Qualifying the T-2 Toxin-Degrading Properties of Seven Microbes with Zebrafish Embryo Microinjection Method

Evaluating the In Vivo Virulence of Environmental Pseudomonas aeruginosa Using Microinjection Model of Zebrafish (Danio rerio)

(1) Background: Microinjection of zebrafish (Danio rerio) embryos offers a promising model for studying the virulence and potential environmental risks associated with Pseudomonas aeruginosa. (2) Methods: This work aimed to develop a P. aeruginosa infection model using two parallel exposition pathways on zebrafish larvae with microinjection into the yolk and the perivitelline space to simultaneously detect the invasive and cytotoxic features of the examined strains. The microinjection infection model was validated with 15 environmental and clinical strains of P. aeruginosa of various origins, antibiotic resistance profiles, genotypes and phenotypes: both exposition pathways were optimized with a series of bacterial dilutions, different drop sizes (injection volumes) and incubation periods. Besides mortality, sublethal symptoms of the treated embryos were detected and analyzed. (3) Results: According to the statistical evaluation of our results, the optimal parameters (dilution, drop size and incubation period) were determined. (4) Conclusions: The tested zebrafish embryo microinjection infection model is now ready for use to determine the in vivo virulence and ecological risk of environmental P. aeruginosa.

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.

T-2 Toxin-The Most Toxic Trichothecene Mycotoxin: Metabolism, Toxicity, and Decontamination Strategies

Among trichothecenes, T-2 toxin is the most toxic fungal secondary metabolite produced by different Fusarium species. Moreover, T-2 is the most common cause of poisoning that results from the consumption of contaminated cereal-based food and feed reported among humans and animals. The food and feed most contaminated with T-2 toxin is made from wheat, barley, rye, oats, and maize. After exposition or ingestion, T-2 is immediately absorbed from the alimentary tract or through the respiratory mucosal membranes and transported to the liver as a primary organ responsible for toxin's metabolism. Depending on the age, way of exposure, and dosage, intoxication manifests by vomiting, feed refusal, stomach necrosis, and skin irritation, which is rarely observed in case of mycotoxins intoxication. In order to eliminate T-2 toxin, various decontamination techniques have been found to mitigate the concentration of T-2 toxin in agricultural commodities. However, it is believed that 100% degradation of this toxin could be not possible. In this review, T-2 toxin toxicity, metabolism, and decontamination strategies are presented and discussed.

Evaluation of the Multimycotoxin-Degrading Efficiency of Rhodococcus erythropolis NI1 Strain with the Three-Step Zebrafish Microinjection Method

The multimycotoxin-degrading efficiency of the Rhodococcus erythropolis NI1 strain was investigated with a previously developed three-step method. NI1 bacterial metabolites, single and combined mycotoxins and their NI1 degradation products, were injected into one cell stage zebrafish embryos in the same doses. Toxic and interaction effects were supplemented with UHPLC-MS/MS measurement of toxin concentrations. Results showed that the NI1 strain was able to degrade mycotoxins and their mixtures in different proportions, where a higher ratio of mycotoxins were reduced in combination than single ones. The NI1 strain reduced the toxic effects of mycotoxins and mixtures, except for the AFB1+T-2 mixture. Degradation products of the AFB1+T-2 mixture by the NI1 strain were more toxic than the initial AFB1+T-2 mixture, while the analytical results showed very high degradation, which means that the NI1 strain degraded this mixture to toxic degradation products. The NI1 strain was able to detoxify the AFB1, ZEN, T-2 toxins and mixtures (except for AFB1+T-2 mixture) during the degradation experiments, which means that the NI1 strain degraded these to non-toxic degradation products. The results demonstrate that single exposures of mycotoxins were very toxic. The combined exposure of mycotoxins had synergistic effects, except for ZEN+T-2 and AFB1+ZEN +T-2, whose mixtures had very strong antagonistic effects.