09 December 2017

Oleh and colleagues, 2017

Oleh M, Julia K, Zoya S, Olexandra N, Oleh N, Bogdan D. 2017. Parameters of the histological adaptation of Marmorkrebs Procambarus fallax f. virginal (sic) (Decapoda, Cambaridae) to zinc and cadmium ions pollution. World Scientific News 90: 189-202. http://www.worldscientificnews.com/wp-content/uploads/2017/08/WSN-90-2017-189-202.pdf

Abstract

Due to the fact that marbled crayfish (Marmorkrebs) got into the reservoirs of the Dnipropetrovsk region in 2015, it was necessary to study the possibilities of its adaptation to environmental factors of reservoirs for further prediction of its distribution or even acclimatization under conditions of toxicological contamination of the ponds of the steppe Prydniprovya. The article presents the results of studies on the influence of heavy metal ions on marbled crayfish. It was determined that zinc and cadmium ions affect weight indicators, survival and reproduction of experimental crayfish. Experimentally simulated concentrations of heavy metals on the example of zinc – 0.1 mg/l (10 MPC) and cadmium – 0.01 mg/l (2 MPC) allowed detecting the reaction of the excretory system of marbled crayfish. It is determined that under the influence of heavy metal ions the area of glandulocytes cells decreases by 10.4–14.8%. Also, there is a decrease in the cellular nucleus, thus, under the influence of zinc, the nucleus of the secretory cells was 23.6% smaller, and under the influence of cadmium by 17.5%. To study the influence of zinc and cadmium on the glandular cells of the green gland of marbled crayfish, the index of nuclear-cytoplasmic ratio (NCR) was used. The indicator of nuclear-cytoplasmic ratio allows estimating the level of metabolism and detecting the manifestation of compensatory reactions of the organism of experimental crayfish. The value of NCR in the experiment and control was not statistically different and ranged from 0.29 to 0.31 units. This indicates an interproportional reduction in both the cytoplasm of the cells of the green gland and their nuclei, caused by heavy metals exposure. The negative influence of heavy metals on the histostructure of hepatopancreas of marbled crayfish was determined; significant changes in the structure of tissue were noted, heavy metals influenced the shape of the hepatopancerase lobes and the size of the lumen. The worst histological picture of cells of experimental tissues and organs of marbled crayfish was observed in individuals exposed to cadmium ions due to the toxicological effects of this heavy metal. Investigation of the histological structure of tissues and organs of marbled crayfish will allow the development of measures for the determination of biomarkers for the bioindication of the aquatic environment using freshwater crayfish. The results of such studies have an important fundamental and applied significance for understanding the mechanisms of adaptation of crustaceans to the conditions of toxicological burden on aquatic ecosystems.

Keywords: Procambarus fallax f. virginalis Martin et al., 2010 • marbled crayfish • heavy metals • glandulocytes • hepatopancreas

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