Appetite of chinook salmon (Oncorhynchus tshawytscha) naturally infected with bacterial kidney disease

Citation
J. Pirhonen et al., Appetite of chinook salmon (Oncorhynchus tshawytscha) naturally infected with bacterial kidney disease, AQUACULTURE, 189(1-2), 2000, pp. 1-10
Citations number
16
Categorie Soggetti
Aquatic Sciences
Journal title
AQUACULTURE
ISSN journal
00448486 → ACNP
Volume
189
Issue
1-2
Year of publication
2000
Pages
1 - 10
Database
ISI
SICI code
0044-8486(20000923)189:1-2<1:AOCS(T>2.0.ZU;2-F
Abstract
We evaluated the use of feed restriction to decrease mortality and infectio n rates in yearling chinook salmon (Oncorhynchus tshawytscha) naturally inf ected with Renibacterium salmoninarum, the causative agent of bacterial kid ney disease (BKD). Fish were purposely stressed and then fed either full ra tion, half ration, or fasted. At the termination of the 6-week experiment, feed intake of the fish was evaluated by X-radiography after feeding all gr oups in excess and the amount of BKD p57 antigen in the kidneys was measure d by enzyme linked immonosorbent assay (ELISA) to assess effects of infecti on on feeding rates. Only a few individuals in, each treatment died during the experiment, but the proportion of fish with detectable antigen concentr ation increased as ration level decreased. Within each treatment, fish with undetectable concentrations of p57 antigen ate significantly more than fis h with elevated antigen levels. Exponential regressions were fitted for eac h ration level describing the decrease of appetite as levels of antigen con centrations increased. The data indicate that even fish that were quite sic k as judged from their relatively high antigen concentrations can still fee d and that previous food shortage can increase the feed intake to some exte nt in the sick fish. (C) 2000 Elsevier Science B.V. All rights reserved.