Journal of Aquaculture Research & Development

Molecular cloning and expression analysis of arginase-1, arginase-2 and inducible nitric oxide synthase genes of pacu fish (Piaractus mesopotamicus) infected with Aeromonas dhakensis

3^rd International Conference on Aquaculture & Fisheries

September 29-October 01, 2016 London, UK

Mateus M Carriero, Gabriel S A Moreira, Antonio A M Maia and Flavio Henrique-Silva

University of São Paulo, Brazil
Federal University of São Carlos, Brazil

Posters & Accepted Abstracts: J Aquac Res Development

Abstract:

In this study, we performed an expression analysis of the Arg1, Arg2 and iNOS genes in the liver, head kidney and spleen of pacu (Piaractus mesopotamicus) in four periods post-infection in response to the experimental infection of the bacteria Aeromonas dhakensis. The strain used in the study was isolated and characterized by biochemical tests and identified as strain, which belongs to the genus Aeromonas. Further molecular analyses of the 16S rRNA, gyrB and rpoD genes showed that this strain belongs to the species A. dhakensis, which had never been reported in South America. Following the infection with A. dhakensis, the Arg1 gene expression levels were decreased in the head kidney 24 h post-infection and the Arg2 gene expression was reduced in the liver at 12 h and 24 h post-infection and increased in the spleen at 24 h and 48 h post-infection; the gene expression of iNOS was significantly higher in the spleen at 12 h, 24 h, and 48 h post-infection. The results showed that the Arg2 and iNOS genes were the most differently regulated in response to the A. dhakensis infection, indicating that they are involved in the initial immune response to bacterial infections in pacu. This is the first study that characterized and assessed the expression levels of the Arg1, Arg2 and iNOS genes in pacu in response to the infection of A. dhakensis, providing a valuable contribution for the understanding of the immune response mechanisms against bacterial pathogens in this important South American fish species.