Cyanobacteria produce high levels of ergothioneine

Ergothioneine (ET) is a unique natural antioxidant. We have examined the origin of ET in zebrafish. There was virtually no ET, measured by LC–MS, in most tank vegetation (plant, green and red alga). However, ET was detected in a Phormidium sample, a cyanobacterium. In commercial fish feed preparations, ET content increased with the content of cyanobacteria Arthrospira platensis or Arthrospira maxima (Spirulina). High levels of ET (up to 0.8 mg...