การชักนำเพศปลาช่อนทะเลให้เสถียรด้วยเทคนิคขยายรูเยื่อหุ้มเซลล์ด้วยสนามไฟฟ้า

Abstract

The present study proposes a novel technique of monosex-male reversal for the commercially important marine fish of Cobia (Rachycentron canadum) using transient square pulse-electric and androgen hormone dose. The eggs of R. canadum had a simple spherical shape (~1.29±0.02 mm. in diameter) which is smaller than that of freshwater fish. The critical age of 6-19 hpf (hour post fertilization) were induced in the external field with square wave pulses of us-duration and amplitude of 100-350 VDC (equivalent to 26.25-87.5 kV.m1). The suspending medium of electroporation (EPM) contained a poor conductive medium with a minimized concentration of the androgen hormone 17 a -Methyltestosterone (MT). Mannitol and Sucrose are the main osmotica with HEPES Buffer or PBS Buffer. Using the amplitude of 350 VDC of 3 square-wave pulses of 50 μs duration with the concentration of 1,500 - 5,000 μg.l1 MT could be made all-male sex reversal. Hatching rate varied from 35.7±1.8 to 89.3±1.2 % (n=700) with the maximum survival rate to 85.2±1.7 %. Experimentations were achievable at a commercial density ranging from 700-1,000 eggs/10ml for each induction. Nevertheless, we have not yet accurately determined the sex reversal rate since their sex will be stable only after they are 2-3 years old. This novel technique could reduce the MT dose down to a minimized value with a rapid throughput of only quarter-hour per batch of eggs and using only 10 ml lots of hormone containing medium.