The effect of temperature and heavy metals on heart rate changes in common carp Cyprinus carpio L. and grass carp Ctenopharyngodon idella (Val.) during embryonic development

Abstract

The study was conducted on common carp and grass carp embryos and larvae developed under laboratory conditions, at various temperatures and in the presence of heavy metals (Cu 0.20-0.27 mg dm^-3, Pb 2.0-4.0 mg dm^-3, Cd 0.2 mg dm^-3). Heart rate was measured at various developmental stages and was observed to increase along with fish development in all experimental groups. This may be explained by the increase in the metabolic rate of developing embryos. Development was faster at higher temperatures, and the heart rate was usually higher. The results of the present study confirm that heart rate is a reliable indicator of the metabolic rate of developing fish embryos.The embryos and larvae which were exposed to heavy metals had higher heart rates in comparison to those of the control group. This indicates that metal-induced stress caused an increase in metabolic rate. A decrease in heart rate during hatching was observed at non-optimum temperatures and was particularly pronounced in metal-exposed embryos; this indicates that the disturbances were related to the high sensitivity of the fish at this stage.

CORRESPONDING AUTHOR:

Barbara Jezierska, Akademia Podlaska, Wydział Rolniczy, Zakład Fizjologii Zwierząt, ul. Prusa 12, 08-110 Siedlce; Tel./Fax:+48 25 6431230; e-mail:jezbar@ap.siedlce.pl