I+R+D

Plasma technology has the potential to disinfect water in the rearing of tilapia larvae

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By Milthon Lujan

grupo tilapias sanipes

One of the main concerns in the aquaculture industry is the outbreak of diseases in fish farms, which leads to economic losses and threatens food security. Traditionally, antibiotics and disinfectants have been used to combat this problem. However, these chemicals can contaminate water and fish, harming the environment and potentially reaching consumers.

Fortunately, innovative solutions are emerging. Biotherapeutic approaches, such as probiotics, are promising but require specialized handling. This is where plasma technology steps in and changes the game.

Scientists at the Suranaree University of Technology applied dielectric barrier discharge (DBD) plasma to reduce the microbial population in the water of a recirculating aquaculture system (RAS) for rearing Nile tilapia larvae. This plasma produces reactive species that effectively kill bacteria, viruses, and fungi.

The Power of Plasma: Chemical-Free Disinfection

Plasma, generated by electricity, transforms gas into a unique state of matter. This “activated” state creates highly reactive particles that can be harnessed for various applications, including water disinfection.

One method, called dielectric barrier discharge (DBD) plasma, is particularly attractive. It operates at atmospheric pressure and low temperatures, making it simple and versatile. When applied to water, DBD plasma produces reactive species such as ions, radicals, and ultraviolet light. These “attackers” target microorganisms, damaging and eliminating their cell walls.

Plasma Activated Water (PAW): Safe and Effective

The resulting solution, PAW, offers several advantages:

  • Chemical-Free: Unlike traditional disinfectants, PAW leaves no harmful residues.
  • Broad-Spectrum Effectiveness: PAW targets various bacteria, viruses, and fungi.
  • Low Concentration: PAW works effectively even at low doses.
  • Environmentally Friendly: PAW naturally decomposes, minimizing environmental impact.
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Research: Optimizing PAW for Aquaculture

Research focuses on designing and optimizing a PAW system for tilapia hatcheries within recirculating aquaculture systems (RAS). Researchers evaluated the efficacy of PAW in reducing waterborne microorganisms while ensuring it does not harm the fish.

Researchers then established Nile tilapia larvae cultures in the RAS and introduced a mix of bacteria (including potentially harmful strains) to assess the efficacy of PAW against a realistic challenge. Three groups were compared:

  • Control: No PAW or antibiotics
  • PAW Treatment
  • Antibiotic Treatment

Key Findings

After 672 hours, both the PAW and antibiotic treatments significantly reduced bacterial populations in the water compared to the control. Additionally, both treatments showed a substantial decrease in bacteria within the fry.

The initial findings are encouraging: PAW treatment is promising in controlling bacteria without affecting the survival, growth, or composition of tilapia larvae.

PAW: Safe and Effective for Long-Term Aquaculture

A follow-up experiment with similar treatment groups confirmed the efficacy of PAW in reducing waterborne and whole-body bacteria in tilapia fry. Importantly, this study found no negative impacts on fish growth or body composition (moisture, protein, fat, and ash) across all groups. This suggests that PAW offers a safe and long-term solution for disease control in tilapia aquaculture.

PAW: A Sustainable Future for Aquaculture?

These findings suggest that PAW technology offers a safe and efficient alternative to antibiotics for controlling bacteria in tilapia larvae culture. Here’s why PAW is a promising approach for the future of aquaculture:

  • Reduced Antibiotic Dependence: PAW can minimize the need for antibiotics in aquaculture, promoting safer fish for consumers and reducing the risk of antibiotic resistance in bacteria.
  • Environmentally Friendly: PAW leaves no harmful residues, making it an eco-friendly solution for maintaining water quality in aquaculture systems.
  • Effective Disinfection: PAW effectively combats various bacteria, including pathogens, promoting the health of young fish.
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Conclusion

Plasma technology, through PAW, represents a significant advancement for rearing tilapia larvae; however, more research is needed to explore its applications in different fish species and aquaculture environments.

By ensuring clean water and healthy fish, PAW can contribute to a more sustainable and secure aquaculture industry, benefiting both fish farmers and consumers. It is important to note that plasma-activated water has already been tested on shrimp to protect them from diseases.

Contact
S. Boonanuntanasarn
School of Animal Technology and Innovation, Institute of Agricultural Technology, Suranaree University of Technology
111 University Avenue, Muang, Nakhon Ratchasima 30000, Thailand
Email: surinton@sut.ac.th

Reference
Thongsopa, C., Santalunai, S., Thosdeekoraphat, T., Kumkhong, S., Nakharuthai, C., Pasomboon, P., & Boonanuntanasarn, S. (2024). Optimisation of plasma-activated water: Plasma DBD technology and application in recirculating aquaculture system for Nile tilapia larval culture. Aquaculture, 741049. https://doi.org/10.1016/j.aquaculture.2024.741049