Oral administration of egg yolk immunoglobulin (IgY) in Penaeus vannamei to combat against VpAHPND infections.

Acute hepatopancreatic necrosis disease (AHPND), caused by the toxin-producing Vibrio sp., has become a serious threat to shrimp aquaculture. Egg yolk immunoglobulin(IgY) has the advantage of low cost and good protection in the treatment of diseases caused by specific pathogens in crustaceans. This study evaluated the protective effect of IgY against AHPND infection in Penaeus vannamei. IgY was isolated from eggs laid by hens immunized with recombinant PirAB toxin, which prepared with the PirAB gene as the target gene. Freeze-dried egg powders with anti-PirAB-IgY were mixed with basal diets at 20 % and 10 % concentrations and IgY from non-immunized hen (control-IgY) was mixed with basal diets at 20 % concentrations and used to prefeed shrimp 3 days before the bacterial challenge test. Survival rates of the challenged shrimp fed the anti-PirAB-IgY(20 %), anti-PirAB-IgY(10 %), and control-IgY diets were 70 %, 50 % and 13 %, respectively. The parameters including β-1,3-d-glucan-binding protein and Heat shock proteins 70 (Hsp70) had increased in the experimental groups fed with anti-PirAB-IgY compared with the positive control group, and the expression levels of crustin were significantly(P < 0.05) higher in the positive control group than in the other groups. This study provides an effective prophylactic method against AHPND infection in shrimp.