Can Rodlet Cells Changes in Barbell (Barbus peloponnesius) From the River Bregalnica Be Used as Biomarkers of Environmental Contamination?

Abstract

For evaluating pollution impacts on aquatic ecosystems there is a need to establish early- warning signals (biomarkers) using bioindicator organisms. Some studies suggested that rodlet cells (RCs) changes in fish can be used as pollution biomarkers. Looking for supporting evidence, we quantitatively estimate the RCs amounts in liver, as well as general fish health indicators - the condition factor (CF) and hepato-somatic index (HSI) – in 136 barbell, caught at three locations (reference site and two sites – A and B – suspected to be under pollution impact) from the River Bregalnica. Fishes from site A showed significantly lower values for CF and HSI when compared with the other two locations, and highest average amount of RCs. Both the relative and total volumes of RCs significantly differed from those found at site B (p<0.05), but either site A or B was not statistically different from the reference site. Lower indices of condition (CF and HSI) at polluted localities were only partially associated with higher liver RCs counts. The present data indicated that RCs were a non-efficient bio-monitoring tool. However, further evaluation of these cells as potential biomarkers are necessary, as its behaviour may depend on the type of pollutants. Also, RCs exist in diverse organs and organ-specific responses can thus occur.