The influence of cadmium on Prussian carp oocyte maturation, development of eggs and hatching

Abstract

The influence of cadmium (Cd) on the last stage of Prussian carp (Carassius auratus gibelio B.) oocyte maturation and embryonic development was investigated. The (postvitellogenic) oocytes were incubated with carp pituitary homogenate (Chh), 17α,20β-dihydroxy-4-pregnen-3-one (17α,20βOH-P) and Cd at the concentrations of 20, 100 and 200μM. Cd was found to stimulate spontaneous oocyte maturation, however it inhibited Chh-stimulated maturation. Cd had no influence on the effects of 17α,20βOH-P (MIS - maturation inducing steroid). It seems that the action of Cd on the last stage of oocyte maturation takes place before the MIS production. In an in vivo study Prussian carp eggs were incubated in the water containing Cd at the concentrations of 0, 0.01, 0.1, 1 or 10 mg/l. There were no differences between the final numbers of hatched larvae in the respective groups, however Cd at the highest concentration accelerated hatching and increased the number of deformed larvae. These results suggest that Prussian carp eggs are very resistant to waterborne Cd.

Keywords

• heavy metals
• oocyte maturation
• steroid hormones
• embryonic development
• hatching enzyme