ВПЛИВ СУБЛЕТАЛЬНИХ КОНЦЕНТРАЦІЙ ІОНІВ КОБАЛЬТУ (ІІ) НА ГЕМАТОЛОГІЧНІ ПОКАЗНИКИ В ОРГАНІЗМІ ПРІСНОВОДНИХ РИБ

The study examined changes in selected biochemical indicators (glucose, lactate, pyruvate levels, and lactate dehydrogenase activity) in the blood of crucian carp (Carassius gibelio Bloch) and pike (Esox lucius L.) exposed to 0.1 and 0.25 mg/dm³ of Co²⁺ ions in water. The results demonstrated that changes in the hematological parameters of fish are species-specific and depend on the concentration of metal ions in the aquatic environment. Despite exposure to sublethal concentrations of cobalt ions, the metal content in the blood of both fish species remained unchanged; however, in crucian carp, it was an order of magnitude lower than in pike. An increase in glucose concentration was observed in both species at both cobalt concentrations. Lactate levels in crucian carp increased under 0.1 mg/dm³ exposure, whereas in pike, they rose at 0.25 mg/dm³. Pyruvate concentration in crucian carp increased at 0.25 mg/dm³, whereas in pike, it decreased proportionally to the cobalt concentration in water. A positive correlation was observed between the lactate/pyruvate ratio and lactate dehydrogenase activity in the blood of both species at elevated cobalt concentrations. These findings suggest that in pike, at higher cobalt concentrations (0.25 mg/dm³), glycolytic processes play an increased role in the organism’s energy supply.