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Zebrafish Embryo Disinfection with Povidone-Iodine: Evaluating an Alternative to Chlorine Bleach
Carolyn T Chang1, Jeffrey D Amack2, Christopher M Whipps1
11 Department of Environmental and Forest Biology, State University of New York, College of Environmental Science and Forestry , Syracuse, New York.
Abstract:
Mycobacteriosis is a common bacterial infection in laboratory zebrafish caused by several different species and strains of Mycobacterium, including both rapid and slow growers. One control measure used to prevent mycobacterial spread within and between facilities is surface disinfection of eggs. Recent studies have highlighted the effectiveness of povidone-iodine (PVPI) on preventing propagation of Mycobacterium spp. found in zebrafish colonies. We evaluated the effect of disinfection using 12.5-50 ppm PVPI (unbuffered and buffered) on zebrafish exposed at 6 or 24 h postfertilization (hpf) to determine if this treatment is suitable for use in research zebrafish. Our results show that 6 hpf embryos are less sensitive to treatment as fewer effects on mortality, developmental delay, and deformity were observed. We also found that buffered PVPI treatment results in a greater knockdown of Mycobacterium chelonae and Mycobacterium marinum, as well as results in decreased harmful effects on embryos. Treatments of shorter (2 min vs. 5 min) duration were also more effective at killing mycobacteria in addition to resulting in fewer effects on embryo health. In addition, we compared the efficacy of a rinsing regimen to rinsing and disinfecting. Based on the findings of this study, we recommend disinfecting embryos for 2 min with buffered PVPI at 12.5-25 ppm.
Insights
Buffered povidone-iodine (PVPI) effectively disinfects zebrafish embryos against mycobacteria, with shorter treatments and earlier application showing best results for research zebrafish. This method minimizes negative impacts on embryo development.
Area of Science:
- Aquatic animal health
- Microbiology
- Developmental toxicology
Background:
- Mycobacteriosis is a prevalent bacterial infection in laboratory zebrafish.
- Surface disinfection of zebrafish eggs is crucial for preventing pathogen spread.
- Povidone-iodine (PVPI) shows promise for controlling mycobacterial contamination.
Purpose of the Study:
- To evaluate the efficacy and safety of PVPI disinfection for zebrafish embryos.
- To determine optimal PVPI concentration, buffering, and treatment duration.
- To assess the impact of treatment timing (6 vs. 24 hours postfertilization).
Main Methods:
- Zebrafish embryos were exposed to varying concentrations (12.5-50 ppm) of buffered and unbuffered PVPI.
- Treatments were applied at 6 or 24 hours postfertilization (hpf) for 2 or 5 minutes.
- Efficacy against Mycobacterium chelonae and Mycobacterium marinum was assessed.
- Embryo mortality, developmental delay, and deformity were monitored.
Main Results:
- Zebrafish embryos at 6 hpf were less sensitive to PVPI treatment.
- Buffered PVPI demonstrated superior reduction of Mycobacterium spp. and fewer adverse effects on embryos.
- Shorter treatment durations (2 min) were more effective in killing bacteria and preserving embryo health.
- Rinsing plus disinfecting was more effective than rinsing alone.
Conclusions:
- Disinfecting zebrafish embryos with buffered PVPI at 12.5-25 ppm for 2 minutes is recommended.
- This protocol effectively controls mycobacteria while minimizing negative impacts on embryo development.
- Optimized disinfection protocols are essential for maintaining healthy research zebrafish colonies.
