Antimicrobial photodynamic therapy (aPDT) uses light-specific wavelengths and nontoxic photosensitisers to eradicate target microbial cells. Bivalve hatchery systems are challenged with bacterial contamination of microalgae feed, which can be detrimental to all production life stages. The objectives of this study were to investigate the antimicrobial potential of blue LED and red laser aPDTs in a marine environment. The bacteria Vibrio spp. were targeted, as they have been associated with significant Pacific oyster Crassostrea gigas mortalities worldwide. The compartments tested were (a) microalgae feed (Tetraselmis sp., Isochrysis sp. and Chaetoceros muelleri) and (b) tank seawater. C. gigas seed-fed light-treated and untreated microalgae for 8 weeks were also screened for Vibrio spp. Molecular diagnostics (PCR, qPCR and Sanger sequencing) were used. The aPDTs were deemed non-destructive to the microalgae. V. splendidus was detected exclusively in C. muelleri growth cultures. Tank seawater samples were positive for V. splendidus pre-treatment. A complete eradication of V. splendidus RNA (indicative of pathogen viability) was observed in seawater samples treated by aPDTs, while no V. splendidus DNA (pathogen may be viable or not) was observed in seawater samples treated by red laser and a 33% reduction occurred when treated with LED. Of significance, a reduction of V. splendidus DNA and RNA was observed in oysters fed the aPDT-treated microalgae versus those oysters fed the untreated diet. This pilot study indicates that there is the potential to use aPDT to treat against pathogenic bacteria, in particular Vibrio spp., in hatchery microalgal feed and tank water.

抗菌光动力疗法（aPDT）使用特定于光的波长和无毒的光敏剂来消灭目标微生物细胞。双壳类孵化场系统面临着微藻饲料细菌污染的挑战，这可能对所有生产生命周期都是有害的。这项研究的目的是研究在海洋环境中蓝色LED和红色激光aPDT的抗菌潜力。细菌弧菌。由于它们与全世界大量的太平洋牡蛎Crassostrea gigas死亡有关，因此成为攻击目标。测试隔室是（a）进料的微藻（四爿属，球等鞭金属和牟氏角毛藻）和（b）罐海水。C. gigas还筛选了种子饲喂的光处理和未处理的微藻8周，以检出弧菌。使用了分子诊断（PCR，qPCR和Sanger测序）。认为aPDT对微藻无害。灿烂弧菌在专门检测C. muelleri成长的文化。储罐海水样品中的V. splendidus预处理呈阳性。的彻底根除灿烂弧菌通过aPDTs处理后的海水样品中观察到RNA（指示病原体活力），而没有灿烂弧菌DNA（病原体可以是活的或不）通过红色激光处理的海水样品和33％中观察到用LED处理时减少。重要的是，减少饲喂经aPDT处理的微藻类的牡蛎与未饲喂未经处理的日粮的牡蛎相比，可以看到脾脏弧菌的DNA和RNA。这项初步研究表明，有可能使用aPDT来治疗孵化场微藻饲料和储水箱中的病原细菌，尤其是弧菌。