Effects of dietary Fusarium mycotoxins on intestinal lymphocyte subset populations, cell proliferation and histological changes in avian lymphoid organs

Multi-omics reveal mechanisms of high enteral starch diet mediated colonic dysbiosis via microbiome-host interactions in young ruminant

BACKGROUND

Although rumen development is crucial, hindgut undertakes a significant role in young ruminants' physiological development. High-starch diet is usually used to accelerate rumen development for young ruminants, but always leading to the enteral starch overload and hindgut dysbiosis. However, the mechanism behind remains unclear. The combination of colonic transcriptome, colonic luminal metabolome, and metagenome together with histological analysis was conducted using a goat model, with the aim to identify the potential molecular mechanisms behind the disrupted hindgut homeostasis by overload starch in young ruminants.

RESULT

Compared with low enteral starch diet (LES), high enteral starch diet (HES)-fed goats had significantly higher colonic pathology scores, and serum diamine oxidase activity, and meanwhile significantly decreased colonic mucosal Mucin-2 (MUC2) protein expression and fecal scores, evidencing the HES-triggered colonic systemic inflammation. The bacterial taxa Prevotella sp. P4-67, Prevotella sp. PINT, and Bacteroides sp. CAG:927, together with fungal taxa Fusarium vanettenii, Neocallimastix californiae, Fusarium sp. AF-8, Hypoxylon sp. EC38, and Fusarium pseudograminearum, and the involved microbial immune pathways including the "T cell receptor signaling pathway" were higher in the colon of HES goats. The integrated metagenome and host transcriptome analysis revealed that these taxa were associated with enhanced pathogenic ability, antigen processing and presentation, and stimulated T helper 2 cell (TH2)-mediated cytokine secretion functions in the colon of HES goats. Further luminal metabolomics analysis showed increased relative content of chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA), and decreased the relative content of hypoxanthine in colonic digesta of HES goats. These altered metabolites contributed to enhancing the expression of TH2-mediated inflammatory-related cytokine secretion including GATA Binding Protein 3 (GATA3), IL-5, and IL-13. Using the linear mixed effect model, the variation of MUC2 biosynthesis explained by the colonic bacteria, bacterial functions, fungi, fungal functions, and metabolites were 21.92, 20.76, 19.43, 12.08, and 44.22%, respectively. The variation of pathology scores explained by the colonic bacterial functions, fungal functions, and metabolites were 15.35, 17.61, and 57.06%.

CONCLUSIONS

Our findings revealed that enteral starch overload can trigger interrupted hindgut host-microbiome homeostasis that led to impaired mucosal, destroyed colonic water absorption, and TH2-mediated inflammatory process. Except for the colonic metabolites mostly contribute to the impaired mucosa, the nonnegligible contribution from fungi deserves more future studies focused on the fungal functions in hindgut dysbiosis of young ruminants. Video Abstract.

Levels of zearalenone and its metabolites in sun-dried kapenta fish and water of Lake Kariba in Zambia - A preliminary study

Contamination of food with mycotoxins and the associated possibilities of human intoxication is a serious problem in Africa. One of the most widespread mycotoxins is zearalenone (ZEN), which usually occurs in food of vegetable origin. On the other hand, information about ZEN in products of animal origin in African countries is extremely scanty. During the present study, levels of ZEN and its analogs: α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL) were measured by high performance liquid chromatography (HPLC) with fluorescence detection in sun-dried kapenta fish - traditional Zambian food, as well as in the water of Lake Kariba - the main source of kapenta fish in Zambia. This study revealed that levels of ZEN in sun-dried kapenta fish fluctuated from 27.2 μg·kg^-1 to 53.9 μg·kg^-1, whereas the contamination of water from Lake Kariba with ZEN is rather minimally similar to the content of ZEN analogs in both kapenta fish and water. The obtained results have shown that sun-dried kapenta fish of Lake Kariba contain ZEN and may contribute to the exposure of consumers to this substance.

Chronic Exposure to the Fusarium Mycotoxin Deoxynivalenol: Impact on Performance, Immune Organ, and Intestinal Integrity of Slow-Growing Chickens

This study investigates the long-term effects of deoxynivalenol (DON) consumption on avian growth performance, on the proliferation, apoptosis, and DNA damage of spleen cells, and on intestinal integrity. Two hundred and eight 5-day-old black-feathered Taiwan country chickens were fed diets containing 0, 2, 5, and 10 mg/kg of DON for 16 weeks. Body weight gain of male birds in the 2 mg/kg group was significantly lower than that in the 5 mg/kg group. At the end of trial, feeding DON-contaminated diets of 5 mg/kg resulted in heavier spleens. Moreover, the increase in DON induced cellular proliferation, apoptosis, and DNA damage signals in the spleen, the exception being female birds fed 10 mg/kg of DON showing reduced proliferation. Expression of claudin-5 was increased in jejunum of female birds fed 2 and 5 mg/kg of DON, whereas decreased expression levels were found in male birds. In conclusion, our results verified that DON may cause a disturbance to the immune system and alter the intestinal barrier in Taiwan country chickens, and may also lead to discrepancies in growth performances in a dose- and sex-dependent manner.

Changes in the Subpopulations of Porcine Peripheral Blood Lymphocytes Induced by Exposure to Low Doses of Zearalenone (ZEN) and Deoxynivalenol (DON)

Zearalenone and deoxynivalenol are secondary metabolites of fungi of the genus Fusarium. The presence of mycotoxins in cereals and the resulting contamination of feeds and foods pose health risks for animals and humans. The dangers associated with high doses of mycotoxins have been extensively researched but very little is known about NOAEL (No Observed Adverse Effect Level) doses or exposure to a combination of mycotoxins (mixed mycotoxicoses). The aim of this study was to determine the effects of six-week exposure to NOAEL doses of individual and combined mycotoxins on the subpopulations of CD4⁺8(-), CD4(-)8⁺ and CD4⁺8⁺ lymphocytes in the peripheral blood of pigs. The experiment was performed on 72 gilts with average body weight of 25 kg, divided into three experimental groups (E1, E2 and E3, administered zearalenone (ZEN), deoxynivalenol (DON) and ZEN + DON, respectively, on a daily basis) and a control group (C) receiving placebo. Changes in lymphocyte subpopulations were evaluated by flow cytometry at weekly intervals (experimental days 7, 14, 21, 28, 35 and 42). A linear increase in the percentage of CD4⁺8⁺ lymphocytes was highly correlated with time (r = 0.682) in group C. The correlations and linear increase in the above subpopulation were disrupted in the remaining groups. In group E3, a statistically significant (p < 0.05) decrease in CD4⁺8⁺ counts was observed in week 5, which could point to a transient depletion of regulatory mechanisms of immune responses. The noted results also suggest that in mixed mycotoxicosis, ZEN and DON exerted stronger immunomodulatory effects.

The Influence of Low Doses of Zearalenone on Distribution of Selected Active Substances in Nerve Fibers Within the Circular Muscle Layer of Porcine Ileum

The aim of this study was to investigate, whether low doses (25 % of no observable adverse effect levels values) of zearalenone (ZEN) can affect the expression of active substances in nerve fibers in the muscular layer of porcine ileum. The study was performed on ten immature pigs divided into two groups: experimental group (n = 5), where zearalenone (10 μg/kg body weight) was given for 42 days, and control animals (n = 5), where placebo was administered. Fragments of ileum of all animals were processed for single-labelling immunofluorescence technique using the antibodies against vasoactive intestinal peptide, neuronal form of nitric oxide synthase, cocaine and amphetamine regulatory peptide, galanin, pituitary adenylate cyclase-activating peptide-27 and substance P. The number of nerve fibers immunoreactive to particular substances was evaluated by the counting of nerves per observation field (0.1 mm²). Low doses of zearalenone caused the clear changes in the expression of substances studied. The number of nerve fibers immunoreactive to the majority of substances increased in experimental animals. The exception was only galanin, the expression of which was less after administration of zearalenone. The obtained results for the first time show that even low doses of zearalenone can affect the nerve fibers in the digestive tract.

The effects of feed-borne Fusarium mycotoxins and glucomannan in turkey poults based on specific and non-specific parameters

An experiment was conducted to investigate the effects of feeding grains naturally contaminated with Fusarium mycotoxins and a yeast derived glucomannan mycotoxin adsorbent (GMA) on selected specific and non-specific parameters in turkey poults. Two hundred and forty 1-day-old male turkey poults were fed the experimental diets for twelve weeks. Experimental diets were formulated with control grains, control grains+0.2% GMA, naturally-contaminated grains, or naturally-contaminated grains+0.2% GMA. Deoxynivalenol (DON) was the major contaminant of the contaminated grains and concentrations varied from 4.0 to 6.5 mg/kg in the contaminated diets. Non-specific parameters measured included: performance parameters, plasma biochemistry profiles, morphometry and CD8(+) T-lymphocyte counts in the duodenum. Plasma concentrations of DON and de-epoxydeoxynivalenol (DOM-1) were used as specific parameters. Performance parameters and plasma biochemistry were altered by the feeding of contaminated diets and GMA but this was not consistent throughout the trial. The feeding of contaminated diets reduced duodenal villus height and apparent villus surface area. This effect was prevented by GMA supplementation. The feeding of contaminated diets elevated total duodenal CD8(+) T-lymphocyte counts but this effect was not prevented by GMA. No significant differences were seen in plasma concentrations of DON and DOM-1 comparing birds fed contaminated and contaminated+GMA diets suggesting that GMA did not prevent DON absorption under these conditions.

Assessment of the potential of a boron-fructose additive in counteracting the toxic effect of Fusarium mycotoxins

Trichotecenes are mycotoxins produced by Fusarium sp., which may contaminate animal feeds and human food. A feeding trial was conducted to evaluate the effect of a fusarotoxin-contaminated diet, and to explore the counteracting potential of a calcium fructoborate (CFrB) additive on performance, typical health biochemistry parameters and immune response in weaned pigs. A naturally contaminated maize, containing low doses of deoxynivalenol, zearalenone, fumonisins and T-2/HT-2 toxins (1790, 20, 0·6 and 90 parts per billion), was included in a maize-soyabean meal diet, and given ad libitum to eight weaned piglets (two groups: four pigs/group) for a period of 24 d. CFrB was administered to one of the contaminated groups and to another four piglets as a daily supplement, following the manufacturer's recommendation. A decrease in performance was observed in contaminated animals at this concentration of feed toxins, which was ameliorated by the dietary CFrB supplementation. Fusarium toxins also altered the pig immune response by increasing (P < 0·05) the ex vivo peripheral blood mononuclear cell proliferation (111·7 % in comparison with control), the respiratory burst of porcine granulocytes (15·4 % for responsive cells v. 5·1 % for unstimulated cells and 70·95 v. 22·65 % for stimulated cells, respectively), the percentage of peripheral T, CD3(+), CD3(+)CD4(+) and CD3(+)CD8(+) subsets and the synthesis of IL-1β, TNF-α and IL-8 (123·8, 217·1 and 255·1 %, respectively). The diet containing the CFrB additive reduced these exacerbated cellular immune responses induced by Fusarium toxins. However, consumption of CFrB did not counteract the effect of mycotoxins on biochemistry parameters, and increased plasma IgM and IgG of contaminated pigs.