Abstract
Striped catfish Pangasianodon hypophthalmus farmed in the Mekong Delta, Vietnam, is an important component of national aquaculture exports. However, bacterial diseases result in the decrease of striped catfish production efficiency and the most popular disease is white spots in the internal organs caused by Edwardsiella ictaluri. In this study, four phages specific to E. ictaluri, designated G1, G7, G8 and G9.2, were isolated from striped catfish liver samples and characterized. Morphological analysis indicates probable placement in the Corticoviridae or Tectiviridae family with a 46 – 48 nm icosahedral head and no tails. According to one-step growth curves, their latent period and burst size were 55 – 70 min and 28 – 160 PFU/cell. E. ictaluri was challenged in vitro in broth and was inactivated by single phage for 18 – 20 h. However, a phage cocktail of G7 + G8 was markedly effective in inactivation of the host cells for 45 h. The current study is the first report about success of phage cocktail to inactivate E. ictaluri, an infectious agent in striped catfish Pangasianodon hypophthalmus.
