Suppression of Saprolegnia infections in rainbow trout (Oncorhynchus mykiss) eggs using protective bacteria and ultraviolet irradiation of the hatchery water |
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Authors: | Jouni Heikkinen Marja Tiirola Satu Maarit Mustonen Päivi Eskelinen Dina Navia‐Paldanius Atte von Wright |
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Institution: | 1. Department of Biosciences, University of Eastern Finland, Kuopio, Finland;2. Department of Biological and Environmental Science, University of Jyv?skyl?, Jyv?skyl?, Finland;3. Department of Environmental Science, University of Eastern Finland, Kuopio, Finland;4. Finnish Game and Fisheries Research Institute, Jyv?skyl? Game and Fisheries Research, Jyv?skyl?, Finland |
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Abstract: | Since formalin is widely used in prevention of Saprolegnia infections in salmonid fish hatcheries, there is a need for more environmentally safe treatment methods. Therefore, we screened 360 bacterial isolates against their ability to antagonize the growth of Saprolegnia parasitica hyphae in vitro, and best strains were selected according to their antagonistic properties and colonization capability on rainbow trout egg surface. Protective bacterial cultures of Pseudomonas sp. M162, Pseudomonas sp. M174 and Janthinobacterium M169 were tested for prevention of Saprolegnia sp. infections during incubation trials of rainbow trout (Oncorhynchus mykiss) eggs with UV irradiated (400 mWs cm?2) and non‐treated inlet water. UV irradiation of inlet water significantly decreased mortality during the incubation. Lowest mortalities were observed in protective culture treated groups incubated with UV‐irradiated inlet water. UV irradiation increased the dominance of the main bacterial colonizers and variation in the bacterial species diversity between the experimental units. |
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Keywords: | Saprolegnia infection eggs rainbow trout UV irradiation protective culture
Pseudomonas
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