Parameters of the Histological Adaptation of Marmorkrebs Procambarus virginalis (Lyko, 2017) (Decapoda, Cambaridae) to Manganese, Nickel and Lead Ions Pollution

Manganese, lead and nickel are heavy metals, which are the priority fresh water toxic contaminants and relate to of the first danger class chemicals. Heavy metals cause functional disorders in the tissues and organs of hydrobionts, affecting their linear and weight indices, reproductive system, digestive and extraction organs. In the experiment on marbled crayfishProcambarus virginalis(Lyko, 2017) studied the long-term effects of various concentrations of heavy metal ions on the physiological state and histostructure of tissues and organs. According to the results of research, it was found that among the studied heavy metals nickel ions influenced the weight indexes and mortality of crustaceans the most negatively. The results of morphometric studies on marbled crayfish indicate no significant changes in the control group and experimental one, but heavy metals influenced the form of the hepatopancerase lobes and the size of the lumen of the gland. Research on adipocytes of the connective tissue showed a significant difference between the size of cells under the influence of heavy metals. Dimensions of adipocytes fluctuated in a wide range from 144 μm2to 537 μm2. In control group the adipocyte area was 406.96 μm2. Experimental studies of hemolymph showed that, under the influence of lead ions, a significant increase in 1.4 times was observed in the area of hemolymph cells; when manganese and nickel were added, moderate decrease was observed in cells. It was found that under the influence of nickel, the area of round hyalinocytes has reduced by 1.7 times.