CYANOBACTERIA FROM SHKODRA LAKE AND HISTOLOGY OF LARVAE HYPOPHTHALMICHTHYS MOLITRIX (Valenciennes 1844)

The aim of this study was to find out how crude extract of cyanobacteria can influence larval development of hypophthalmichthys on the basis of embryo-larval toxicity test and histological changes of liver of larvae hypophthalmichthys aexposed 30 days to the crude extract of cyanobacteria with the cumulative concentration 9.0 μg l-1 (medium concentration of the extract) and 0.9 μg l-1 (low concentration of the extract) of microcystins LR, RR and YR. The experiments were finished after 30 days. Evaluation of the tests was based on the OECD guideline for testing chemicals, direction 210 from 1992. Liver sections were stained with haematoxylin-eosin and using light microscopy. The extract with medium concentration caused an increase in malformed and dead larvae. The extract with low concentration caused an increase in dead larvae. Vacuolisation of hepatocytes accompanied by damage of nuclei (pyknosis,) were found in the group exposed to the low concentration of the extract. Necroses of hepatocytes with vacuolization and nuclei damage (pyknosis, karyolysis,) were found in the group exposed to the medium concentration of the extract. The degree of damage depended on the concentration of the extract.