The shrimp gut is a dense and diverse ecosystem containing a collection of bacteria, archaea, viruses, and eukaryotic microorganisms, collectively termed the gut microbiota.

Several genetic and environmental factors shape the composition of the gut microbiota.

The gut microbiota also protects the shrimp against invasion of pathogens by occupying all available niches in the gut and producing inhibitory compounds preventing the colonization of the gut by these and other microorganisms

Phages were first discovered in 1915 by Twort and independently rediscovered and named in 1917 by d’Herelle, who named them after their lethal mode of action on bacteria (bacteriophage means “bacteria eater”)

During infection a phage attaches to a bacterium and inserts its genetic material into the cell. After that a phage usually follows one of two life cycles, lytic (virulent) or lysogenic (temperate). Lytic phages take over the machinery of the cell to make phage components. They then destroy, or lyse, the cell, releasing new phage particles.

With the recent and dramatic increase in antibiotic resistance, phages have returned to the spotlight as a promising therapeutic tool.

Phages replicate mostly through the lytic or lysogenic replication cycles, which have been extensively described. In brief, the lytic cycle is characterized by the direct production of new phages after infection of a bacterial cell, causing bacterial cell death