Compensatory regulation of acid–base balance during salinity transfer in rainbow trout (Oncorhynchus mykiss)

2011 ◽  
Vol 182 (2) ◽  
pp. 259-274 ◽  
Author(s):  
K. M. Gilmour ◽  
S. F. Perry ◽  
A. J. Esbaugh ◽  
J. Genz ◽  
J. R. Taylor ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Acid Base Balance ◽  
Acid Base ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Base Balance ◽  
Compensatory Regulation

Intestinal base excretion in the seawater-adapted rainbow trout: a role in acid-base balance?

1996 ◽  
Vol 199 (10) ◽  
pp. 2331-2343 ◽  
Author(s):  
R Wilson ◽  
K Gilmour ◽  
R Henry ◽  
C Wood
Keyword(s):  
Rainbow Trout ◽  
Potential Role ◽  
Excretion Rate ◽  
Anterior Region ◽  
Acid Base Balance ◽  
Acid Base ◽  
Opsanus Beta ◽  
Base Balance ◽  
High Fluid

A potential role for the intestine of seawater-adapted teleosts in acid­base regulation was investigated following earlier reports of highly alkaline rectal fluids in the gulf toadfish Opsanus beta. Rectal samples taken from starved seawater-adapted rainbow trout had a high fluid pH (8.90±0.03; mean ± s.e.m., N=13) and base (HCO3-+2CO32-) content of 157±26 mequiv kg-1 (N=11). In trout fitted with rectal catheters, rectal fluid was voided at a rate of 0.47±0.11 ml kg-1 h-1 (N=8), giving a net base excretion rate of 114±15 µequiv kg-1 h-1 (N=7). Drinking rates averaged 3.12±0.48 ml kg-1 h-1 (N=8), and accounted for only 6 % of the base excreted via the intestine, indicating substantial net transport of endogenously derived base into the intestine. Rectally excreted base was approximately balanced by an equivalent efflux of net acid from non-rectal sources (possibly as NH4+ excretion via the gills). Samples taken from four sites along the intestine revealed that the most anterior region (the pyloric intestine) was responsible for the majority of HCO3-+2CO32- accumulation. The pyloric intestine was subsequently perfused in situ to investigate possible mechanisms of base secretion. Net base fluxes were found to be dependent on luminal Cl-, 76 % stimulated by amiloride, 20 % inhibited by 10(-4) mol l-1 acetazolamide, but unaffected by either 10(-4) mol l-1 SITS or 2x10(-5) mol l-1 DIDS. This suggests that the mechanism of base secretion within the pyloric intestine may involve a Cl-/HCO3--ATPase. It is speculated that intestinal base secretion may play a role in facilitating osmoregulation of seawater-adapted teleosts.

The effects of five fish anaesthetics on acid–base balance, hematocrit, blood gases, cortisol, and adrenaline in rainbow trout

1989 ◽  
Vol 67 (8) ◽  
pp. 2065-2073 ◽  
Author(s):  
George K. Iwama ◽  
James C. McGeer ◽  
Mark P. Pawluk
Keyword(s):  
Carbon Dioxide ◽  
Rainbow Trout ◽  
Blood Gases ◽  
Dorsal Aorta ◽  
Acid Base Balance ◽  
Acid Base ◽  
Carbon Dioxide Gas ◽  
Blood Ph ◽  
Base Balance ◽  
Deep Anaesthesia

Some physiological aspects of five fish anaesthetics in rainbow trout were investigated. The effects of benzocaine, 2-phenoxyethanol, MS-222 (Sandoz), metomidate, and carbon dioxide gas (CO2) on acid–base regulation, hematocrit, blood gases, and cortisol and adrenaline concentrations were determined in resting rainbow trout fitted with chronic catheters in the dorsal aorta. A severe hypoxia developed with the cessation of breathing in deep anaesthesia. This was accompanied by a rise in blood [Formula: see text] and adrenaline concentration, and a fall in blood pH. Blood bicarbonate concentrations remained unchanged and cortisol concentrations declined with time. There was a transient increase in hematocrit coinciding with the increase in adrenaline concentrations.

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