Influence of long-term exposure to lead on its accumulation and elimination from tissues and on selected reproductive parameters in the Prussian carp (Carassius gibelio B.) in pond environment

The bioaccumulation of lead in selected tissues of Prussian carp kept in pond condition during 12 and 24 months of exposure to different doses (8, 13, 24, and 49 mg/kg) of this metal in feed and its elimination from tissues during the following 12-month depuration period was studied. Additionally gonadosomatic index and luteinizing hormone (LH) secretion, as the effect of exposure to Pb, were examined. The concentration of lead in all the studied tissues, except for the gonads, correlated positively with the metal concentration in the diet, and the maximum level was usually achieved after 3 months of the exposure. The highest levels of lead, i.e. 2.1 ± 0.14 mg/kg, were found in the posterior intestine in the 15th month of the exposure, followed by bones, scales and kidneys, in which the level of lead amounted to 1.8 ± 0.20, 1.22 ± 0.07, and 1.17 ± 0.17 mg/kg, respectively. The negative effect of chronic exposure to lead was manifested by a significantly higher spontaneous LH secretion in groups exposed to 24 and 49 mg/kg of lead and a higher LH secretion level 6 h after the stimulating secretion. After 12 months of exposure and 12 months of depuration, as well as after 24 months of exposure, the effects of lead on LH secretion were not observed. Environmental lead can be a potent endocrine disruptor, which may have an adverse impact on fish reproduction. Prussian carps become resistant to the negative effects of lead with age and their organisms cope by reaching a state of homeostasis.