PMID- 37372044 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20230701 IS - 2079-7737 (Print) IS - 2079-7737 (Electronic) IS - 2079-7737 (Linking) VI - 12 IP - 6 DP - 2023 May 23 TI - Identification and Characterization of Infectious Pathogens Associated with Mass Mortalities of Pacific Oyster (Crassostrea gigas) Cultured in Northern China. LID - 10.3390/biology12060759 [doi] LID - 759 AB - The Pacific oyster (Crassostrea gigas) aquaculture industry increased rapidly in China with the introduction and promotion of triploid oysters in recent years. Mass mortalities affecting different life stages of Pacific oysters emerged periodically in several important production areas of Northern China. During 2020 and 2021, we conducted a passive two-year investigation of infectious pathogens linked to mass mortality. Ostreid herpesvirus-1 (OsHV-1) was detected to be associated with mass mortalities of hatchery larvae, but not juveniles and adults in the open sea. Protozoan parasites, such as Marteilia spp., Perkinsus spp. and Bonamia spp. were not detected. Bacterial isolation and identification revealed that Vibrio natriegens and Vibrio alginolyticus were the most frequently (9 out of 13) identified two dominant bacteria associated with mass mortalities. Pseudoalteromonas spp. was identified as the dominant bacteria in three mortality events that occurred during the cold season. Further bacteriological analysis was conducted on two representative isolates of V. natriegens and V. alginolyticus, designated as CgA1-1 and CgA1-2. Multisequence analysis (MLSA) showed that CgA1-1 and CgA1-2 were closely related to each other and nested within the Harveyi clade. Bacteriological investigation revealed faster growth, and more remarkable haemolytic activity and siderophore production capacity at 25 degrees C than at 15 degrees C for both CgA1-1 and CgA1-2. The accumulative mortalities of experimental immersion infections were also higher at 25 degrees C (90% and 63.33%) than at 15 degrees C (43.33% and 33.33%) using both CgA1-1 and CgA1-2, respectively. Similar clinical and pathological features were identified in samples collected during both naturally and experimentally occurring mortalities, such as thin visceral mass, discolouration, and connective tissue and digestive tube lesions. The results presented here highlight the potential risk of OsHV-1 to hatchery production of larvae, and the pathogenic role of V. natriegens and V. alginolyticus during mass mortalities of all life stages of Pacific oysters in Northern China. FAU - Zhang, Xiang AU - Zhang X AD - Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China. FAU - Huang, Bo-Wen AU - Huang BW AD - Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China. FAU - Zheng, Yu-Dong AU - Zheng YD AD - Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China. FAU - Xin, Lu-Sheng AU - Xin LS AUID- ORCID: 0000-0002-4685-1076 AD - Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China. AD - Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China. FAU - Chen, Wen-Bo AU - Chen WB AD - Dalian Modern Agricultural Production Development Service Center, Dalian 116023, China. FAU - Yu, Tao AU - Yu T AD - Changdao Enhancement and Experiment Station, Chinese Academy of Fishery Sciences, Yantai 265800, China. FAU - Li, Chen AU - Li C AUID- ORCID: 0000-0002-2862-5702 AD - Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China. AD - Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China. FAU - Wang, Chong-Ming AU - Wang CM AUID- ORCID: 0000-0002-5517-9453 AD - Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China. AD - Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China. FAU - Bai, Chang-Ming AU - Bai CM AUID- ORCID: 0000-0001-5476-2455 AD - Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China. AD - Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China. LA - eng GR - 32073014/National Natural Science Foundation of China/ GR - cars-49/The earmarked fund for CARS/ PT - Journal Article DEP - 20230523 PL - Switzerland TA - Biology (Basel) JT - Biology JID - 101587988 PMC - PMC10295669 OTO - NOTNLM OT - OsHV-1 OT - Vibrio alginolyticus OT - Vibrio natriegens OT - histopathology OT - pathogenicity COIS- The authors declare no conflict of interest. EDAT- 2023/06/28 06:42 MHDA- 2023/06/28 06:43 PMCR- 2023/05/23 CRDT- 2023/06/28 01:10 PHST- 2023/03/31 00:00 [received] PHST- 2023/05/10 00:00 [revised] PHST- 2023/05/19 00:00 [accepted] PHST- 2023/06/28 06:43 [medline] PHST- 2023/06/28 06:42 [pubmed] PHST- 2023/06/28 01:10 [entrez] PHST- 2023/05/23 00:00 [pmc-release] AID - biology12060759 [pii] AID - biology-12-00759 [pii] AID - 10.3390/biology12060759 [doi] PST - epublish SO - Biology (Basel). 2023 May 23;12(6):759. doi: 10.3390/biology12060759.