Effect of dietary T-2 fusariotoxin concentrations on the health and production of white Pekin duck broilers

Pathological consequences, metabolism and toxic effects of trichothecene T-2 toxin in poultry

Contamination of feed with mycotoxins has become a severe issue worldwide. Among the most prevalent trichothecene mycotoxins, T-2 toxin is of particular importance for livestock production, including poultry posing a significant threat to animal health and productivity. This review article aims to comprehensively analyze the pathological consequences, metabolism, and toxic effects of T-2 toxin in poultry. Trichothecene mycotoxins, primarily produced by Fusarium species, are notorious for their potent toxicity. T-2 toxin exhibits a broad spectrum of negative effects on poultry species, leading to substantial economic losses as well as concerns about animal welfare and food safety in modern agriculture. T-2 toxin exposure easily results in negative pathological consequences in the gastrointestinal tract, as well as in parenchymal tissues like the liver (as the key organ for its metabolism), kidneys, or reproductive organs. In addition, it also intensely damages immune system-related tissues such as the spleen, the bursa of Fabricius, or the thymus causing immunosuppression and increasing the susceptibility of the animals to infectious diseases, as well as making immunization programs less effective. The toxin also damages cellular processes on the transcriptional and translational levels and induces apoptosis through the activation of numerous cellular signaling cascades. Furthermore, according to recent studies, besides the direct effects on the abovementioned processes, T-2 toxin induces the production of reactive molecules and free radicals resulting in oxidative distress and concomitantly occurring cellular damage. In conclusion, this review article provides a complex and detailed overview of the metabolism, pathological consequences, mechanism of action as well as the immunomodulatory and oxidative stress-related effects of T-2 toxin. Understanding these effects in poultry is crucial for developing strategies to mitigate the impact of the T-2 toxin on avian health and food safety in the future.

Effects of T-2 toxin on growth performance, feather quality, tibia development and blood parameters in Yangzhou goslings

T-2 toxin is a dangerous natural pollutant and widely exists in animal feed, often causing toxic damage to poultry, such as slow growth and development, immunosuppression, and death. Although geese are considered the most sensitive poultry to T-2 toxin, the exact damage caused by T-2 toxin to geese is elusive. In the present study, a total of forty two 1-day-old healthy Yangzhou male goslings were randomly allotted seven diets contaminated with 0, 0.2, 0.4, 0.6, 0.8, 1.0, or 2.0 mg/kg T-2 toxin for 21 d, and the effects of T-2 toxin exposure on growth performance, feather quality, tibia development, and blood parameters were investigated. The results showed that T-2 toxin exposure significantly inhibited feed intake, body weight gain, shank length growth, and organ development (e.g., ileum, cecum, liver, spleen, bursa, and tibia) in a dose-dependent manner. In addition, the more serious feathering abnormalities and feather damage were observed in goslings exposed to a high dose of T-2 toxin (0.8, 1.0, and 2.0 mg/kg), which were mainly sparsely covered with short, dry, rough, curly, and gloss-free feathers on the back. We also found that hypertrophic chondrocytes of the tibial growth plate exhibited abnormal morphology and nuclear consolidation or loss, accompanied by necrosis and excessive apoptosis under 2.0 mg/kg T-2 toxin exposure. Moreover, 2.0 mg/kg T-2 toxin exposure triggered erythropenia, thrombocytosis, alanine aminotransferase, and aspartate aminotransferase activity, as well as high blood urea nitrogen, uric acid, and lactic dehydrogenase levels. Collectively, these data indicate that T-2 toxin had an adverse effect on the growth performance, feather quality, and tibia development, and caused liver and kidney damage and abnormal blood parameters in Yangzhou goslings, providing crucial information toward the prevention and control of T-2 toxin contamination in poultry feed.

Toxicity and detoxification of T-2 toxin in poultry

This review summarizes the updated knowledge on the toxicity of T-2 on poultry, followed by potential strategies for detoxification of T-2 in poultry diet. The toxic effects of T-2 on poultry include cytotoxicity, genotoxicity, metabolism modulation, immunotoxicity, hepatotoxicity, gastrointestinal toxicity, skeletal toxicity, nephrotoxicity, reproductive toxicity, neurotoxicity, etc. Cytotoxicity is the primary toxicity of T-2, characterized by inhibiting protein and nucleic acid synthesis, altering the cell cycle, inducing oxidative stress, apoptosis and necrosis, which lead to damages of immune organs, liver, digestive tract, bone, kidney, etc., resulting in pathological changes and impaired physiological functions of these organs. Glutathione redox system, superoxide dismutase, catalase and autophagy are protective mechanisms against oxidative stress and apoptosis, and can compensate the pathological changes and physiological functions impaired by T-2 to some degree. T-2 detoxifying agents for poultry feeds include adsorbing agents (e.g., aluminosilicate-based clays and microbial cell wall), biotransforming agents (e.g., Eubacterium sp. BBSH 797 strain), and indirect detoxifying agents (e.g., plant-derived antioxidants). These T-2 detoxifying agents could alleviate different pathological changes to different degrees, and multi-component T-2 detoxifying agents can likely provide more comprehensive protection against the toxicity of T-2.

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

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

The response of glandular gastric transcriptome to T-2 toxin in chicks

This study was conducted to determine the effect of T-2 toxin on the transcriptome of the glandular stomach in chicks using RNA-sequencing (RNA-Seq). Four groups of 1-day-old Cobb male broilers (n = 4 cages/group, 6 chicks/cage) were fed a corn-soybean-based diet (control) and control supplemented with T-2 toxin at 1.0, 3.0, and 6.0 mg/kg, respectively, for 2 weeks. The histological results showed that dietary supplementation of T-2 toxin at 3.0 and 6.0 mg/kg induced glandular gastric injury including serious inflammation, increased inflammatory cells, mucosal edema, and necrosis and desquamation of the epithelial cells in the glandular stomach of chicks. RNA-Seq analysis revealed that there were 671, 1393, and 1394 genes displayed ≥2 (P < 0.05) differential expression in the dietary supplemental T-2 toxin at 1.0, 3.0, and 6.0 mg/kg, respectively, compared with the control group. Notably, 204 differently expressed genes had shared similar changes among these three doses of T-2 toxin. GO and KEGG pathway analysis results showed that many genes involved in oxidation-reduction process, inflammation, wound healing/bleeding, and apoptosis/carcinogenesis were affected by T-2 toxin exposure. In conclusion, this study systematically elucidated toxic mechanisms of T-2 toxin on the glandular stomach, which might provide novel ideas to prevent adverse effects of T-2 toxin in chicks.

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.

Role of Glutathione Redox System on the T-2 Toxin Tolerance of Pheasant (Phasianus colchicus)

The purpose of the present study was to evaluate the effects of different dietary concentrations of T-2 toxin on blood plasma protein content, lipid peroxidation and glutathione redox system of pheasant (Phasianus colchicus). A total of 320 one-day-old female pheasants were randomly assigned to four treatment groups fed with a diet contaminated with different concentrations of T-2 toxin (control, 4 mg/kg, 8 mg/kg and 16 mg/kg). Birds were sacrificed at early (12, 24 and 72 hr) and late (1, 2 and 3 weeks) stages of the experiment to demonstrate the effect of T-2 toxin on lipid peroxidation and glutathione redox status in different tissues. Feed refusal and impaired growth were observed with dose dependent manner. Lipid-peroxidation was not induced in the liver, while the glutathione redox system was activated partly in the liver, but primarily in the blood plasma. Glutathione peroxidase activity has changed parallel with reduced glutathione concentration in all tissues. Based on our results, pheasants seem to have higher tolerance to T-2 toxin than other avian species, and glutathione redox system might contribute in some extent to this higher tolerance, in particular against free-radical mediated oxidative damage of tissues, such as liver.

T-2 mycotoxin: toxicological effects and decontamination strategies

Mycotoxins are highly diverse secondary metabolites produced in nature by a wide variety of fungus which causes food contamination, resulting in mycotoxicosis in animals and humans. In particular, trichothecenes mycotoxin produced by genus fusarium is agriculturally more important worldwide due to the potential health hazards they pose. It is mainly metabolized and eliminated after ingestion, yielding more than 20 metabolites with the hydroxy trichothecenes-2 toxin being the major metabolite. Trichothecene is hazardously intoxicating due to their additional potential to be topically absorbed, and their metabolites affect the gastrointestinal tract, skin, kidney, liver, and immune and hematopoietic progenitor cellular systems. Sensitivity to this type of toxin varying from dairy cattle to pigs, with the most sensitive endpoints being neural, reproductive, immunological and hematological effects. The mechanism of action mainly consists of the inhibition of protein synthesis and oxidative damage to cells followed by the disruption of nucleic acid synthesis and ensuing apoptosis. In this review, the possible hazards, historical significance, toxicokinetics, and the genotoxic and cytotoxic effects along with regulatory guidelines and recommendations pertaining to the trichothecene mycotoxin are discussed. Furthermore, various techniques utilized for toxin determination, pathophysiology, prophylaxis and treatment using herbal antioxidant compounds and regulatory guidelines and recommendations are reviewed. The prospects of the trichothecene as potential hazardous agents, decontamination strategies and future perspectives along with plausible therapeutic uses are comprehensively described.

Effect of garlic oil supplementation on the glutathione redox system of broiler chickens fed with T-2 toxin contaminated feed

The aim of present study was to investigate whether garlic essential oil with natural organosulfur compounds that possess free radical scavenging activity is able to alleviate the adverse effects of T-2 toxin. In a two-weeks feeding trial with 14-day old Cobb cockerels (n=15 per group) housed in batteries, twelve experimental treatments were applied. The basal diet was experimentally contaminated with T-2 toxin at concentrations of 0, 0.52, 1.05 or 2.05 mg/kg and at each contamination level garlic oil was added at a dosage rate of 0, 0.3 or 1.5 g/kg, respectively. The experimental diets were fed for 14 days. In the first week of the trial, production traits showed numerically lower body weights, a lower feed intake, and subsequently higher feed to gain ratios in the animals exposed to T-2 toxin-contaminated diets. This effect became non-significant in the second week. Garlic oil supplementation at the lower dose of 0.3 mg/kg resulted in a significantly lower body weight gain at the highest T-2 toxin contamination level. The malondialdehyde concentration did not show any dose-related changes. The level of reduced glutathione was significantly higher in blood plasma as a result of the lower (0.3 g/kg) garlic oil supplementation and as an effect of T-2 toxin challenge in red blood cell haemolysate. Glutathione peroxidase activity showed the same trend. The results showed that the lower (0.3 g/kg) but not the higher (1.5 g/kg) dose of garlic oil supplementation had desirable effects on the measured redox parameters, eliminating some of the adverse effects of feeding T-2 toxin contaminated diet.

T-2 toxin, a trichothecene mycotoxin: review of toxicity, metabolism, and analytical methods

This review focuses on the toxicity and metabolism of T-2 toxin and analytical methods used for the determination of T-2 toxin. Among the naturally occurring trichothecenes in food and feed, T-2 toxin is a cytotoxic fungal secondary metabolite produced by various species of Fusarium. Following ingestion, T-2 toxin causes acute and chronic toxicity and induces apoptosis in the immune system and fetal tissues. T-2 toxin is usually metabolized and eliminated after ingestion, yielding more than 20 metabolites. Consequently, there is a possibility of human consumption of animal products contaminated with T-2 toxin and its metabolites. Several methods for the determination of T-2 toxin based on traditional chromatographic, immunoassay, or mass spectroscopy techniques are described. This review will contribute to a better understanding of T-2 toxin exposure in animals and humans and T-2 toxin metabolism, toxicity, and analytical methods, which may be useful in risk assessment and control of T-2 toxin exposure.

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.

Novel strategies to control mycotoxins in feeds: a review

Mycotoxin-producing fungi may contaminate agricultural products in the field (preharvest spoilage), during storage (postharvest spoilage), or during processing. Mycotoxin contamination of foods and feeds poses serious health hazard to animals and humans. For lowering mycotoxin contamination of feeds and foods, several strategies have been investigated that can be divided into biological, chemical and physical methods. This paper gives an overview of strategies which are promising with regard to lowering the mycotoxin burden of animals and humans.

Effects of graded levels ofFusarium-toxin-contaminated wheat in Pekin duck diets on performance, health and metabolism of deoxynivalenol and zearalenone

1. Diets with increasing proportions of Fusarium-toxin-contaminated wheat were fed to Pekin ducks for 49 d in order to titrate the lowest effect level. Dietary deoxynivalenol (DON) and zearalenone (ZON) concentrations were successively increased up to 6 to 7 mg/kg and 0.05 to 0.06 mg/kg, respectively. 2. Feed intake, live weight gain and feed to gain ratio were not influenced by dietary treatment. 3. Gross macroscopic inspection of the upper digestive tract did not reveal any signs of irritation, inflammation or other pathological changes. The weight of the bursa of Fabricius, relative to live weight, decreased in a dose-related fashion. Activities of glutamate dehydrogenase and gamma-glutamyl-transferase in serum were either unaffected or inconsistently affected by dietary treatments. 4. Concentrations of DON and of its de-epoxydised metabolite in plasma and bile were lower than the detection limits of 6 and 16 ng/ml, respectively, of the applied high performance liquid chromatography (HPLC) method. 5. ZON or its metabolites were not detectable in plasma and livers (detection limits of the HPLC method were 1, 0.5 and 5 ng/g for ZON, alpha-zearalenol (alpha-ZOL) and beta-zearalenol (beta-ZOL), respectively). Concentrations of ZON, alpha-ZOL and beta-ZOL in bile increased linearly with dietary ZON concentration. The mean proportions of ZON, alpha-ZOL and beta-ZOL of the sum of all three metabolites were 80, 16 and 4%, respectively. 6. Taken together, it can be concluded that dietary DON and ZON concentrations up to 6 and 0.06 mg/kg, respectively, did not adversely affect performance and health of growing Pekin ducks.