Análise histológica e molecular de agentes etiológicos causadores de enfermidades em camarões marinhos Litopenaeus vannamei cultivados em duas fazendas com sistema semi-intesivo no sul de Honduras

Abstract

The culture of white shrimp continues to grow faster than other species in aquaculture, with most shrimps being produced in Asia. Production of marine shrimp in Latin America countries such as Brazil, Honduras, Mexico and Ecuador are relevant in the economic context of aquaculture. The productions in Honduras generate an annual average of approximately $216 million exportable. The incidence of infectious diseases in aquaculture is one of the factors that most affect the sustainability of the industry. In 2017 Honduras reported the presence of four to nine obligatory reporting diseases: Necrotizing Hepatopancreatitis (NHP), Infection with Infectious Hypodermal and Hematopoietic Necrosis (IHHNV), Infection with Taura Syndrome Virus (TSV) and finally Infection with White Spot Syndrome Virus (WSSV). It was drawn as a general objective: to identify and characterize molecularly etiological agents of causing diseases in marine shrimp L. vannamei cultivated in Honduras, as well as to analyze histopathological shrimp tissues collected in Reserva de Vida Silvestre Los Delgaditos. In this study, the presence of the main diseases was determined by molecular analysis through conventional PCR and real-time PCR (qPCR), in addition to histological analysis to detect the presence of pathogen agents or characteristic damages of respective diseases in the cephalothorax tissues. Due to molecular analysis was identify presence of IHHNV, NHP (qPCR) and WSSV (conventional and qPCR) in Honduran originated tissues, which subsequently respective fragments of WSSV were sequenced, showing after phylogenetic analyses the presence of three haplotypes with a difference in nucleotide sequence when compared with isolates from India (MG702567.1) and South Korea (JX515788.1). Finally, qPCR showed that there was a coinfection between IHHNV and WSSV in two of twenty-seven tissues and three of twenty-seven tissues were coinfected with IHHNV and NHP in Honduran shrimp tissues. Nevertheless, when compared with histological analysis, the presence of damage characteristic of systemic Vibriosis and atrophic of the hepatopancreas in shrimp analyzed was detected, furthermore to the presence of spheroids in the lymphoid organ and multifocal necrosis gills and presence of gregarines in the midgut were documented. The importance of the development of this dissertation resulted in the molecular characterization of the first nucleotide sequences respective to the WSSV lineages present in Honduras, as well as the identification of viral and bacterial coinfections.