■由于多年来大黄鱼的高密度养殖,由细菌等病原体引起的疾病,病毒,和寄生虫经常发生在宁波,对大黄鱼湾养殖业的持续健康发展构成了巨大的威胁和挑战。为了解宁波地区大黄鱼养殖病害的发生情况,2023年通过定期采样对大黄鱼病进行了流行病学调查。
■从2023年4月至10月,每月在宁波各养殖区进行大黄鱼的常规采样。每一次,对具有明显临床症状的活的或垂死的大黄鱼进行采样,收集了55个大黄鱼。将样品保存在冰袋中,并运送到实验室进行病原体检测(包括细菌分离和鉴定,病毒鉴定,和寄生虫检测)。
■本研究共收集了55条临床症状明显的垂死大黄鱼,其中78.18%(43/55)被检测到由病原体感染引起的症状,而21.82%(12/55)没有发现病原体,被认为是繁殖擦伤,营养代谢紊乱,非常规病原体感染或其他原因。共分离出25株病原菌,主要是斑纹假单胞菌和哈维氏弧菌,占病原菌菌株的52%(13/25)和32%(8/25),分别。其中,哈维伊氏弧菌和链球菌。iniae共感染了一条鱼。此外,另外三种细菌菌株,包括诺卡氏菌,腐生葡萄球菌,和光细菌豆科植物亚种。是被隔离的。显微镜检查主要观察到两种寄生虫,隐虫虫和新吸虫。在病毒检测中,主要在大黄鱼中检测到红海的虹彩病毒(RSIV)。统计分析表明,在检出病原体的鱼类中,55.81%(24/43)有细菌感染,37.21%(16/43)有寄生虫感染,37.21%(16/43)有RSIV感染。其中,五种鱼的细菌和寄生虫混合感染,三个人混合感染了细菌和病毒,三个人感染了寄生虫和病毒,一个大黄鱼有混合感染病毒,细菌,和寄生虫。
■这些发现表明,这三种主要类型的疾病在宁波大黄鱼养殖区非常常见,意味着多种疾病混合感染的复杂性。
UNASSIGNED: Due to the high-density farming of Larimichthys crocea over the years, diseases caused by pathogens such as bacteria, viruses, and parasites frequently occur in Ningbo, posing a huge threat and challenge to the sustainable and healthy development of the L. crocea\'s bay farming industry. In order to understand the diseases occurrence in L. crocea farming in Ningbo area, an epidemiological investigation of L. crocea diseases was carried out through regular sampling in 2023.
UNASSIGNED: From April to October 2023, routine sampling of L. crocea was conducted monthly in various farming areas in Ningbo. Each time, live or dying L. crocea with obvious clinical symptoms were sampled, with a total number of 55 L. crocea collected. The samples were preserved in ice bags and transported to the laboratory for pathogen detection(including bacterial isolation and identification,virus identification, and parasites detection).
UNASSIGNED: A total of fifty-five fish dying L. crocea with obvious clinical symptoms were collected in this study, of which 78.18% (43/55) were detected with symptoms caused by pathogenic infection, while 21.82% (12/55) did not have identified pathogens, which were presumed to be breeding abrasions, nutritional metabolic disorders, unconventional pathogens infection or other reasons. A total of twenty-five pathogenic bacteria strains were isolated, which mainly were Pseudomonas plecoglossicida and Vibrio harveyi, accounting for 52% (13/25) and 32% (8/25) of the pathogenic bacteria strains, respectively. Among them, both V. harveyi and Streptococcus. iniae co-infected one fish. Additionally, three other bacterial strains including Nocardia seriolae, Staphylococcus Saprophyticus, and Photobacterium damselae subsp.damselae were isolated. Microscopic examination mainly observed two parasites, Cryptocaryon irritans and Neobenedenia girellae. In virus detection, the red sea bream iridovirus (RSIV) was mainly detected in L. crocea. Statistical analysis showed that among the fish with detected pathogens, 55.81% (24/43) had bacterial infections, 37.21% (16/43) had parasitic infections, and 37.21% (16/43) had RSIV infections. Among them, five fish had mixed infections of bacteria and parasites, three had mixed infections of bacteria and viruses, three had mixed infections of parasites and viruses, and one L. crocea had mixed infections of viruses, bacteria, and parasites.
UNASSIGNED: These findings indicate that these three major types of diseases are very common in the L. crocea farming area in Ningbo, implying the complexity of mixed infections of multiple diseases.