Volume No. 7 Issue No.: 4 Page No.: 1381-1384 April-June 2013




Golemi S., Medja N.*1 and Kraja J.2

1. Department of Biology-Chemistry, University of Shkodra (ALBANIA)
2. Department of Nursery, University of Shkodra (ALBANIA)


Received on : November 10, 2012




Cyanobacteria and their toxic products represent a serious problem in many waters. The aim of this study was to find out how crude extract of cyanobacteria can influence the embryo-larval development of carassius on the basis of embryo-larval toxicity test. Crude extract of cyanobacteria containing the known amount of microcystins LR, YR and RR (90, 9.0 and 0.9 μgL-1, i.e. high, medium and low concentration of the extract), was administered to carassius eggs. The experiments were finished after 8 days short- term exposure. Evaluation of the tests was based on the OECD guideline for testing chemicals, direction 210 from 1992. The extract with high concentration caused 93.5% embryonic mortality, prolonged hatching, increased numbers of malformed and dead larvae and a decrease in average total length. Yolk sac dropsy were observed. Tissue sections were stained with haematoxylin-eosin and examined using light microscopy. Changes of liver, in particular, were examined. No histopathological changes were found in control or experimental groups after the short-term exposure except for non-resorbed yolk sacks in the group exposed to the high concentration of the extract. The development had been retarded in this group.


Keywords : Cyanobacteria, Malformations, Fish, Toxicity test, Crude extract, OECD guidelines