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Physiological adaptations of rainbow trout to chronically elevated water pH (pH = 9.5)

1996; Wiley; Volume: 274; Issue: 1 Linguagem: Inglês

10.1002/(sici)1097-010x(19960101)274

1097-010X

Michael P. Wilkie, Heather E. Simmons, Chris M. Wood,

Fish Ecology and Management Studies

Journal of Experimental ZoologyVolume 274, Issue 1 p. 1-14 Comparative Physiology and Biochemistry Physiological adaptations of rainbow trout to chronically elevated water pH (pH = 9.5) Michael P. Wilkie, Corresponding Author Michael P. Wilkie Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1===Search for more papers by this authorHeather E. Simmons, Heather E. Simmons Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1Search for more papers by this authorChris M. Wood, Chris M. Wood Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1Search for more papers by this author Michael P. Wilkie, Corresponding Author Michael P. Wilkie Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1===Search for more papers by this authorHeather E. Simmons, Heather E. Simmons Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1Search for more papers by this authorChris M. Wood, Chris M. Wood Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1Search for more papers by this author First published: 1 January 1996 https://doi.org/10.1002/(SICI)1097-010X(19960101)274:1 3.0.CO;2-TCitations: 30AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Recent investigations have demonstrated that rainbow trout cope with acute high pH (pH > 9.0) exposure (lasting 3–8 days) through their ability to counteract high-pH-induced disturbances to ammonia excretion (JAmm), acid-base homeostasis, and electrolyte balance. In the present investigation our goal was to establish how these physiological processes were modulated during chronic (28-day) high pH (pH = 9.5) exposure. Chronic high pH led to minimal mortality, and there were no long-term changes in stress indicators levels, such as cortisol or glucose. JAmm was initially reduced by 40% at high pH but rapidly recovered and fluctuated around control rates, thereafter. Decreased JAmm was associated with an initial 2.5-fold increase in plasma ammonin concentrations (TAmm), followed by a return toward pre-exposure levels after 3 days. Overall, plasma TAmm was slightly higher (40–80%) in the treatment fish, and this likely led to plasma PNH3s that were sufficient to sustain JAmm at high pH. White muscle TAmm stores were also chronically elevated, by 50–100%. There was a transient, twofold elevation of JUrea immediately following high-pH exposure, but by 3 days JUrea had returned to control rates and stabilized thereafter. Plasma ion balance was well maintained at high pH, despite a chronic depression of Na+ influx. Even though there was a persistent respiratory alkalosis at alkaline pH, blood pH was effectively regulated by a simultaneous metabolic acid load, which was not associated with increased lactic acid production. White muscle intracellular pH (pHi) was unaltered during high pH exposure. We conclude that the long-term survival of rainbow trout in alkaline environments is facilitated by higher steady-state internal ammonia concentrations, the development of a sustained, compensatory metabolic acidosis which offsets decreased plasma PCO2, and the effective regulation of plasma electrolyte balance. © 1996 Wiley-Liss, Inc. Citing Literature Volume274, Issue11 January 1996Pages 1-14 RelatedInformation