Acute hepatopancreatic necrosis disease (AHPND), caused by marine bacteria Vibrio Parahaemolyticus, is a huge problem in shrimp farms. The V. parahaemolyticus infecting material is contained in a plasmid which encodes for the lethal toxins PirAB^Vp, whose primary target tissue is the hepatopancreas, causing sloughing of epithelial cells, necrosis, and massive hemocyte infiltration. To get a better understanding of the hepatopancreas response during AHPND, juvenile shrimp Litopenaeus vannamei were infected by immersion with V. parahaemolyticus. We performed transcriptomic mRNA sequencing of infected shrimp hepatopancreas, at 24 hours post-infection, to identify novel differentially expressed genes a total of 174,098 transcripts were examined of which 915 transcripts were found differentially expressed after comparative transcriptomic analysis: 442 up-regulated and 473 down-regulated transcripts. Gene Ontology term enrichment analysis for up-regulated transcripts includes metabolic process, regulation of programmed cell death, carbohydrate metabolic process, and biological adhesion, whereas for down-regulated transcripts include, microtubule-based process, cell activation, and chitin metabolic process. The analysis of protein- protein network between up and down-regulated genes indicates that the first gene interactions are connected to oxidation-processes and sarcomere organization. Additionally, protein-protein networks analysis identified 20-top highly connected hub nodes. Based on their immunological or metabolic function, ten candidate transcripts were selected to measure their mRNA relative expression levels in AHPND infected shrimp hepatopancreas by RT-qPCR. Our results indicate a close connection between the immune and metabolism systems during AHPND infection. Our RNA-Seq and RT-qPCR data provide the possible immunological and physiological scenario as well as the molecular pathways that take place in the shrimp hepatopancreas in response to an infectious disease.

This work was undertaken to assess the effects that different environmental conditions of tropical and temperate aquaculture sites have on growth, survival, and reproduction of diploid and triploid Pacific oyster Crassostrea gigas. Diploid and triploid oysters were evaluated with the purpose of determining if the triploid condition results in any advantage on growth and survival that can be exploited for aquaculture of this species in tropical environments. The evaluations were performed by comparing three sites: two tropical sites in the Gulf of California and one temperate site in the Pacific Coast of the Baja California Peninsula, Mexico. When comparing tropical versus temperate sites, C. gigas growth and survival were less at the tropical sites regardless of ploidy. This can be attributed to environmental conditions, that is, high temperatures causing low productivity, in addition to an earlier-onset and sustained reproductive condition in the tropical sites when compared with the temperate s...