Effect of ambient salinity on ionic and osmotic regulation of eggs, larvae, and alevins of rainbow trout (Salmo gairdneri)

1978 ◽  
Vol 56 (4) ◽  
pp. 571-577 ◽  
Author(s):  
A. C. Y. Shen ◽  
J. F. Leatherland
Keyword(s):  
Rainbow Trout ◽  
Water Content ◽  
Developmental Stages ◽  
Sea Water ◽  
Salmo Gairdneri ◽  
Distilled Water ◽  
Tissue Water ◽  
Osmotic Concentration ◽  
Perivitelline Fluid ◽  
Early Developmental

The osmotic concentration of the perivitelline fluid in eggs of rainbow trout (Salmo gairdneri) was lower in eggs maintained in distilled water than in eggs maintained in dilute artificial sea water (11‰ and 13‰). The water content of eggs, larvae, and alevins in distilled water was significantly higher than in comparable developmental stages in dilute sea water. Similarly, differences were found in the tissue Na+, K+, and Na+:K+ ratios of eggs, larvae, and alevins reared in the different ambient salinities. These data suggest that the early developmental stages of rainbow trout possess a limited capacity for osmotic or ionic regulation. Larvae appear to regulate tissue Na+ content by increasing the Na+ concentration of the perivitelline space and alevins tolerate an increase in tissue K+ content and a small decrease in tissue water content.

Acid-Base Regulation Following Exhaustive Exercise: A Comparison Between Freshwaterand Sea Water-Adapted Rainbow Trout (Salmo Gairdneri)

1989 ◽  
Vol 141 (1) ◽  
pp. 407-418 ◽  
Author(s):  
Y. TANG ◽  
D. G. McDONALD ◽  
R. G. BOUTILIER
Keyword(s):  
Rainbow Trout ◽  
Sea Water ◽  
Environmental Water ◽  
Exhaustive Exercise ◽  
Salmo Gairdneri ◽  
Acid Base ◽  
Genetic Stock ◽  
Arterial Blood ◽  
Blood Ph ◽  
Counter Ions

Blood acid-base regulation following exhaustive exercise was investigated in freshwater- (FW) and seawater- (SW) adapted rainbow trout (Salmo gairdneri) of the same genetic stock. Following exhaustive exercise at 10°C, both FW and SW trout displayed a mixed respiratory and metabolic blood acidosis. However, in FW trout the acidosis was about double that of SW trout and arterial blood pH took twice as long to correct. These SW/FW differences were related to the relative amounts of net H+ equivalent excretion to the environmental water, SW trout excreting five times as much as FW trout. The greater H+ equivalent excretion in SW trout may be secondary to changes in the gills that accompany the adaptation from FW to SW. It may also be related to the higher concentrations of HCO3− as well as other exchangeable counter-ions (Na+ and Cl−) in the external medium in SW compared to FW.

Onset and rate of drinking in rainbow trout (Salmo gairdneri) following transfer to dilute seawater

1979 ◽  
Vol 57 (10) ◽  
pp. 1863-1865 ◽  
Author(s):  
Roger M. Evans
Keyword(s):  
Rainbow Trout ◽  
Water Balance ◽  
Water Loss ◽  
Sea Water ◽  
Direct Method ◽  
Anguilla Japonica ◽  
Japanese Eel ◽  
Salmo Gairdneri ◽  
Normal Water ◽  
A Direct Method

Seawater-adapted teleosts drink to offset water loss by osmosis. A direct method of monitoring drinking by implanting a fistula to drain the stomach indicated that rainbow trout began drinking from about 9 to 12 (range 1 to 22) h after being placed in 15‰ sea water. Unlike the Japanese eel (Anguilla japonica). in which the onset of drinking has been shown to be immediate and reflex-like, the onset of drinking in trout appears to occur only after appreciable water has been lost to the medium. The trout resembles the eel in that the capacity to shallow water in the absence of postingestional negative feedback exceeds the rate of drinking required to maintain normal water balance.

scholarly journals On the Mechanism of Sodium Extrusion across the Irrigated Gill of Sea Water-Adapted Rainbow Trout (Salmo gairdneri)

1974 ◽  
Vol 64 (2) ◽  
pp. 148-165 ◽  
Author(s):  
Leonard B. Kirschner ◽  
Lewis Greenwald ◽  
Martin Sanders
Keyword(s):  
Rainbow Trout ◽  
Active Component ◽  
Sea Water ◽  
Salmo Gairdneri ◽  
Sodium Efflux ◽  
Exchange Diffusion ◽  
The Difference ◽  
Sodium Extrusion ◽  
Trout Gill ◽  
Electrical Data

Sodium efflux (JoutNa) across the irrigated trout gill was rapid in sea water (SW), but only about 25 % as large in fresh water (FW). The difference correlated with a change in the potential difference across the gill (TEP). The latter was about +10 mV (blood positive) in SW, but –40 mV in FW. Both flux and electrical data indicated that gills in this fish are permeable to a variety of cations including Na+, K+, Mg2+, choline, and Tris. They are less permeable to anions; PNa:PK:PCl was estimated to be 1:10:0.3, and PCl > Pgluconate. The TEP was shown to be a diffusion potential determined by these permeabilities and the extant ionic gradients in SW, FW as well as in other media. JoutNa appeared to be diffusive in all of the experiments undertaken. Exchange diffusion need not be posited, and the question of whether there is an active component remains open.

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