Branchial mechanisms of ion and acid–base regulation in the freshwater rainbow trout, Salmo gairdneri

1988 ◽  
Vol 66 (12) ◽  
pp. 2699-2708 ◽  
Author(s):  
D. G. McDonald ◽  
E. T. Prior
Keyword(s):  
Lactic Acid ◽  
Rainbow Trout ◽  
Sodium Bicarbonate ◽  
Ammonium Sulphate ◽  
Ammonia Excretion ◽  
Salmo Gairdneri ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance

Blood acid–base balance and branchial fluxes of Na+, Cl−, and acidic equivalents were examined in rainbow trout (Salmo gairdneri) in response to variations in external [NaCl] and following experimental acid or base loads (intravascular infusion of ammonium sulphate, lactic acid, or sodium bicarbonate). NaCl influx, NaCl efflux, and ammonia excretion covaried with external [NaCl]. Large fluxes of acidic equivalents across the gills were produced by infusion of both ammonium sulphate and sodium bicarbonate, but both treatments had little effect upon Na+ and Cl− uptake. We interpret this result as indicating that apical [Formula: see text] and [Formula: see text] exchange played little role in the branchial clearance of acidic equivalents. Instead, the results are consistent with the notion that acidic equivalents were excreted via diffusion through paracellular channels. A model is presented which suggests that the paracellular channels are the normal route for ionic efflux across the gills and that excretion of acidic equivalents results from modulation of the permselectivity of this pathway.

Blood respiratory properties of rainbow trout (Salmo gairdneri) kept in water of high CO2 tension

1977 ◽  
Vol 67 (1) ◽  
pp. 37-47 ◽  
Author(s):  
F. B. Eddy ◽  
J. P. Lomholt ◽  
R. E. Weber ◽  
K. Johansen
Keyword(s):  
Rainbow Trout ◽  
Control Fish ◽  
Salmo Gairdneri ◽  
Acid Base Balance ◽  
Acid Base ◽  
High Co2 ◽  
Plasma Bicarbonate ◽  
O2 Transport ◽  
Blood Ph ◽  
Base Balance

1. Blood O2 transport and acid-base balance were studied at 20 degrees C in rainbow trout (Salmo gairdneri) which had been kept in water of high CO2 content (15 mmHg) for at least a week. Also the blood gas chemistry of fish rapidly entering or leaving the hypercapnic environment was studied. 2. Fish entering high CO2 water suffered a sharp decrease in blood pH which significantly reduced O2 transport by the blood, but after a few hours considerable compensation was achieved. 3. After at least a week in high CO2 water, trout showed elevated plasma bicarbonate and PCO2 levels, and a decrease in plasma chloride, while pH was about 0 - 1 pH unit below the level for control fish. Oxygen transport by the blood was marginally reduced. 4. Hypercapnic fish rapidly entering fresh water showed a sharp increase in blood pH and a decrease in blood PO2. These parameters regained normal values after a few hours but plasma bicarbonate and chloride levels took much longer to regain control concentrations. 5. Acid-base balance in hypercapnic fish is discussed with particular reference to the role of the branchial ion exchanges.

The Stress of Formalin Treatments in Rainbow Trout (Salmo gairdneri) and Coho Salmon (Oncorhynchus kisutch)

1971 ◽  
Vol 28 (12) ◽  
pp. 1899-1904 ◽  
Author(s):  
Gary Wedemeyer
Keyword(s):  
Rainbow Trout ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Acid Base Balance ◽  
Acid Base ◽  
Blood Ph ◽  
Base Balance ◽  
Ventilation Rates ◽  
Gill Function

Changes in gill function, acid–base balance and pituitary activation occurring during standard 200 ppm formalin treatments of juvenile rainbow trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch) were compared. Plasma Cl−, Ca++, total CO2, and interrenal vitamin C in the trout declined continuously and in proportion to the exposure time, but the salmon were able to maintain these metabolic parameters at approximately initial levels. Blood pH and alkaline reserve regulation of the salmon was also less affected by formalin treatments, especially during prolonged exposures. The oxygen consumption of both species was depressed, but substantially more so in the trout than could be accounted for by decreased ventilation rates. Little frank hemolysis occurred in either species, but there was a significant bilirubinemia in the trout.

Acid-base balance in rainbow trout (Salmo gairdneri) subjected to acid stresses

1976 ◽  
Vol 64 (1) ◽  
pp. 159-171
Author(s):  
F. B. Eddy
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Ambient Water ◽  
Carbon Dioxide Content ◽  
Acid Base Balance ◽  
Acid Base ◽  
Control Value ◽  
Blood Ph ◽  
Base Balance ◽  
Ambient Co2

1. The respiratory properties of rainbow-trout blood were investigated in acid-stressed fish. In the first group acid was introduced into the bloodstream and in the second the carbon dioxide content of the ambient water was increased. 2. Initially the introduction of acid to the blood caused a decrease in blood pH and bicarbonate, and increases in oxygen uptake and ventilation volume. After 2–3 h these values had returned to the control levels. 3. Trout subjected to high ambient CO2 (about 10 mmHg) showed a decrease in blood pH while PCO2 and bicarbonate increased. After 8 h the trout began to show signs of compensation to the acidosis. 4. In each experiment the blood PO2 was little changed but blood O2 content was decreased and tended not to resume the control value even after several hours. 5. The results are discussed in terms of the various acid-base mechanisms thought to be available to the fish. These include branchial ion exchanges and the possible buffering roles of the extracellular and intracellular fluids.

Blood ionic and acid–base status in rainbow trout (Salmo gairdneri) following rapid transfer from freshwater to seawater: effect of pseudobranch denervation

1981 ◽  
Vol 59 (6) ◽  
pp. 1126-1132 ◽  
Author(s):  
S. F. Perry ◽  
T. A. Heming
Keyword(s):  
Rainbow Trout ◽  
Partial Pressure ◽  
Salmo Gairdneri ◽  
Osmotic Regulation ◽  
Acid Base Balance ◽  
Acid Base ◽  
Acid Base Equilibrium ◽  
Base Balance ◽  
Acid Base Status ◽  
Rapid Transfer

Effect of pseudobranch denervation on the ability of Salmo gairdneri to regulate blood ionic and acid–base balance was investigated in freshwater and following transfer to seawater. Denervation of the pseudobranch did not affect internal ionic or acid–base equilibrium in freshwater. Plasma [Cl−], [Na+], pH, total [Formula: see text], and partial pressure of [Formula: see text] of trout were affected by transfer from freshwater to seawater, and by transfer back to freshwater. These ionic and acid–base responses were not affected by denervation of the pseudobranch. It is concluded that alone, the pseudobranch plays little or no role in ionic and osmotic regulation during transfer between freshwater and seawater.

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.

Nitrogen excretion in germ-free and conventional chickens: effects of an alkali load

1978 ◽  
Vol 39 (1) ◽  
pp. 99-104 ◽  
Author(s):  
J. Okumura ◽  
D. Hewitt ◽  
Marie E. Coates
Keyword(s):  
Amino Acids ◽  
Uric Acid ◽  
Ammonia Excretion ◽  
Nitrogen Excretion ◽  
Acid Base Balance ◽  
Acid Base ◽  
Total N ◽  
Germ Free ◽  
Base Balance ◽  
Micro Organisms

1. Groups of three colostomized germ-free (GF) and conventional (CV) chickens aged 4 months were maintained for successive periods of 8 d on a diet containing 200 g casein/kg without and with sodium bicarbonate at the rate of 20 mmol/d and a nitrogen-free diet without and with NaHCO3at 9 mmol/d. Urine and faeces were collected during the last 3 d of each period.2. Total N, uric acid- and ammonia-N were determined in urine and total N in faeces. Amino acids were measured in hydrolysates of faeces collected during the periods when no NaHCO3was included in the diets.3. The CV birds excreted more N on the casein diets but less on the N-free diets than did their GF counterparts, the differences being mainly shown in the urine.4. On both diets hydrolysates of the faeces of CV birds contained smaller amounts of amino acids. On the N-free diet the proportions (g/160 g N) of serine, proline and threonine were reduced, suggesting some conservation of endogenous N by micro-organisms, and the proportions of histidine, alanine, lysine and methionine increased, possibly through microbial synthesis; on the casein diet, proportions of most amino acids were less, probably because bacterial deamination had occurred.5. Urinary excretion of total N, uric acid and ammonia was much greater on the casein than on the N-free diets. Inclusion of NaHCO3caused a sharp fall in urinary ammonia on both diets and in both environments.6. It was concluded that the level of dietary protein and the regulation of acid-base balance have more effect than microbial activity on the urinary ammonia excretion.

Decrease in ureagenesis by partial hepatectomy does not influence acid-base balance

1989 ◽  
Vol 257 (4) ◽  
pp. F696-F699
Author(s):  
T. Almdal ◽  
H. Vilstrup ◽  
K. Bjerrum ◽  
L. O. Kristensen
Keyword(s):  
Sodium Chloride ◽  
Sodium Bicarbonate ◽  
Synthesis Rate ◽  
Urea Synthesis ◽  
Ph Homeostasis ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
Bicarbonate Infusion

It has been suggested that urea synthesis participates directly in body pH homeostasis by removal of bicarbonate. To elucidate this hypothesis sodium bicarbonate or sodium chloride was infused (11.5 mumol/min) for 90 min into control rats and into rats that had undergone an 85% hepatectomy immediately before starting the infusion. Urea synthesis rate was 2.6 +/- 0.3 mumol/min (mean +/- SE) in controls, and was significantly (P less than 0.01) reduced to 1.0 +/- 0.2 mumol/min in partially hepatectomized rats. At the start of bicarbonate infusion, pH was 7.38 and 7.34 in control and partially hepatectomized rats, respectively, and at the end of infusion, pH was 7.56 and 7.51. Standard bicarbonate at start of bicarbonate infusion was 21.9 and 21.3 mM in controls and partially hepatectomized, respectively, and it increased to 32.7 and 29.9 mM at end of infusion. In saline-infused rats a slight decrease of approximately 0.05 pH units was observed during the experiment, but again no difference emerged between control and partially hepatectomized rats. It is concluded that a major role of the liver in the regulation of acid-base balance is unlikely.

Sign in / Sign up

Export Citation Format

Share Document