Infection of farmed sub-adult semicircle angelfish, Pomacanthus semicirculatus in Taiwan caused by Photobacterium damselae subsp. piscicida

Abstract

The semicircle angelfish (Pomacanthus semicirculatus) is an extremely popular coral reef teleost. An outbreak occurred in Taiwan with 98% (53 out of 54) cumulative mortality within 10 days among the cultured sub-adult semicircle angelfish. The most significant gross pathological change was the enlargement of the spleen. Histopathologically, bacterial microcolonies were observed in the vascular blood of the gill and internal organs. The identification of micro-organisms isolated from internal organs was verified by multiplex PCR assay for Photobacterium damselae subsp. piscicida that gave the expected specific amplicon of 267 bp of the 16S rRNA sequence but no amplification of partial urease gene occurred. Additionally, partial sequence of the 16S rDNA gene of the isolate from the fish was also phylogenetically compared and produced 99.83% sequence identity with P. damselae subsp. piscicida (GenBank accession number KU245711). This investigation is the first published on P. damselae subsp. piscicida infection in farmed semicircle angelfish.