Reducing Vibrio load in Artemia nauplii using antimicrobial photodynamic therapy: a promising strategy to reduce antibiotic application in shrimp larviculture.
Bottom Line: We propose antimicrobial photodynamic therapy (aPDT) as an alternative strategy to reduce the use of antibiotics in shrimp larviculture systems.This resulted in the death of >50% of the cells within the first 10 min of exposure and the 50% reduction in the cell wall integrity after 30 min could be attributed to the destruction of outer membrane protein of V. harveyi by reactive oxygen intermediates produced during the photosensitization.In conclusion, the study demonstrated that aPDT with its rapid action and as yet unreported resistance development possibilities could be a propitious strategy to reduce the use of antibiotics in shrimp larviculture systems and thereby, avoid their hazardous effects on human health and the ecosystem at large.
Affiliation: National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Kochi 682016, India.Show MeSH
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Mentions: We first assessed the toxicity of RB with or without photosensitization in Artemia nauplii. The freshly hatched nauplii were exposed to different concentrations of RB for 180 min in the presence and absence of light. The nauplii were considered dead if no appendage movement was observed and survival was calculated from the average number of live nauplii per total count. We found that RB at all concentrations, in the presence or absence of light is not toxic to Artemia nauplii (Fig. 5). Separately, when the nauplii were exposed to the pathogen, treated with RB and photosensitized, total bacterial population significantly reduced, especially those of vibrios (Fig. 6). It was observed that, 78.9% of the total heterotrophic bacterial population was reduced in Artemia nauplii exposed to aPDT. More interestingly, 91.2% of the Vibrio populations were removed from Artemia nauplii on aPDT. This indicated that aPDT was effective in killing the pathogen under in vivo conditions as well, without deleterious effects on Artemia nauplii.
Affiliation: National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Kochi 682016, India.