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Background: Although humans and animals are often simultaneously exposed to a variety of mycotoxins via feed and food consumption, in which aflatoxin B1 (AFB1) and deoxynivalenol (DON) is one of the most prevalent combination of mycotoxins. Many toxicological studies have merely focused on the impacts of single mycotoxins. In the present study, the combined toxicity and the related mechanism of AFB1 and DON to zebrafish (Danio rerio) were investigated. Results: Results exhibited that DON had lower toxicity to embryonic zebrafish with a 7-day LC50 of 218.3 mg a.i. L−1 in comparison to AFB1 (0.031 mg a.i. L−1). The mixture of AFB1 and DON elicited an additive combined effect on zebrafish embryos. The levels of CAT, caspase-3, and T4 markedly varied in most single and mixture groups. The expressions of four genes (cas3, apaf-1, cc-chem, and cyp19a) associated with oxidative stress, cellular apoptosis, immune system, and endocrine system were markedly varied upon the mixture exposure in comparison to the corresponding single exposure of AFB1 or DON. Conclusions: Our results revealed that the impacts of a mixture could not be estimated solely based on toxicities of the single mycotoxins. Taken together, our comprehensive investigation on the mycotoxin mixtures and their potential mechanisms could better reflect the reality of mycotoxin contamination in food and feed. [ABSTRACT FROM AUTHOR]

To examine pesticide mixture toxicity to aqueous organisms, we assessed the single and combined toxicities of thiamethoxam and other four pesticides (chlorpyrifos, beta-cypermethrin, tetraconazole, and azoxystrobin) to the rare minnow (Gobiocypris rarus). Data from 96-h semi-static toxicity assays of various developmental phases (embryonic, larval, juvenile, and adult phases) showed that beta-cypermethrin, chlorpyrifos, and azoxystrobin had the highest toxicities to G. rarus, and their LC50 values ranged from 0.0031 to 0.86 mg a.i. L−1, from 0.016 to 6.38 mg a.i. L−1, and from 0.39 to 1.08 mg a.i. L−1, respectively. Tetraconazole displayed a comparatively high toxicity, and its LC50 values ranged from 3.48 to 16.73 mg a.i. L−1. By contrast, thiamethoxam exhibited the lowest toxic effect with LC50 values ranging from 37.85 to 351.9 mg a.i. L−1. Rare minnow larvae were more sensitive than embryos to all the pesticides tested. Our data showed that a pesticide mixture of thiamethoxam–tetraconazole elicited synergetic toxicity to G. rarus. Moreover, pesticide mixtures containing beta-cypermethrin in combination with chlorpyrifos or tetraconazole also had synergetic toxicities to fish. The majority of pesticides are presumed to have additive toxicity, while our data emphasized that the concurrent existence of some chemicals in the aqueous circumstance could cause synergetic toxic effect, leading to severe loss to the aqueous environments in comparison with their single toxicities. Thence, the synergetic impacts of chemical mixtures should be considered when assessing the ecological risk of chemicals. [ABSTRACT FROM AUTHOR]