Suppression ofSaprolegniainfections in rainbow trout (Oncorhynchus mykiss) eggs using protective bacteria and ultraviolet irradiation of the hatchery water

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.

Saprolegnia parasitica Isolated from Rainbow Trout in Korea: Characterization, Anti-Saprolegnia Activity and Host Pathogen Interaction in Zebrafish Disease Model

“…At present, effective control of S. parasitica is one of the main challenges in salmonid aquaculture. Wide array of chemicals [ 8 ], natural products [ 9 ], bacterial isolates, and UV irradiation [ 10 ] have been researched on to find the replacement or alternative strategies for banned malachite green and to develop environmentally safe treatment methods. Anti- Saprolegnia agents such as formalin [ 11 ], boric acid [ 1 ], clotrimazole [ 12 ], potassium permanganate [ 5 ], copper nitrate [ 13 ], and copper sulfate [ 14 ] have been tested, however, none of them have matched with the efficacy level for killing the pathogen.…”

Possible Mechanisms of Action of Two Pseudomonas fluorescens Isolates as Probiotics on Saprolegniosis Control in Rainbow Trout (Oncorhynchus mykiss Walbaum)

“…Probiotics have been proposed as one of the alternatives to the chemical treatments currently used in aquaculture [3,4]. Recently, the possible usefulness of certain microorganisms, mainly bacteria, has been highlighted as a potential biocontrol for saprolegniosis [5][6][7][8][9][10][11].…”

Biocontrol of saprolegniosis in rainbow trout (Oncorhynchus mykiss Walbaum) using two bacterial isolates (LE89 and LE141) of Pseudomonas fluorescens

“…, Pseudomonas alcaligenes, Pseudomonas saccharophila, Aeromonas caviae and Aeromonas eucrenophila (Hussein & Hatai, ), Serratia marcescens (Zhang, Yang, Li, & Gao, ), Bacillus subtilis (Liu, Lu, Liu, & Zhou, ), Aeromonas media (Lategan & Gibson, ), Aeromonas sobria, Pantoea agglomerans, Serratia fonticola, Xhantomonas reflexus and Yersinia kristensenii (Carbajal‐González et al, ), Lactobacillus plantarum (Nurhajati, Atira, & Kadek Indah, ) and Pseudomonas aeruginosa (Moghaddam, Hajimoradloo, Ghiasi, & Ghorbani, ). However, their action in vivo has only been studied in eel Anguilla australis (Lategan et al ), silver perch Bidyanus bidyanus (Lategan et al ) and eggs of rainbow trout Oncorhynchus mykiss during incubation (Heikkinen et al, ).…”

“…Hajimoradloo, Ghiasi, & Ghorbani, 2012). However, their action in vivo has only been studied in eel Anguilla australis (Lategan et al 2004a), silver perch Bidyanus bidyanus (Lategan et al 2004b) and eggs of rainbow trout Oncorhynchus mykiss during incubation (Heikkinen et al, 2016).…”