Abstract
The resistance of common carp (Cyprinus carpio L.) eggs to hot and cold shock has been studied by measuring the survival rate during the course of an incubation at a constant temperature of 20 °C. When incubation was pursued in oxygen-saturated conditions, a 1-h-long thermal shock which occurred during the synchronous segmentation stage had no effect within the temperature range of 8–28 °C. At gastrula stage, this interval reached 0.3 °C and at the end of epiboly it reached 36 °C. With hypoxic incubation conditions, a 1-h postepibolic shock had no effect within the range of 1–36 °C. On the contrary, a 12 °C (or less) preblastulean cold shock or a 30 °C (or more) pregastrulean hot shock induced a significant loss of further resistance to hypoxy. An overoxygenation during the shock did not increase the embryonic resistance. During the synchronous segmentation, the sensitivity to cold shock varied occasionally, possibly in relation with the mitotic cycle. Sensitivity to thermal shock also depended on the gametes' fertility. The resistance to thermic shock was compared with the thermic profiles that are described to be optimum in laboratory conditions at constant temperature, or in natural conditions of development. Hypoxy or hyperoxy cannot be the determining factor in thermic-shock effects on carp eggs: several hypotheses were reviewed to explain the acquisition of an increasing resistance to the variation of the environmental temperature.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.