RESUMO
The zebrafish embryo test has been discussed as an alternative test system to provide data on acute fish toxicity required by diverse regulations. A meta-analysis of zebrafish embryo acute toxicity (ZFET) data has revealed conflicting evidence that narcotic compounds (i.e. compounds with baseline toxicity) may exhibit weaker sensitivity in the ZFET if compared to the acute (adult) fish toxicity test (AFT). Therefore, six compounds with presumably narcotic or unknown mode of action, and for which a previous meta-analysis has indicated weaker sensitivity were experimentally analysed for their fish embryo acute toxicity and exposure concentrations were monitored. The data indicated that ZFET and AFT for the selected compounds revealed similar sensitivity and differences were in the range of species differences of the AFT.