[Survival of amphibian embryos after continuous ultrasound treatment]

The influence of continuous ultrasound on the embryonic development of grass frog Rana temporaria has been investigated. Intact embryos at the blastula stage were treated by ultrasound of different frequency (0.88 and 2.64 MHz), intensity (0.05-1.0 W/cm2), and duration (1-15 min). The treatment with ultrasound of frequency 0.88 MHz and intensity 0.05 W/cm2 for 1-5 min tended to increase the proportion of normally developing embryos up to hatch (10-25% of control). Increasing the intensity of ultrasound (0.88 MHz) to 0.7-1.0 W/cm2 and the duration of its action to 5-15 min induced the death of almost all of treated embryos. No significant differences were found between the development of control embryos and embryos treated with ultrasound of middle intensity (0.2-0.7 W/cm2) for 1-5 min. The exposure of amphibian embryos to ultrasound of frequency 2.64 MHz and intensity 0.05-0.7 W/cm2 for 1-5 min did not change their survival. Increasing the intensity of ultrasound (2.64 MHz) to 1.0 W/cm2 and the duration of its action to 5 min decreased the number of normal developing embryos (by 35%).