Experimental studies on the effect of cadmium chloride, zinc acetate, their mixture and the mitigation with vitamin C supplementation on hatchability, size and quality of newly hatched larvae of common carp, Cyprinus carpio

The present results show that the fertilization and hatching rates, as well as the development of the embryos of common carp are adversely affected by heavy metal pollution. The degree of this effect depends on the duration and the concentration of the heavy metal used. Malformation of the yolk sac and curvature in the abdominal region were also observed throughout this study. No statistical difference was recorded between the polluted group which was supplemented with vitamin C (300 mg/kg of dry feed), and the control group (P < 0.05). The newly hatched larvae showed severe body malformation, and they were not able to swim or feed. Other organs such as the kidneys and livers were also affected. The most important changes in the kidneys of common carp were glomerular expansion and the reduction of Bowman’s space. No abnormalities or alterations were observed in the livers of the control fish. However, the main alterations were observed in the liver of treated fish with cadmium chloride that were either single or mixed with zinc acetate. The most important changes in the livers of common carp were hypertrophy nucleus and vacuolation in cytoplasm. Addition of vitamin C with dry feed showed an improvement in the tissues of livers and kidneys of polluted fish.