Pseudomonas alcaligenes infection and mortality in cultured Chinese sturgeon, Acipenser sinensis

Abstract

Abstract Chinese sturgeon (Acipenser sinensis) is a rare and endangered species, and also an important resource for the sturgeon aquaculture industry in China. Recently, a fatal bacterial disease occurred in farmed Chinese sturgeon. The clinical signs of the diseased fish were systemic blood loss and anemia. The gills were very pale with swollen and hemorrhagic gill filaments. Discrete blood spots were apparent in the oral cavity. Small petechial hemorrhages were present in pale livers and the digestive tract. Hemorrhages were also present in the kidney and gonad. The spleen was red and swollen. Additionally, a small amount of clear ascites fluid was present in the body cavity. A bacterial pathogen was isolated from the internal organs of diseased fish and subsequently identified as Pseudomonas alcaligenes by morphology, biochemical testing and phylogenetic analysis of the 16S rDNA. Experimental infection in healthy hybrid sturgeon confirmed the pathogenicity of the bacterial isolate. The results of this study represent the first isolation and identification of Pseudomonas alcaligenes in cultured Chinese sturgeon in China and provide a foundation for the diagnosis, prevention and treatment of this new disease. Statement of relevance The authors declare that there is no conflict of interests regarding the publication of this paper.