Effects of graded hypoxia on Atlantic salmon infected with amoebic gill disease

• Published in: Journal of Fish Biology
• Main Authors: Powell, M. D., Fisk, D., Nowak, B. F.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2000
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.2000.tb02210.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.2000.tb02210.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.2000.tb02210.x

Atlantic salmon Salmo salar with amoebic gill disease (AGD) were exposed to a graded hypoxia (135–40 mmHg water P O 2 ) and blood samples analysed for respiratory gases and pH at 119, 79·5 and 40 mmHg water P O 2 . There were no differences in the rate of oxygen uptake between infected and control fish. However, arterial P O 2 , and pH were significantly lower in the infected fish whereas P CO 2 was significantly higher in infected fish compared with controls prior to hypoxia and at 119 mmHg water P O 2 . At 79·5 and 40 mmHg water P O 2 saturation, there were no significant differences in blood P O 2 or pH although blood P CO 2 was elevated in AGD affected fish at 50% hypoxia (79·5 mmHg water P O 2 ). The elevated levels of P CO 2 in fish affected by AGD resulted in a persistent respiratory acidosis even during hypoxic challenge. These data suggest that even though the fish were severely affected by AGD, the presence of AGD while impairing gas transfer under normoxic conditions, did not contribute to respiratory failure during hypoxia.