Alterations in Daphnia magna exposed to enniatin B and beauvericin provide additional value as environmental indicators

Abstract

Mycotoxins beauvericin (BEA) and enniatin B (ENN B) affect negatively several systems and demand more studies as the mechanisms are still unclear. The simultaneous presence of contaminants in the environment manifests consequences of exposure for both animals and flora. Daphnia magna is considered an ideal invertebrate to detect effects of toxic compounds and environmental alterations. In this study, the potential toxicity and the basic mechanism of BEA and ENN B individually and combined were studied in D. magna. Acute and delayed toxicity were evaluated, and transcript levels of genes involved in xenobiotic metabolism (mox, gst, abcb1, and abcc5), reproduction, and oxidative stress (vtg-SOD) were analyzed by qPCR. Though no acute toxicity was found, results revealed a spinning around and circular profile of swimming, a strong decrease of survival after 72 h for BEA and ENN B at 16 µM and 6.25 µM, respectively, while for BEA + ENN B [8 + 1.6] µM after 96 h. The amount of mycotoxin remaining in the media revealed that the higher the concentration assayed the higher the amount remaining in the media. Differential regulation of genes suggests that xenobiotic metabolism is affected denoting different effects on transcription for tested mycotoxins. The results provide new insights into the underlying risk assessment of BEA and ENN B not only through food for consumers but also for the environment.