Effects of chloramphenicol, florfenicol, and thiamphenicol on growth of algae Chlorella pyrenoidosa, Isochrysis galbana, and Tetraselmis chui

This study investigated the growth inhibition effects of three phenicol antibiotics on microalgae used in aquaculture. Different dose levels of chloramphenicol (CAP), florfenicol (FF), and thiamphenicol (TAP) were added to cultures of one freshwater green alga, Chlorella pyrenoidosa, and two marine algae, Isochrysis galbana and Tetraselmis chui. For the two marine algae, FF showed higher toxicity levels (EC50, 1.3-8 mg l(-1)) than CAP (4-41 mg l(-1)) and TAP (38-158 mg l(-1)). CAP was more toxic to the freshwater algae (EC50, 14 mg l(-1)) than FF (215 mg l(-1)) and TAP (1283 mg l(-1)). TAP was the least toxic to the three algae, but maintained the highest stability during the test period. Among the tested algae, T. chui was the species most sensitive to the three antibiotics. This study demonstrates that all three phenicol antibiotics can inhibit growth of the three microalgae and should be carefully used in aquaculture.