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Studies on bacterial pathogens isolated from diseased torafugu ( T akifugu rubripes ) cultured in marine industrial recirculation aquaculture system in S handong P rovince, C hina
Author(s) -
Wu Fushun,
Tang Kaihao,
Yuan Meng,
Shi Xiaochong,
Shakeela Qismat,
Zhang XiaoHua
Publication year - 2015
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.12220
Subject(s) - biology , virulence , microbiology and biotechnology , aquaculture , vibrio harveyi , bacteria , vibrio , 16s ribosomal rna , edwardsiella tarda , vibrionaceae , fish <actinopterygii> , fishery , gene , genetics , biochemistry
In spring of 2011, an epidemic outbreak of torafugu with high mortality occurred in an aquafarm with marine industrial recirculation aquaculture system ( MIRAS ) in Y antai, S handong P rovince, C hina. The diseased fish showed anorexia, haemorrhaging and festering fin and skin and swelling internal organs. Forty‐five dominant bacterial isolates were obtained from the diseased fish, and were found to belong to 12 species according to 16S r RNA gene sequences. One strain from each species was selected to test the pathogenicity, and five strains were showed to be virulent to zebrafish. Whereas E nterovibrio nigricans Fr42 was highly virulent with the LD 50 of 7.8 × 10 4 CFU g −1 , P hotobacterium swingsii Fr23, V ibrio owensii Fr40, V . harveyi Fr51 and V . rotiferianus Fr71 were moderately virulent with the LD 50 of 1.7 × 10 6 to 8.4 × 10 6 CFU g −1 . Both the bacteria and their extracellular products of the five strains were found to show phospholipase, caseinase, gelatinase, amylase and/or lipase activities. The production of N ‐acyl homoserine lactones ( AHL s) of the five strains was detected by three different AHL s biosensors, and three of them were found to produce AHL s by at least one kind of biosensor. This is the first study describing various opportunistic bacterial pathogens of fish cultured in MIRAS in C hina.