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Effects of fish size and route of infection on virulence of a Danish Yersinia ruckeri O1 biotype 2 strain in rainbow trout (Oncorhynchus mykiss)


Ohtani, M and Villumsen, KR and Strom, HK and Lauritsen, AH and Aalbaek, B and Dalsgaard, I and Nowak, B and Raida, MK and Bojesen, AM, Effects of fish size and route of infection on virulence of a Danish Yersinia ruckeri O1 biotype 2 strain in rainbow trout (Oncorhynchus mykiss), Aquaculture, 503 pp. 519-526. ISSN 0044-8486 (2019) [Refereed Article]

Copyright Statement

2019 Published by Elsevier B.V.

DOI: doi:10.1016/j.aquaculture.2019.01.041


The comparative virulence of Yersinia ruckeri serotype O1 biotype 2 strain 07111224 from a Danish outbreak of enteric redmouth disease in rainbow trout (Oncorhynchus mykiss) was investigated in different sizes of rainbow trout (5, 19, 25 and 52 g) using a panel of challenge methods (bath, intraperitoneal (IP) injection, anal intubation and cohabitation).

The results show that Y. ruckeri 07111224 is virulent enough to successfully cause mortality in 552 g rainbow trout through three different infection routes (bath, IP injection and anal intubation), and strongly suggests that susceptibility to Y. ruckeri infection is dependent on fish size. Bath challenge (108 CFU/ml) caused 79% mortality in 5 g fish, while the mortality in 1952 g fish was approximately 26%. IP injection challenges (105106 CFU/individual) resulted in high mortalites in fish of all sizes. Anal intubation challenges (109 CFU/ individual) induced 82% mortality in 5 g fish and decreased with increasing fish weight. Finally, cohabitation challenges induced 45% mortality in 5 g test fish when test fish were cohabitated 1:1 with shedder fish, while mortalities in test fish of five other challenge groups were lower (525%). Statistical models were fit to the data from each challenge model. The model parameter predictions suggests statistically significant effects of fish weight for bath, IP and anal intubation challenges. Furthermore, they highlight the importance of the ratio of shedders to test fish in cohabitation challenges and of the challenge doses, in particular for the IP challenge model.

Item Details

Item Type:Refereed Article
Keywords:Yersinia ruckeri O1 biotype 2, bath, intraperitoneal injection, anal intubation, cohabitation
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Fisheries sciences
Research Field:Fish pests and diseases
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - aquaculture
Objective Field:Aquaculture fin fish (excl. tuna)
UTAS Author:Nowak, B (Professor Barbara Nowak)
ID Code:130460
Year Published:2019
Web of Science® Times Cited:9
Deposited By:Fisheries and Aquaculture
Deposited On:2019-01-25
Last Modified:2020-01-14

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