Brain and liver histopathological examination of carassius gibelio from a newly reconstructed lake with toxic cyanobacteria

Abstract

Lake Karla, Greece, is a partially reconstructed lake. The lake's water filling process started in September 2009. Existing evidence based on the prevailing microorganisms and cyanotoxin levels in the lake in 2010 suggested that the lake could have a negative effect on its biota. By investigating whether Carassius gibelio individuals bear brain and liver histopathological findings, this study complements the data now available from the first year of L. Karla's reconstruction. Based on the 16S rRNA gene diversity, the potentially toxic cyanobacteria Anabaenopsis sp. and Planktothrix were shown to be present in the lake's water in May 2011. C. gibelio specimens were collected a month later. Histopathological alterations in the liver of the individuals, namely picnotic nuclei, loss of structure and hemorrhagic regions, were detected by microscopic examination. Picnotic nuclei, loss of the liver structure and hemorrhagic regions were detected. These alterations may be associated with the occurrence of cyanobacterial toxins possibly produced by the potentially toxic cyanobacterial species found in the water column. No alterations were found in the brain, probably due to the existence of the blood-brain barrier. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey.