The Effect of Heat Shock on the Embryonic Development of Tetraploid Clarias gariepinus

Abstract

African catfish Clarias gariepinus species have a lot of muscle includes a high concentration of mono- and polyunsaturated fatty acids, as well as a high concentration of linoleic acid, an important fatty acid. This research aims to evaluate the effect of heat shock on the formation of tetraploid African Catfish, Clarias gariepinus during embryonic development. Tetraploidization was induced, by a 2 minutes heat shock at 39°C, 40°C, and 41°C approximately 40 minutes after fertilization, each treatment was replicated three times and compared to the control (diploid eggs). The result indicated that the percentage of fertilization and embryonic development during the cleavage, blastula, and gastrula stages was similar in the 39°C, 40°C, and 41°C treatments and control. However, embryonic segmentation was observed earlier during heat shock treatment (39°C, 40°C, and 41°C) compared to the control treatment at 8:30 hours. Furthermore, during the segmentation stages, the 40°C treatment shows more advanced development of the first somite, tail appearance, and early movement embryo compared to other treatments (39°C and 41°C). At 22:30 hours, the 40°C treatment was recorded on an early hatched C. gariepinus larva with a fully developed heart, heartbeat, and blood circulation. The findings suggest that heat shock treatment can be used to produce tetraploid food fish with fast growth characteristics that can be applied in mass culture production.