Lactococcus lactis subsp. lactis infection in Bester sturgeon, a cultured hybrid of Huso huso × Acipenser ruthenus, in Taiwan.

摘要: Abstract Approximately 5300 hybrid sturgeons with an average body weight of 600–800 g were farmed in 3 round tankers measuring 3 m diameter each containing 28,000 L aerated groundwater. According to the owner’s description, diseased fish had anorexia, pale color, and reddish spots on abdomen. The morbidity lethality rates this outbreak about 70% (3706/5300) 100% (3706/3706), respectively. clinical examination revealed enteritis, enlarged abdomen, rapid respiration rate. gross findings a volume 4 mL ascites. histopathological showed multiple massive, hemorrhagic or coagulative necrotic foci liver spleen. Furthermore, there was diffuse infiltration glycogen hepatic cells, few polymorphonuclear mononuclear leucocytes observed surrounding Some bacterial clumps noted around foci. We also that moderate severe, acute, multifocal, necrosis renal parenchyma, some present beneath margin kidney. Additionally, found pancreas. Results microbiologic examinations, including biochemical characteristics, PCR amplification 16S rRNA gene, sequencing comparison, phylogenetic analysis, pathogen infection Lactococcus lactis subsp. , based results antimicrobial agent sensitivity test bacterium only sensitive ampicillin florfenicol. vivo experimental infections tilapia 1 × 10 8 9  CFU/mL our isolate caused death all LD 50 values ranged from 10 2 5  CFU/mL. To best authors’ knowledge, is first reported case sturgeon.