A potential application of shrimp antilipopolysaccharide factor in disease control in aquaculture

Antilipopolysaccharide factor isoform 3 from Penaeus monodon ( ALF P m 3) exhibits broad antimicrobial activities against various microbes, including bacteria, fungi and viruses, suggesting its potential use in disease control in shrimp aquaculture. Herein, the recombinant ALF P m 3 protein ( rALF P m 3) exhibited effective antibacterial action against Vibrio parahaemolyticus , the causative agent of the new severe emerging disease, early mortality syndrome ( EMS ) or acute hepatopancreatic necrosis disease ( AHPND ) at the minimum inhibitory concentration value of 1.25–5.00 μM. The morphological changes such as bleb formation and cell distortion of V. parahaemoluticus were introduced after rALF P m 3 treatment. Furthermore, to control V. parahaemoluticus infection, shrimp were treated with rALF P m 3 by immersion and reduction in the cumulative mortality of V. parahaemoluticus ‐infected Penaeus vannamei was observed. As a potential immunostimulant, the administration of dietary rALF P m 3 enhanced the transcript level of five immune‐related genes; ALF P m 3, haemocyte homoeostasis‐associated protein, phagocytosis‐activating protein, prophenoloxidase‐activating enzyme 1 and cytosolic manganese superoxide dismutase. In addition, dietary rALF P m 3 increased the shrimp survival after white spot syndrome virus ( WSSV ) injection by >35% compared to the 0% survival for the control group. Taken together, these results indicate the potential use of dietary rALF P m 3 as immunostimulant in controlling AHPND and WSSV infections in shrimp aquaculture.