Van Vliet Danielle, Loch Thomas P, Faisal Mohamed
a Department of Fisheries and Wildlife , College of Agriculture and Natural Resources, Michigan State University , 480 Wilson Road, Room 4, East Lansing , 48824 , Michigan , USA.
b Department of Pathobiology and Diagnostic Investigation , College of Veterinary Medicine, Michigan State University , 1129 Farm Lane, Room 174, East Lansing , 48824 , Michigan , USA.
J Aquat Anim Health. 2015 Dec;27(4):192-202. doi: 10.1080/08997659.2015.1088488.
Bacterial coldwater disease (BCWD), caused by Flavobacterium psychrophilum, threatens wild and propagated salmonids worldwide and leads to substantial economic losses. In addition to being horizontally transmitted, F. psychrophilum can be passed from infected parents to their progeny, furthering the negative impacts of this pathogen. In Michigan, both feral and captive salmonid broodstocks are the gamete sources used in fishery propagation efforts. A 5-year study was initiated to follow the prevalence of systemic F. psychrophilum infections in feral broodstocks of four species (steelhead Oncorhynchus mykiss [potadromous Rainbow Trout]; Coho Salmon O. kisutch; Chinook Salmon O. tshawytscha; and Atlantic Salmon Salmo salar) residing in three Great Lakes watersheds. Additionally, captive broodstocks of four species (Rainbow Trout, Brown Trout Salmo trutta, Lake Trout Salvelinus namaycush, and Brook Trout Salvelinus fontinalis) maintained at two facilities were assessed for the presence of F. psychrophilum. The resultant offspring from each broodstock population were sampled for F. psychrophilum infections multiple times throughout hatchery residency. Using selective flavobacterial culture and PCR confirmation, F. psychrophilum was detected in all broodstocks except the captive Lake Trout and Brook Trout. Logistic regression analysis demonstrated that among the infected feral broodstocks, Chinook Salmon from the Lake Michigan watershed had the highest prevalence of systemic F. psychrophilum infection (mean = 63.2%). Among the captive broodstocks, the Gilchrist Creek strain of Brown Trout had the highest infection prevalence (mean = 5%). Collectively, the captive broodstocks were found to have significantly lower infection prevalence than the feral broodstocks. Despite the high prevalence of systemic F. psychrophilum infections in many broodstock populations, the bacterium was rarely detected in their progeny during hatchery rearing. However, heavy losses associated with clinical BCWD outbreaks did occur. Collectively, our results reinforce that BCWD continues to threaten Great Lakes basin salmonids.
细菌性冷水病(BCWD)由嗜冷黄杆菌引起,对全球野生和养殖的鲑科鱼类构成威胁,并导致重大经济损失。除了水平传播外,嗜冷黄杆菌还可从受感染的亲本传给它们的后代,进一步加剧这种病原体的负面影响。在密歇根州,野生和圈养的鲑科鱼类亲鱼都是渔业繁殖工作中使用的配子来源。一项为期5年的研究开始跟踪四种鱼类(虹鳟Oncorhynchus mykiss[溯河洄游型虹鳟];银大麻哈鱼O. kisutch;大鳞大麻哈鱼O. tshawytscha;以及大西洋鲑Salmo salar)的野生亲鱼中系统性嗜冷黄杆菌感染的流行情况,这些亲鱼生活在三个五大湖流域。此外,对饲养在两个设施中的四种鱼类(虹鳟、褐鳟Salmo trutta、湖鳟Salvelinus namaycush和溪鳟Salvelinus fontinalis)的圈养亲鱼进行了嗜冷黄杆菌检测。在孵化场养殖期间,对每个亲鱼群体产生的后代多次进行采样,检测嗜冷黄杆菌感染情况。通过选择性黄杆菌培养和PCR确认,除了圈养的湖鳟和溪鳟外,在所有亲鱼中都检测到了嗜冷黄杆菌。逻辑回归分析表明,在受感染的野生亲鱼中,密歇根湖流域的大鳞大麻哈鱼系统性嗜冷黄杆菌感染的流行率最高(平均=63.2%)。在圈养亲鱼中,褐鳟的吉尔克里斯特溪菌株感染率最高(平均=5%)。总体而言,发现圈养亲鱼的感染率明显低于野生亲鱼。尽管许多亲鱼群体中系统性嗜冷黄杆菌感染的流行率很高,但在孵化场养殖期间,在它们的后代中很少检测到这种细菌。然而,与临床细菌性冷水病暴发相关的重大损失确实发生了。总体而言,我们的结果强化了细菌性冷水病继续威胁五大湖流域鲑科鱼类的观点。