Screening of Vibrio harveyi bacteriophages for controlling luminous vibriosis in shrimp (Penaeus monodon) hatcheries

Six bacteriophages, which are specific to Vibrio harveyi as host, were detected from 67 samples of hatchery water and grow-out pond soil of black tiger shrimp (Penaeus monodon). The bacteriophages were screened for their effects on cell lysis of 35 pathogenic strains of V. harveyi. The drop method showed that two bacteriophages (Vh-Pg7 and Vh-Pg10) are the most effective in cell lysis activity. However, there were also unclear results on the growth inhibition of V. harveyi when the co-culturing method was employed. The results of virulence tests revealed that both phages have no negative impact on the intestinal bacterial flora and do not cause any mortality in the shrimp samples. When one of the phages was added to shrimp tanks to control V. harveyi infection during the rearing period from naupliar to postlarval shrimps, there was no significant difference (P≥0.05) in the survival rate of control shrimps, those treated with phage, and those treated with oxytetracycline groups.