Abstract：
The present work is the first comprehensive study of fungus-like stramenopilous organisms (Oomycota) diversity in Lithuanian fish farms aimed at proper identification of saprolegniasis pathogens, which is important for water quality control, monitoring infection levels and choosing more effective treatments for this disease in aquaculture. Pathogenic to fish, Saprolegnia and other potentially pathogenic water moulds were isolated from adult fish, their eggs, fry and from water samples. All detected isolates were examined morphologically and confirmed by sequence-based molecular methods. A total of eight species belonging to the genera Saprolegnia, Achlya, Newbya and Pythium were identified. Four species (S. parasitica, S. ferax, S. australis and S. diclina) were found to be the main causative agents of saprolegniasis in Lithuania. S. parasitica and S. ferax dominated both in hatcheries and open fishponds, accounting for 66.2% of all isolates. S. parasitica was isolated from all farmed salmonid fish species as well as from the skin of Cyprinus carpio, Carassius carassius and Perca fluviatilis. S. australis was isolated from water and once from the skin of Oncorhynchus mykiss, and S. diclina was detected only once on the skin of Salmo salar fish. In addition, Achlya ambisexualis, Saprolegnia anisospora and Newbia oligocantha isolated during this study are noted as a possible source of saprolegniasis. The results of this study are relevant for assessing the risk of potential outbreaks of saprolegniasis or other saprolegnia-like infection in Lithuanian freshwater aquaculture.
摘要：
目前的工作是对立陶宛养鱼场中的类真菌类杂种生物（Oomycota）多样性的首次全面研究，旨在正确鉴定腐殖质病原体，这对水质控制很重要，在水产养殖中监测感染水平并选择更有效的治疗方法。对鱼类有致病性，从成年鱼中分离出了腐殖质和其他潜在的致病性水霉，他们的鸡蛋,油炸和水样。所有检测到的分离株都进行了形态学检查，并通过基于序列的分子方法进行了确认。总共有8种属于腐竹属，Achlya,鉴定了Newbya和Pythium。四个物种（S。寄生,S.Ferax,在立陶宛，发现S.australis和S.diclina）是腐殖质病的主要病原体。S.parasitica和S.Ferax在孵化场和开放鱼塘中都占主导地位，占所有分离株的66.2%。从所有养殖的鲑鱼种类以及鲤鱼的皮肤中分离出寄生虫，carassiuscarassius和Percafluviatilis。南氏从水中分离出来，一次从Oncorhynchusmykiss的皮肤中分离出来，在Salmosalar鱼的皮肤上只检测到一次。此外,Achlya双性恋者,在这项研究中分离出的腐殖质孢子和Newbiaoligocanitha被认为是腐殖质病的可能来源。这项研究的结果与评估立陶宛淡水水产养殖中腐殖质病或其他腐殖质样感染的潜在爆发风险有关。
