THE EFFECT OF LEAD ON THE DEVELOPMENT OF EMBRYOS AND LARVAE OF DANIO RERIO

The early stages of development of aquatic organisms, including fish, are inherently vulnerable to the effects of lead (Pb) and other water-polluting metals. However, reports of harmful effects of environmentally significant Pb levels are limited. To this end, we exposed the embryos of old Danio rerio fish 2.5 hours after fertilization (hours) to a range of Pb concentrations covering environmentally significant levels (10 μm; 20 μm; 40 μm; 60 μm), up to 120h. Exposure negatively affected the development and survival of the embryos of danio fish, causing mortality associated with embryo coagulation, depending on concentration. At 24 hpf, the highest level of exposure (60 μm Pb) led to impaired embryo activity, characterized by a decrease in burst activity and the number of movements performed by embryos per minute. At 72 hpf, all the embryos hatched in all exposure concentrations. Morphological abnormalities and an increase in mRNA expression were observed. These results indicate that the Pb content within ecologically significant levels may be harmful to developing danio fish.