Embryotoxic effect of Deltamethrin on the zebrafish, Danio rerio

INTRODUCTION: The effect of Deltamethrin (from 10-1 to 5.10+9 pg/l), drug utilised in intensive aquaculture[1-2], has been evaluated by determining death rate and alterations of embrionic development, in particular on the nervous system. As a test organism Danio rerio was chosen, being a very useful organism to evaluate embryotoxicity of several different compounds[3-4]. RESULTS: Death rate after 7 days ranged from about 70% up to 100%, respectively from 10-1 to 10+9 pg/l and from 1.25 to 5.10+9 pg/l. By the 1st day from the start of the experiment, animals showed progressively evident motility alterations, up to complete paralyse and death, after the 6th day. Deltametrin also induces reduced pigmentation, cephalic/trunk alterations and lack of yolk sack resorbment. Immuno-hystochemical observations evidenced abnormal neuronal phenotype[5]. CONCLUSIONS: These results can give account of the possible effect on non target species of the therapeutic and prophylactic practices involved in ectoparasite control.