8-10 June 2016
Asia/Bangkok timezone

Enhancement of Electrical Sex Reversal Combined with Immersion Technique

Not scheduled
15m
Poster presentation Biological Physics

Speaker

Mr Sittichai Bunchuai (Biotechnology of Electromechanics Research Unit, Science of Physics, Faculty of Technology and Environment, Prince of Songkla University, Kathu, Phuket 83120, Thailand)

Description

The present study proposes an alternative technique of sex reversal for Nile tilapia (Oreochromis niloticus L.) to enhance all-male yield using transient pulse-electric fields combined with immersion technique. Tilapia’s eggs obtained from our parent breeding stocks were selected as the egg-stage development during segmentation-pharyngula (2-3dpf) (day post fertilization) for electrical inductions with the optimized electric field strengths of 87.50 kVm-1generated between narrow plate electrodes. Before induction, eggs were carefully washed and re-suspended in the special electroporation medium (EPM) (to be patent) prepared using HEPES buffer with various micro-concentrations of the androgen hormone of 17alpha-methyltestosterone (MT) of 500-1,000-1,500-10,000 µg.l-1 MT. All experiments had been performed at room temperature. It was found that tilapia’s eggs suspended in EPM with the ratio of 100 eggs/500 ml EPM had the critical tolerance limit at 10,000 µg.l-1 MT for the maximum duration of 24 hrs with hatching rates of 91.00%±2.65%, 79.33%±6.11%, 90.33%±2.08% and 81.67%±12.42% (P>0.05), respectively. Increasing MT concentrations shifted survival rates of tilapia to the lower values as 83.33%±3.06%, 73.00%±7.00%, 79.33%±3.51% and 57.00%±1.41% (P<0.01), respectively. The optimized electrical parameters used for the present study were constrained at the induced voltage of 375 VDC, 5 square wave pulses, 50 µs pulse durations with 1:1 mark-space ratio. We achieved to enhance all-male sex reversal rates of tilapia eggs combined with the immersion technique at 89.23%%±1.16%. By comparison to experiments of 1,500 µg.l-1 MT without immersion, all-male sex reversal rate had a lower value as 81.25% with hatching of 87.70%±15.13% (mean ± SD) and survival rate of 73.04%%±6.15% (mean ± SD).

Primary author

Prof. Sakshin Bunthawin (Biotechnology of Electromechanics Research Unit, Science of Physics, Faculty of Technology and Environment, Prince of Songkla University, Kathu, Phuket 83120, Thailand)

Co-author

Mr Sittichai Bunchuai (Biotechnology of Electromechanics Research Unit, Science of Physics, Faculty of Technology and Environment, Prince of Songkla University, Kathu, Phuket 83120, Thailand)

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