Biocontrol of pathogens in shrimp hatcheries using bacteriophages

Microflora associated with larval stages of shrimp could affect the health and development of the larvae. Some bacteria such as luminous Vibrio harveyi cause serious mortalities. Consequent to the ban on use of most antibiotics in aquaculture, there is a need for alternate technologies for control of bacterial pathogens. Bacteriophages have a potential to control bacterial pathogens. This paper reports isolation of lytic bacteriophages against V. harveyi. Four bacteriophages were isolated, three from oyster tissue and one from shrimp hatchery water. The bacteriophages lysed 55–70% of the 100 V. harveyi isolates tested. Two bacteriophages subjected to further study were found to belong to family Siphoviridae and were effective in reducing V. harveyi population in biofilm formed on high density polyethylene (HDPE) surface. In hatchery trials, bacteriophage treatment at 2 × 106 pfu ml− 1 level resulted in over 85% survival of Penaeus monodon larvae suggesting that bacteriophage therapy would be an effective alternative to antibiotics in shrimp hatcheries.