Effects of Fusarium moniliforme culture material containing known levels of fumonisin B1 on progress of Salmonella Gallinarum infection in Japanese quail: clinical signs and hematologic studies

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.

Effect of dietary supplementation of mannanoligosaccharides on hepatic gene expressions and humoral and cellular immune responses in aflatoxin-contaminated broiler chicks

The present study was conducted to investigate the effects of dietary supplementation of mannanoligosaccharides (MOS) on expression of hepatic immunological genes and immune responses in aflatoxin-contaminated broiler chicks. A total of 336 seven-day-old Ross broiler chicks were randomly allotted to 7 experimental treatments with 4 replicates and 12 birds per replicate. Experimental treatments consisted of 2 aflatoxin levels (0.5 and 2 ppm) and 3 supplemental MOS levels (0, 1 and 2 g/kg) as a 2 × 3 factorial arrangement in comparison with a control group (unchallenged group). The chicks were challenged with a mix of aflatoxins during 7-28 d of age. Results showed that aflatoxin challenge resulted in the lower antibody titers against infectious bronchitis (IBV) and bursal (IBD) diseases viruses. In addition, aflatoxin-contaminated birds had a lower (P < 0.0001) lymphocyte percentage and a decline in (P < 0.01) interleukin-2 (IL-2) mRNA abundance. Likewise, heterophil proportion, heterophil to lymphocyte ratio and gene expressions of hepatic interleukin-6 (IL-6) and C reactive protein (CRP) were raised (P < 0.001) by increasing dietary aflatoxin level. Dietary inclusion of MOS increased (P < 0.05) antibody titers against IBV, IBD and Newcastle disease virus. Lymphocyte proportion and hepatic IL-2 gene expression were greater (P < 0.0001) in MOS-supplemented birds. Furthermore, supplemental MOS decreased hepatic IL-6 and CRP abundances. Additionally, inclusion of 2 g/kg MOS resulted in the upregulation (P < 0.01) of hepatic IL-2 gene expression in birds contaminated with 0.5 ppm aflatoxin. The present results indicate that supplemental MOS could improve cellular immunity via the upregulation of hepatic IL-2 gene expression in birds challenged with aflatoxins.

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.

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.

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.

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.

Individual and combined effects of fumonisin b1 and moniliformin on clinicopathological and cell-mediated immune response in Japanese quail

A total of 390 one-day-old quail chicks (Coturnix coturnix japonica) were divided into 4 groups (3 replicates per treatment), viz. CX, FX, MX, and FM, containing 75, 105, 105, and 105 birds, respectively. Birds in the control group (CX) were fed quail mash alone, whereas birds in group FX were fed 200 ppm of fumonisin B(1) (FB(1)) from Fusarium verticillioides culture material; group MX was fed 100 ppm of moniliformin (M) from Fusarium fujikuroi culture material; and group FM was fed a combination of 200 ppm of FB(1) and 100 ppm of M. Diets were fed from d 1 to 35 to study clinical signs, growth response, serum biochemical changes, and cell-mediated immune response. Birds fed FB(1) (FX) showed ruffled feathers and poor growth. Birds in group MX appeared more stunted than those in group FX and exhibited signs of poor feathering and decreased feed and water intake. Clinical signs observed in group FM were more or less similar to those observed in groups FX and MX. Total mortality was 12.38, 7.62, and 20.95% for groups FX, MX, and FM, respectively. Mean BW in groups FX, MX, and FM were significantly lower than those in the control group (CX) at almost all intervals. Total serum proteins, albumin, cholesterol, aspartate transaminase, lactate dehydrogenase, and creatine kinase values were higher in all treatment groups compared with the control group. Cell-mediated immune response was more or less comparable in groups CX and MX, whereas the presence of FB(1) in the diet of groups FX and FM was found to be associated with a gradual increase in skin thickness, and the mononuclear inflammatory cell response was poor as compared with groups CX and MX throughout the study. Except for mortality (additive effect) and serum aspartate transaminase values (less than an additive effect up to 14 DPF), no additive or synergistic effects were observed for any of the other response variables measured in the current study, where all statistical differences were attributed to either one mycotoxin or the other.

Impact of feed-borne mycotoxins on avian cell-mediated and humoral immune responses

Mycotoxins of economic importance in poultry production are mainly produced by Aspergillus, Penicillium and Fusarium fungi. The important mycotoxins in poultry production are aflatoxins, ochratoxins, trichothecenes, zearalenone and fumonisins. Mycotoxins exert their immunotoxic effects through various mechanisms which are manifested as reduced response of the immune system. Mycotoxin-induced immunosuppression in poultry may be manifested as decreased antibody production to antigens (e.g. sheep red blood cells) and impaired delayed hypersensitivity response (e.g. dinitrochlorobenzene), reduction in systemic bacterial clearance (e.g. Salmonella, Brucella, Listeria and Escherichia), lymphocyte proliferation (response to mitogens), macrophage phagocytotic ability, and alterations in CD4+/CD8+ ratio, immune organ weights (spleen, thymus and bursa of Fabricius), and histological changes (lymphocyte depletion, degeneration and necrosis). Mycotoxins, especially fumonisin B1 have been shown to down regulate proinflammatory cytokine levels including those of interferon (IFN)-γ, IFN-α, interleukin (IL)-1β, and IL-2 in broiler chickens. Fusarium mycotoxins exert part of their toxic effects by altering cytokine production in poultry. Mycotoxins adversely affect intestinal barrier functions by reducing the intestinal epithelial integrity and removing tight junction proteins. Apoptosis, increased colonisation of pathogenic microorganisms, cytotoxicity and oxidative stress, inhibition of protein synthesis and lipid peroxidation are characteristic of the toxic effects of mycotoxins on intestinal epithelium. These directly or indirectly affect host immune responses. Such immunotoxic effects of mycotoxins render poultry susceptible to many infectious diseases. The avian immune system is sensitive to most mycotoxins. Both cell-mediated and humoral immunity may be adversely affected after feeding mycotoxins to poultry. The avian immune system may be more sensitive to naturally contaminated feedstuffs because of the presence of multiple mycotoxins and the complex interactions between them which can cause severe adverse effects. Adverse effects of mycotoxins on the immune system reduce production and performance resulting in economic losses to poultry industries. Caution must be exercised while feeding grains contaminated with mycotoxins.

The intestine as a possible target for fumonisin toxicity

Fumonisins constitute a family of toxic and carcinogenic mycotoxins produced by Fusarium verticillioides (formerly F. moniliforme), a common fungal contaminant of corn. Contamination with fumonisin B(1) (FB(1)) is of concern as this mycotoxin causes various animal diseases. The gastrointestinal tract represents the first barrier against ingested chemicals, food contaminants, and natural toxins. Following ingestion of fumonisin-contaminated food or feed, intestinal epithelial cells could be exposed to a high concentration of toxin. In this review, we have summarized the data dealing with the impact of FB(1) on the intestine. Although FB(1 )is poorly absorbed and metabolized in the intestine, it induces intestinal disturbances (abdominal pain or diarrhea) and causes extra-intestinal organ pathologies (pulmonary edema, leukoencephalomalacia, or neural tube defects). The main toxicological effect of FB(1) reported in vivo and in vitro is the accumulation of sphingoid bases associated with the depletion of complex sphingolipids. This disturbance of the sphingolipid biosynthesis pathway could explain the other observed toxicological effects such as an alteration in intestinal epithelial cell viability and proliferation, a modification of cytokine production, and a modulation of intestinal physical barrier function.

Effects of feeding Fusarium verticillioides (formerly Fusarium moniliforme) culture material containing known levels of fumonisin B1 in Japanese quail (Coturnix coturnix japonica)

One hundred fifty 1-d-old quail chicks (Coturnix coturnix japonica) were divided into 2 groups. The 2 groups were designated as controls (CX) and fumonisin-fed birds (FX) with each containing 50 and 100 chicks, respectively. The birds in group CX were maintained on quail mash alone, whereas the birds in group FX were maintained on diets supplemented with 300 ppm of fumonisin B1 from Fusarium verticillioides (formerly Fusarium moniliforme) culture material from 1 d. Quail chicks in both groups were examined daily for clinical signs and mortality. Five randomly selected quail from each group were individually weighed on 0, 7, 14, 21, and 28 d post-feeding (DPF). After weighing, blood was collected from these birds at 7, 14, 21, and 28 DPF for hematological studies and at 14, 21, and 28 DPF for biochemical studies. Fumonisin B1-fed birds (FX) had ruffled feathers, reduced feed and water intake, poor body growth, and greenish mucus diarrhea with 59% mortality. Nearly 30% of the fumonisin B1-fed birds showed nervous signs during the 4-wk experimental period. From 7 DPF onward, BW in group FX were significantly lower than those in group CX. Fumonisin feeding significantly increased hemoglobin, packed cell volume, total erythrocyte count, and total leukocyte count. There was also a significant increase in aspartate transaminase and alanine transaminase in the fumonisin-fed group. Fumonisins significantly increased concentrations of total serum protein and albumin on 14 and 21 DPF, serum calcium and cholesterol levels from 14 DPF onward, and creatinine from 21 DPF onward. This study revealed that the addition of F. verticillioides culture material supplying a level of 300 ppm of FB1/kg of diet is highly toxic to quail chicks, resulting in heavy mortality, decreased growth rate, and significant alterations in hemato-biochemical parameters.

Individual and Combined Effects of Fusarium moniliforme Culture Material, Containing Known Levels of Fumonisin B1, and Salmonella Gallinarum Infection on Liver of Japanese Quail

Three hundred day-old Japanese quail (Coturnix coturnix japonica) were divided into two groups with 150 quail in each group. One group was maintained on quail mash alone, while Fusarium moniliforme culture material was added to quail mash in the second group from day 5 of age and was supplied at a rate of 150 ppm fumonisin B1 (FB1)/kg mash. At day 21, each group was further subdivided into two groups, yielding four groups with 75 birds apiece, which served as the control (group CX), the Salmonella Gallinarum alone group (group CS), the FB1 alone group (group FX), and the group fed FB1 and infected with Salmonella Gallinarum (group FS). An oral challenge with Salmonella Gallinarum organisms (2 x 10(4) colony-forming units/ml) was given to groups CS and FS at 21 days of age. Three quail each were necropsied on day 21 (0 day interval) from groups CX and FX only. At subsequent intervals (i.e., 1, 2, 3, 5, 7, 10, 14, and 21 days postinfection [DPI]), three quail were euthanatized from all four groups (CX, CS, FX, and FS). The gross and microscopic lesions were recorded in both mortality and euthanatized birds at the above intervals. The ultrastructural studies were done at 5 DPI. Mild to moderate hepatomegaly and pale discoloration of liver were observed in group FX, while congestion, hemorrhages, necrosis, and mild to severe hepatomegaly were the predominant gross lesions in both infected groups (CS and FS). The gross lesions in quail inoculated with Salmonella Gallinarum alone (group CS) generally developed slowly, appeared more widely scattered, and involved comparatively less surface area in contrast to the rapidly progressive and frequently confluent lesions in the combination group (FS), especially in the first 5 days of infection. Mild to marked hepatocellular swelling, multifocal hepatic necrosis, and hepatocellular and bile duct hyperplasia were the characteristic microscopic changes in the FX group. Microscopic lesions in quail of group CS comprised congestion, vacuolar changes, and focal necrosis in early stages, followed by granulomatous lesions at later intervals. Similar but more severe lesions were observed in the combination group (FS). Based on transmission electron microscopy, the maximum effect of FB1 toxicity was observed on mitochondria and endoplasmic reticulum. In general, the mitochondriae showed diverse form and structure, some of which appeared to lose their intact outer membrane, and the mitochondrial cristae were disoriented. The deformity in the cisternae structure of rough endoplasmic reticulum, with their rearrangement into round or tubular forms either bearing granular surface or leading to accumulation of smooth endoplasmic reticulum, was evident only in groups FX and FS. We conclude that the continuous presence of fumonisins in the diets of young quail might increase their susceptibility to or the severity of Salmonella Gallinarum infection.