Introduction of encysted metacercarial stephanostomum sp. in javanese ricefish (oryzias javanicus) and bacterial diversity of encysts from mangrove swamps of Trang Province, Thailand

Abstract

The genus Stephanostomum consists of digenean parasites that are found in many marine teleost fish. In this study, we aimed to describe the metacercarial cysts of Stephanostomum sp. in Javanese ricefish (Oryzias javanicus) collected from brackish water of mangrove swamps in Sikao District, Trang Province, Thailand. The morphology and tegumental histology of the worms were examined. Furthermore, molecular phylogenetic trees were established based on 16S, 12S, 18S and 28S ribosomal DNA (rDNA) sequences, including an analysis of the symbiotic bacteria of Stephanostomum cysts using a 16S rDNA pyrosequencing method. Partial rDNA sequences of Stephanostomum were highly matched to S. cf. cestillium for percentage of similar identity from the nucleotide database of GenBank. Proteobacteria and Firmicutes were dominant on parasitic cysts with their environments. Our results contribute to the understanding of Stephanostomum from the Andaman Sea of Thailand. © 2020, Prince of Songkla University. All rights reserved.