Growth acceleration of Nile tilapia at 21 to 31 weeks of age with plasma-treated air-supplied water

Abstract

This study aimed to develop a technique to accelerate fish growth without using genetic modification or genome editing. We have prepared a reactor with four pairs of opposed electrodes and a high-voltage power supply for the discharge. An arc discharge generates a plasma-treated gas in the reactor. Plasma-treated gas containing active species such as nitric oxide (NO) was generated via an arc discharge in the atmosphere and inserted into an aquarium containing Nile tilapia. No ozone was detected in the plasma-treated gas. Plasma treatment gas was supplied to the 20 L tank at a flow rate of 10 L per minute for varying supply times. The supply duration of plasma-treated air to the water tank was 0.5, 2, 5, and 15 min. Tanks were prepared for each of these four conditions, and gas was supplied daily at the same time. We observed that on supplying plasma-treated gas to tilapia from the 16th week of age for 5 min daily, the average length of the fish at 31 weeks of age was ∼1.5 times longer than that of the control fish. All other supply time conditions were also found to grow acceleration over the control. In the 15-minute supply time condition, individual differences in body length were more significant. A sample had more growth suppression than controls. In other words, the results suggest that an excess supply of active species can cause growth inhibition. These results suggest that an optimal supply of plasma-treated gas has a growth-promoting effect on fish.

Key policy highlights

• The fish growth was accelerated by supplying plasma-treated air to the tank.

• The amount of ozone in the plasma-treated air was below the detection limit, and a large amount of RNS, such as nitric oxide, was generated.

• After an experimental period of 16 to 31 weeks, the average length of fish in the most significant growth condition was 1.5 times that of the control fish.

Keywords:

• Growth acceleration of fish
• atmospheric pressure plasma
• nitric oxide

Acknowledgments

This work was supported by Ehime University South Ehime Fisheries Research Center. This work was supported by Ehime University Research Unit.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Part of this work was supported by a project, 22712871, subsidized by the New Energy and Industrial Technology Development Organization (NEDO). Part of this work was funded by consigned research fund from Shikoku Electric Power Company, Incorporated.