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.

Lactobacillus plantarum and Deoxynivalenol Detoxification: A Concise Review

ABSTRACT

Mycotoxins are toxic secondary fungal metabolites that contaminate feeds, and their levels remain stable during feed processing. The economic impact of mycotoxins on animal production happens mainly due to losses related to direct effects on animal health and trade losses related to grain rejection. Deoxynivalenol (DON) is a trichothecene mycotoxin that has contaminated approximately 60% of the grains worldwide. Ingestion of DON induces many toxic effects on human and animal health. Detoxification strategies to decrease DON levels in food and feeds include physical and chemical methods; however, they are not very effective when incorporated into the industrial production process. A valuable alternative to achieve this aim is the use of lactic acid bacteria. These bacteria can control fungal growth and thus overcome DON production or can detoxify the mycotoxin through adsorption and biotransformation. Some Lactobacillus spp. strains, such as Lactobacillus plantarum, have demonstrated preventive effects against DON toxicity in poultry and swine. This beneficial effect is associated with a binding capacity of lactic acid bacteria cell wall peptidoglycan with mycotoxins. Moreover, several antifungal compounds have been isolated from L. plantarum supernatants, including lactic, acetic, caproic, phenyl lactic, 3-hydroxylated fatty, and cyclic dipeptide acids. Biotransformation of DON by L. plantarum into other products is also hypothesized, but the mechanism remains unknown. In this concise review, we highlight the use of L. plantarum as an alternative approach to reduce DON levels and toxicity. Although the action mechanism of L. plantarum is still not fully understood, these bacteria are a safe, efficient, and low-cost strategy to reduce economic losses from mycotoxin contamination cases.

HIGHLIGHTS

Over-processed meat and bone meal and phytase effects on broilers challenged with subclinical necrotic enteritis: Part 3. Bone mineralization and litter quality

This study was conducted to determine the effect of necrotic enteritis (NE), phytase level and meat and bone meal (MBM) processing on bone mineralization of broilers and litter quality. Ross 308 male broiler chicks (n = 768) were allotted to 48 pens with 16 birds each. There were 8 dietary treatments in a 2 × 2 × 2 factorial arrangement. Factors were NE challenge (no or yes), phytase level (500 or 5,000 FTU/kg), and MBM (as-received or over-processed). Half of the birds were challenged with field strains of Eimeria spp. at d 9 and 10⁸ CFU per mL of Clostridium perfringens strain EHE-NE18 on d 14 and 15. The middle toe, tibia and femur of 2 birds per pen were excised at d 16 and 29 for determination of ash, breaking strength (BS) and bone mineralization. At d 42, all were assessed for hock burns and litter was scored and assessed for dry matter (DM). At d 16, challenged birds had lower toe ash (P < 0.01), femur ash (P < 0.001), tibia ash (P < 0.001) and tibial BS (P < 0.001) than unchallenged birds. At d 16, challenged birds fed high phytase and over-processed MBM had higher toe Mn than those fed low phytase and as-received MBM. At d 29 unchallenged birds fed high phytase and as-received MBM had a higher toe Mn than those fed over-processed MBM. At d 16, a phytase × MBM interaction was detected for femur Zn concentration (P < 0.05), where a higher level of Zn was observed in the high phytase group fed over-processed MBM. At d 16, tibial Ca (P < 0.05) and P (P < 0.05) were lower in the challenged whereas the femur K (P < 0.001), Mn (P < 0.01) and Na (P < 0.001) were higher in the challenged at d 16. At d 42, challenged birds had higher litter DM (P = 0.058) and fewer hock burns than those unchallenged (P < 0.05). In conclusion, NE impaired bone traits but high phytase and over-processed MBM increased bone mineral contents. Cases of hock burns may be lower under NE incidences due to lower livability of birds reducing litter wetness.

An update on T-2 toxin and its modified forms: metabolism, immunotoxicity mechanism, and human exposure assessment

T-2 toxin is the most toxic trichothecene mycotoxin, and it exerts potent toxic effects, including immunotoxicity, neurotoxicity, and reproductive toxicity. Recently, several novel metabolites, including 3',4'-dihydroxy-T-2 toxin and 4',4'-dihydroxy-T-2 toxin, have been uncovered. The enzymes CYP3A4 and carboxylesterase contribute to T-2 toxin metabolism, with 3'-hydroxy-T-2 toxin and HT-2 toxin as the corresponding primary products. Modified forms of T-2 toxin, including T-2-3-glucoside, exert their immunotoxic effects by signaling through JAK/STAT but not MAPK. T-2-3-glucoside results from hydrolyzation of the corresponding parent mycotoxin and other metabolites by the intestinal microbiota, which leads to enhanced toxicity. Increasing evidence has shown that autophagy, hypoxia-inducible factors, and exosomes are involved in T-2 toxin-induced immunotoxicity. Autophagy promotes the immunosuppression induced by T-2 toxin, and a complex crosstalk between apoptosis and autophagy exists. Very recently, "immune evasion" activity was reported to be associated with this toxin; this activity is initiated inside cells and allows pathogens to escape the host immune response. Moreover, T-2 toxin has the potential to trigger hypoxia in cells, which is related to activation of hypoxia-inducible factor and the release of exosomes, leading to immunotoxicity. Based on the data from a series of human exposure studies, free T-2 toxin, HT-2 toxin, and HT-2-4-glucuronide should be considered human T-2 toxin biomarkers in the urine. The present review focuses on novel findings related to the metabolism, immunotoxicity, and human exposure assessment of T-2 toxin and its modified forms. In particular, the immunotoxicity mechanisms of T-2 toxin and the toxicity mechanism of its modified form, as well as human T-2 toxin biomarkers, are discussed. This work will contribute to an improved understanding of the immunotoxicity mechanism of T-2 toxin and its modified forms.

Reference parameters of peripheral immune cell populations in broiler chickens using a large database

1. Peripheral blood immune evaluation of broilers by flow cytometry is commonly used in avian research. However, indicative immune parameters in healthy animals have not yet been determined. In this trial, confidence intervals were determined for several circulating immune cell subsets.2. The intervals were determined from over 1,000 healthy broilers from commercial lines. To verify the usefulness of the data, they were compared to animals under salmonellosis or mycotoxin challenges.3. Confidence intervals were determined for several immune cells in the peripheral blood of broilers. The importance of some immune cells in discriminating diseased from healthy controls was demonstrated.4. This work initiated the construction of reference values for cellular parameters in broilers as a tool for the avian immunology community. Accordingly, the entire dataset of healthy animals was made available for use with other analyses and for improvement by others.