Bacteriophage cocktails as an environmentally-friendly approach to prevent Vibrio parahaemolyticus and Vibrio harveyi infections in brine shrimp (Artemia franciscana) production

Vibrio parahaemolyticus and Vibrio harveyi are commonly associated with brine shrimp, where they proliferate at the time of hatching and colonize nauplius surfaces, becoming a potential risk to organisms feeding on them. Among the strategies to prevent their occurrence, the use of chemotherapeutic agents and disinfectants could be considered; however, these strategies have side effects on the quality of brine shrimp and the environment. As a consequence, the use of bacteriophages (phages) is gaining interest in aquaculture. In this study, we investigated the effect of phage therapy (single phages and cocktails) on hatching and survival of brine shrimp (Artemia franciscana) cysts and nauplii exposed to pathogenic strains of V. parahaemolyticus and V. harveyi. The results revealed that application of single phages enhanced significantly (p < 0.05) the hatching success and survival rate, even at low multiplicity of infection (MOI). Subsequently, these promising phages were mixed (cocktails) and administered to brine shrimp cysts and nauplii exposed to both pathogenic Vibrio species. The results also revealed an enhanced hatching success (100% in both cases) and survival rate (from 85 to 89%) in groups treated with phage cocktails, whereas control groups had a hatching success of around 50% and survival rate from 40 to 50%. Given this, phage cocktails offer an alternative to chemotherapeutic agents routinely used in brine shrimp production.