsets including cells harbouring IgM, γδTCR, CD4/CD8, CD16/CD2 and CD16/CD172a/MHCII, ii) innate immune response parameters (phagocytosis and in vitro production of IL1B, IL6, IL8, TNF, IL12 and IFNαafter blood stimulation), iii) adaptive immune response parameters (lymphocyte proliferation, in vitro production of IL2, IL4, IL10 and IFNγ after blood stimulation, total IgG, IgA, IgM and specific IgG levels) and iv) two acute phase proteins (C-reactive protein and haploglobin). Across traits, heritability estimates reached 0.4 on average (se=0.1) and 42 of the 54 measured parameters showed moderate to high heritabilities (≥0.2), confirming that many parameters are under genetic control and could be included in selection protocols. Functional analyses revealed that the blood transcriptome is informative for part of the immunity traits and should provide relevant phenotypic information to better characterize some immunity traits.

Enzyme characteristics of aminotransferase FumI of Sphingopyxis sp. MTA144 for deamination of hydrolyzed fumonisin B₁

Fumonisins are carcinogenic mycotoxins that are frequently found as natural contaminants in maize from warm climate regions around the world. The aminotransferase FumI is encoded as part of a gene cluster of Sphingopyxis sp. MTA144, which enables this bacterial strain to degrade fumonisin B(1) and related fumonisins. FumI catalyzes the deamination of the first intermediate of the catabolic pathway, hydrolyzed fumonisin B(1). We used a preparation of purified, His-tagged FumI, produced recombinantly in Escherichia coli in soluble form, for enzyme characterization. The structure of the reaction product was studied by NMR and identified as 2-keto hydrolyzed fumonisin B(1). Pyruvate was found to be the preferred co-substrate and amino group receptor (K (M) = 490 μM at 10 μM hydrolyzed fumonisin B(1)) of FumI, but other α-keto acids were also accepted as co-substrates. Addition of the co-enzyme pyridoxal phosphate to the enzyme preparation enhanced activity, and saturation was already reached at the lowest tested concentration of 10 μM. The enzyme showed activity in the range of pH 6 to 10 with an optimum at pH 8.5, and in the range of 6°C to 50°C with an optimum at 35°C. The aminotransferase worked best at low salt concentration. FumI activity could be recovered after preincubation at pH 4.0 or higher, but not lower. The aminotransferase was denatured after preincubation at 60°C for 1 h, and the residual activity was also reduced after preincubation at lower temperatures. At optimum conditions, the kinetic parameters K (M) = 1.1 μM and k (cat) = 104/min were determined with 5 mM pyruvate as co-substrate. Based on the enzyme characteristics, a technological application of FumI, in combination with the fumonisin carboxylesterase FumD for hydrolysis of fumonisins, for deamination and detoxification of hydrolyzed fumonisins seems possible, if the enzyme properties are considered.

Interaction between mycotoxins and causative agents of swine infective diseases

Mycotoxins are secondary metabolites of fungi that can contaminate animal feeds at all stages of food production chain. Consumption of feed contaminated with mycotoxins may result in immunosuppression, which represents a predisposing factor for occurence of infectious diseases in livestock. The influence on immune system is of special interest in swine industry. The technology on swine farms demands frequent vaccinations, which may be a problem in the case of immunocompromised animals. The aim of this paper was evaluation of mycotoxin influence on swine farms, as secondary factors for destabilization of animals? immunological system. Material for this research included the samples from five swine farms, where health disorders, i.e. clinical and patomorphological signs resembling the problem with infectious diseases in different swine categories, were detected. The applied research methods included: epidemiological and clinical evaluation, pathomorphological examination, laboratory testing of bacteriological and virusological tissue originating from dead animals, and microbiological feed testing in order to examine the presence of fungi and mycotoxins. The obtained results indicated the existence of positive interaction between mycotoxins and causative agents of swine infective diseases. Despite continual pharmaco- and immunoprophylaxis in swine, the health problems of bacterial ethiology (colibacilosis, enteroxemia, dysentery, pneumonia, endometritis) were detected. From an epidemiological point of view, the presence of mycotoxins in animal feed may induce a breakdown of active immunity and occurrence of disease even in properly vaccinated animals.