Survival and immune-related gene expression in Litopenaeus vannamei co-infected with WSSV and Vibrio parahaemolyticus

In the present study, survival and immune-related gene expression were investigated in atopenaeus vannamei co-infected with white spot syndrome virus (WSSV) and Vibrio parahaemolyticus by ingestion and immersion, respectively.The expression of five immune-related genes (translationally controlled tumor protein ITCTPI, toll receptor [LvTolll, penaeidin4, crustin, and lysozyme) in hemocytes of experimental shrimp was measured by realtime quantitative PCR. Shrimp infected first with V. parahaemolyticus and then with WSSV showed a mortality of 46.66 +/- 0.88%. Shrimp infected first with WSSV and then with V. parahaemolytiais showed a mortality of 45.00 +/- 1.53%. Shrimp infected with WSSV and V. parahaemolyticus at the same time showed a mortality of 55.00 +/- 2.08%. Gene expression of LvToll, crustin, and lysozyme was upregulated whereas gene expression of TCTP and penaeidin4 was downregulated. Under the present experimental conditions and infection routes, V. pm-ahaernolyticus was the main responsible for the mortality of cultured white shrimp. Regarding immune response, significant changes were found in gene expression in hemocytes of L vannamei during the time-course of a successful immune response to pathogens V. parahaemolyticus and WSSV. Statement of relevance: Bacterial and viral co-infection in white shrimp culture. (C) 2016 Elsevier B.V. All rights reserved.