Identification of immune genes in Penaeus vannamei stimulated with Ulva lactuca and infected with white spot syndrome virus

Abstract

White Spot Syndrome Virus (WSSV) is one of the main pathogens affecting shrimp culture. An effective strategy to reduce the impact of this infection is to strengthen the immune response in shrimp by administering immunostimulant compounds. In this work, the immune genes of Penaeus vannamei that are stimulated by the inclusion of Ulva lactuca flour. During 21 days, specimens of 7.25 ±0.87 g and 11.33 ±0.89 g were fed with commercially balanced feed and supplemented with 8% and 15% of U. lactuca flour. The shrimps were exposed, through Per os, to the WSSV. Survival was evaluated for a period of 10 days post-infection. In addition, in specimens of 11.33 ±89 g, the gene expression at 0 h and 72 h post-infection was evaluated by real-time PCR. Survival in both age groups varied between 25% and 37.5% in shrimps fed with supplemented diets, whereas the group that received only the commercial diet varied between 6.25% and 12.5%. Three genes were identified (Stylicin, Crustin, Mas) whose expression decreases (Tukey, P< 0.05) in the group of infected shrimps that were fed only with balanced feed, while the shrimps fed with balanced feed and U. lactuca flour are maintained in a similar way to healthy specimens. These results demonstrate that U. lactuca presents immunostimulant compounds that allow improving the survival of P. vannamei against WSSV infection.