Cyclic hypoxia exposure accelerates the progression of amoebic gill disease
Amoebic gill disease (AGD), caused by the amoeba Neoparamoeba perurans, has led to considerable economic losses in every major Atlantic salmon producing country, and is increasing in frequency. The most serious infections occur during summer and autumn, when temperatures are high and poor dissolved...
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ftunivtasmania:oai:eprints.utas.edu.au:34524 2023-05-15T15:31:39+02:00 Cyclic hypoxia exposure accelerates the progression of amoebic gill disease Oldham, T Dempster, T Crosbie, P Adams, M Nowak, B 2020 application/pdf https://eprints.utas.edu.au/34524/ https://eprints.utas.edu.au/34524/1/140305%20-%20Cyclic%20hypoxia%20exposure%20accelerates%20the%20progression.pdf en eng MDPIAG https://eprints.utas.edu.au/34524/1/140305%20-%20Cyclic%20hypoxia%20exposure%20accelerates%20the%20progression.pdf Oldham, T, Dempster, T, Crosbie, P orcid:0000-0001-8856-1731 , Adams, M orcid:0000-0002-5737-5474 and Nowak, B orcid:0000-0002-0347-643X 2020 , 'Cyclic hypoxia exposure accelerates the progression of amoebic gill disease' , Pathogens, vol. 9, no. 8 , pp. 1-14 , doi:10.3390/pathogens9080597 <http://dx.doi.org/10.3390/pathogens9080597>. Salmo salar Atlantic salmon aquaculture dissolved oxygen Paramoeba/Neoparamoeba perurans stress Article PeerReviewed 2020 ftunivtasmania https://doi.org/10.3390/pathogens9080597 2021-10-04T22:18:36Z Amoebic gill disease (AGD), caused by the amoeba Neoparamoeba perurans, has led to considerable economic losses in every major Atlantic salmon producing country, and is increasing in frequency. The most serious infections occur during summer and autumn, when temperatures are high and poor dissolved oxygen (DO) conditions are most common. Here, we tested if exposure to cyclic hypoxia at DO saturations of 40–60% altered the course of infection with N. perurans compared to normoxic controls maintained at ≥90% DO saturation. Although hypoxia exposure did not increase initial susceptibility to N. perurans, it accelerated progression of the disease. By 7 days post-inoculation, amoeba counts estimated from qPCR analysis were 1.7 times higher in the hypoxic treatment than in normoxic controls, and cumulative mortalities were twice as high (16 ± 4% and 8 ± 2%), respectively. At 10 days post-inoculation, however, there were no differences between amoeba counts in the hypoxic and normoxic treatments, nor in the percentage of filaments with AGD lesions (control = 74 ± 2.8%, hypoxic = 69 ± 3.3%), or number of lamellae per lesion (control = 30 ± 0.9%, hypoxic = 27.9 ± 0.9%) as determined by histological examination. Cumulative mortalities at the termination of the experiment were similarly high in both treatments (hypoxic = 60 ± 2%, normoxic = 53 ± 11%). These results reveal that exposure to cyclic hypoxia in a diel pattern, equivalent to what salmon are exposed to in marine aquaculture cages, accelerated the progression of AGD in post-smolts. Article in Journal/Newspaper Atlantic salmon Salmo salar University of Tasmania: UTas ePrints Pathogens 9 8 597 |
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Open Polar |
collection |
University of Tasmania: UTas ePrints |
op_collection_id |
ftunivtasmania |
language |
English |
topic |
Salmo salar Atlantic salmon aquaculture dissolved oxygen Paramoeba/Neoparamoeba perurans stress |
spellingShingle |
Salmo salar Atlantic salmon aquaculture dissolved oxygen Paramoeba/Neoparamoeba perurans stress Oldham, T Dempster, T Crosbie, P Adams, M Nowak, B Cyclic hypoxia exposure accelerates the progression of amoebic gill disease |
topic_facet |
Salmo salar Atlantic salmon aquaculture dissolved oxygen Paramoeba/Neoparamoeba perurans stress |
description |
Amoebic gill disease (AGD), caused by the amoeba Neoparamoeba perurans, has led to considerable economic losses in every major Atlantic salmon producing country, and is increasing in frequency. The most serious infections occur during summer and autumn, when temperatures are high and poor dissolved oxygen (DO) conditions are most common. Here, we tested if exposure to cyclic hypoxia at DO saturations of 40–60% altered the course of infection with N. perurans compared to normoxic controls maintained at ≥90% DO saturation. Although hypoxia exposure did not increase initial susceptibility to N. perurans, it accelerated progression of the disease. By 7 days post-inoculation, amoeba counts estimated from qPCR analysis were 1.7 times higher in the hypoxic treatment than in normoxic controls, and cumulative mortalities were twice as high (16 ± 4% and 8 ± 2%), respectively. At 10 days post-inoculation, however, there were no differences between amoeba counts in the hypoxic and normoxic treatments, nor in the percentage of filaments with AGD lesions (control = 74 ± 2.8%, hypoxic = 69 ± 3.3%), or number of lamellae per lesion (control = 30 ± 0.9%, hypoxic = 27.9 ± 0.9%) as determined by histological examination. Cumulative mortalities at the termination of the experiment were similarly high in both treatments (hypoxic = 60 ± 2%, normoxic = 53 ± 11%). These results reveal that exposure to cyclic hypoxia in a diel pattern, equivalent to what salmon are exposed to in marine aquaculture cages, accelerated the progression of AGD in post-smolts. |
format |
Article in Journal/Newspaper |
author |
Oldham, T Dempster, T Crosbie, P Adams, M Nowak, B |
author_facet |
Oldham, T Dempster, T Crosbie, P Adams, M Nowak, B |
author_sort |
Oldham, T |
title |
Cyclic hypoxia exposure accelerates the progression of amoebic gill disease |
title_short |
Cyclic hypoxia exposure accelerates the progression of amoebic gill disease |
title_full |
Cyclic hypoxia exposure accelerates the progression of amoebic gill disease |
title_fullStr |
Cyclic hypoxia exposure accelerates the progression of amoebic gill disease |
title_full_unstemmed |
Cyclic hypoxia exposure accelerates the progression of amoebic gill disease |
title_sort |
cyclic hypoxia exposure accelerates the progression of amoebic gill disease |
publisher |
MDPIAG |
publishDate |
2020 |
url |
https://eprints.utas.edu.au/34524/ https://eprints.utas.edu.au/34524/1/140305%20-%20Cyclic%20hypoxia%20exposure%20accelerates%20the%20progression.pdf |
genre |
Atlantic salmon Salmo salar |
genre_facet |
Atlantic salmon Salmo salar |
op_relation |
https://eprints.utas.edu.au/34524/1/140305%20-%20Cyclic%20hypoxia%20exposure%20accelerates%20the%20progression.pdf Oldham, T, Dempster, T, Crosbie, P orcid:0000-0001-8856-1731 , Adams, M orcid:0000-0002-5737-5474 and Nowak, B orcid:0000-0002-0347-643X 2020 , 'Cyclic hypoxia exposure accelerates the progression of amoebic gill disease' , Pathogens, vol. 9, no. 8 , pp. 1-14 , doi:10.3390/pathogens9080597 <http://dx.doi.org/10.3390/pathogens9080597>. |
op_doi |
https://doi.org/10.3390/pathogens9080597 |
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Pathogens |
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