Interrenal, Thyroidal, and Carbohydrate Responses of Rainbow Trout (Salmo gairdneri) to Environmental Acidification

1984 ◽  
Vol 41 (1) ◽  
pp. 36-45 ◽  
Author(s):  
S. B. Brown ◽  
J. G. Eales ◽  
R. E. Evans ◽  
Toshiaki J. Hara
Keyword(s):  
Rainbow Trout ◽  
Plasma Glucose ◽  
Plasma Cortisol ◽  
Acid Stress ◽  
Acid Exposure ◽  
Salmo Gairdneri ◽  
Significant Elevation ◽  
Histological Changes ◽  
Treated Fish ◽  
Cortisol Release

Exposure to acid-treated water (H2SO4, pH 6.0–4.2) for 21 d altered interrenal and thyroid function in immature rainbow trout, Salmo gairdneri. At a pH < 5.2 plasma Cortisol increased, implying sustained interrenai Cortisol release. Interrenal histology showed hyperplasia and elevated nuclear diameter at pH 4.7. Eight days of acid exposure (pH 4.7) were required to raise plasma Cortisol significantly. At a pH < 4.7 the ratio of plasma T4 (L-thyroxine) to T3 (3,5,3′-triiodo-L-thyronine) tended to increase in relation to the controls. Depending on the experiment, this was due to either a significant elevation in plasma T4 or a decrease in plasma T3. No histological changes were evident in the thyroid of acid-treated trout. Eight days of acid exposure (pH 4.7) were required to depress plasma T3. Coincidental with higher interrenal activity, plasma glucose was elevated in acid-treated fish (pH < 5.2) after 4 d of exposure. The possible relationships of the endocrinde changes to accompanying acid-induced elevations in plasma glucose and protein and hepatocyte histochemistry are considered, and their possible roles as indices of acid stress are discussed.

Effect of Prior Acid Exposure on Physiological Responses of Juvenile Rainbow Trout (Salmo gairdneri) to Acute Handling Stress

1985 ◽  
Vol 42 (4) ◽  
pp. 710-717 ◽  
Author(s):  
Bruce A. Barton ◽  
Gary S. Weirter ◽  
Cars B. Schreck
Keyword(s):  
Rainbow Trout ◽  
Plasma Glucose ◽  
Plasma Cortisol ◽  
Acid Stress ◽  
Peak Level ◽  
Acid Exposure ◽  
Salmo Gairdneri ◽  
Plasma Sodium ◽  
Handling Stress ◽  
Juvenile Rainbow Trout

Acid-stressed fish appear to be more sensitive to additional stressors than unstressed fish. When juvenile rainbow trout, Salmo gairdneri, were exposed to acid conditions (pH 5.7–4.7) for 5 d, plasma cortisol was affected only slightly during the initial hours of exposure, but plasma glucose and hematocrit increased, and plasma sodium decreased. However, when fish held at pH 4.7 were subsequently subjected to a 30-s handling stress, poststress plasma cortisol rose to a peak level of more than twice that in handled fish held at ambient pH (6.6). Effects of handling on plasma glucose or sodium were not apparent against levels already altered by the chronic acid exposure, judging by the corticosteroid response, we conclude that the acid-stressed fish were more sensitive to additional handling, even though they appeared to be physiologically normal after 5 d. Thus, as a management consideration, when fish are stocked in acidified waters, care should be taken to avoid situations where the fish may encounter additional disturbances in the new environment. Plasma glucose and sodium were better indicators of chronic acid stress alone than plasma cortisol, but the greater cortisol response to handling at low pH may be a useful method of detecting increased interrenal activity during early stages of environmental acidification.

Interrenal, Thyroidal, Carbohydrate, and Electrolyte Responses in Rainbow Trout (Salmo gairdneri) during Recovery from the Effects of Acidification

1986 ◽  
Vol 43 (3) ◽  
pp. 714-718 ◽  
Author(s):  
S. B. Brown ◽  
R. E. Evans ◽  
Toshiaki J. Hara
Keyword(s):  
Rainbow Trout ◽  
Sodium Chloride ◽  
Plasma Glucose ◽  
Plasma Cortisol ◽  
Acid Treatment ◽  
Acid Exposure ◽  
Salmo Gairdneri ◽  
Nuclear Diameter ◽  
Fluid Compartment ◽  
Plasma Electrolytes

Exposure to acid-treated water (H2SO4, pH 4.76) for 21 d increased plasma glucose, protein, and cortisol levels and interrenal nuclear diameter and decreased plasma electrolytes (Na+, Cl−) and osmolality in immature rainbow trout (Salmo gairdneri). Plasma L-thyroxine (T4), 3,5,3′-triiodo-L-thyronine (T3), or their ratio (T4:T3) were not altered by the acid treatment. Following termination of acid exposure, return to control levels was achieved within 1 d by plasma protein, 3 d by plasma cortisol, glucose, sodium, chloride, and osmolality, and 7 d by interrenal nuclear diameter. Thus, within 1 wk the studied aspects of the plasma fluid compartment had recovered from the effects of acid exposure.

Do Rainbow Trout (Salmo gairdneri) Acclimate to Low pH?

1988 ◽  
Vol 45 (8) ◽  
pp. 1399-1405 ◽  
Author(s):  
Céline Audet ◽  
Chris M. Wood
Keyword(s):  
Rainbow Trout ◽  
High Stress ◽  
Acid Stress ◽  
Ammonia Excretion ◽  
Acid Exposure ◽  
Cell Swelling ◽  
Whole Body ◽  
Salmo Gairdneri ◽  
Base Exchange

Adult rainbow trout (Salmo gairdneri) previously exposed to long-term sublethal acid stress (3 mo, pH 4.8) in artificial soft water (Ca2+ = 50, Na+ = 50, Cl− = 100 μeq∙L−1) were challenged with acute severe acid exposure (4.5–5 h, pH 4.0). Their response in terms of whole-body ionic exchanges and blood chemistry was compared with that of trout that had no previous history of acid exposure (naive fish). Acute pH 4.0 exposure caused significant ionoregulatory disturbances in both acid-preexposed and naive fish. Rates of net Na+ and Cl− body losses were twice as large in acid-preexposed fish as in naive fish. The two groups showed similar slight net uptake of acidic equivalents. However, the dynamics of acid–base exchange differed, especially with regard to ammonia excretion which was elevated in acid-preexposed fish and inhibited in naive fish. A larger decrease in plasma Na+, red blood cell swelling, and the maintenance of high-stress indicators (elevated plasma glucose and ammonia excretion, depressed osmolality) confirmed that osmo-ionoregulatory disturbances were more intense in acid-preexposed fish than in naive fish. Thus, long-term sublethal acid exposure did not improve but rather significantly decreased the ability of rainbow trout to respond to more severe acid stress. We conclude that acclimation to acid stress does not occur in rainbow trout.

A Standardized Model of Experimental Furunculosis in Rainbow Trout (Salmo gairdneri)

1980 ◽  
Vol 37 (4) ◽  
pp. 746-750 ◽  
Author(s):  
C. Michel
Keyword(s):  
Rainbow Trout ◽  
Intramuscular Injection ◽  
Infected Fish ◽  
Aeromonas Salmonicida ◽  
Salmo Gairdneri ◽  
Exponential Growth Phase ◽  
Cell Counts ◽  
Viable Cells ◽  
Treated Fish ◽  
Drop Plate

With the aid of published information, we have developed a standardized and reproducible experimental model of furunculosis in rainbow trout (Salmo gairdneri). The infective doses (LD50 = 200 to 2000 germs, i.m.) employed strains of Aeromonas salmonicida, the virulence of which was maintained by passage in 15-g fingerlings. The number of viable cells in the dose was conveniently determined using the drop-plate enumeration technique; however, meaningful cell counts could only be obtained if broth cultures used for infecting the fish were harvested early in the exponential growth phase (OD < 1.000 at 525 nm). Better results were obtained with intramuscular injection than with intraperitoneal injection. The infection procedure involved injecting a dose of 10 LD50, intramuscularly, into each of 30 fish held at 15 °C and recording the mortalities for 10 d. Protection tests in which Tribrissen (28 mg sulfadiazine and 5.6 mg trimethoprim/kg fish for 8 d) was fed or tetracycline (1 mg per fish) i.m. injected into the infected fish served to demonstrate the value of the model. Results were in agreement with field observations with no death for treated fish and a mortality of 96%, for untreated fish. Key wordss rainbow trout, Salmo gairdneri; Aeromonas salmonicida, furunculosis, experimental infection

Liver Damage in Rainbow Trout (Salmo gairdneri) Fed Cyclopropenoid Fatty Acids

1974 ◽  
Vol 31 (8) ◽  
pp. 1397-1400 ◽  
Author(s):  
Y. Malevski ◽  
J. H. Wales ◽  
M. W. Montgomery
Keyword(s):  
Fatty Acids ◽  
Rainbow Trout ◽  
Liver Damage ◽  
Basal Diet ◽  
Experimental Period ◽  
Salmo Gairdneri ◽  
Histological Changes ◽  
Cyclopropenoid Fatty Acids ◽  
Cyclic Changes ◽  
Parenchymal Cells

Histological changes in livers of rainbow trout (Salmo gairdneri) repeatedly fed diets containing cyclopropenoid fatty acids (CPFA) revealed that these fish were unable to develop resistance to liver damage caused by CPFA. One group of trout was fed 150 ppm CPFA in the basal diet for 49 days followed by the basal diet for the remainder of the experimental period. Another group of trout was fed 150 ppm CPFA for 49 days, basal diet for 65 days, and 150 ppm CPFA for 45 days. At this time this group was divided into two subgroups; one received basal diet for 15 days, the other for 30 days, after which both subgroups were placed on a diet containing 360 ppm CPFA for 36 days. Analysis of the livers for histological changes showed that the parenchymal cells underwent cyclic changes of injury and recovery each time the trout were fed CPFA. Complete recovery of parenchymal cells occurred after the fish were removed from the diets containing CPFA for 30 days. Bile duct and blood vessel hyperplasia was observed for as long as 7 mo after CPFA was eliminated from the trout diet.

DIFFERENCES IN CONCENTRATIONS OF PLASMA CORTISOL IN THE TROUT AND THE EEL FOLLOWING ADAPTATION TO BLACK OR WHITE BACKGROUNDS

1981 ◽  
Vol 89 (1) ◽  
pp. 135-140 ◽  
Author(s):  
BRIDGET I. BAKER ◽  
THERESA A. RANCE
Keyword(s):  
Rainbow Trout ◽  
Plasma Cortisol ◽  
Binding Capacity ◽  
Anguilla Anguilla ◽  
Short Photoperiod ◽  
Salmo Gairdneri ◽  
Pars Intermedia ◽  
Total Cortisol ◽  
The Difference ◽  
Long Photoperiod

When rainbow trout (Salmo gairdneri) and eels (Anguilla anguilla) were kept in black tanks for 3—4 weeks, their plasma cortisol titres were about fourfold higher than in fish kept in white tanks. In trout, the difference was apparent only under a long photoperiod of 16 h light: 8 h darkness, but in eels the difference was clear under both a long or short photoperiod (9·5 h light: 14·5 h darkness). It is suggested that the increase in plasma cortisol seen in black-adapted fish is dependent on either ACTH or MSH secreted by the pars intermedia melanotrophs. No difference was seen either in the total cortisol-binding capacity of the plasma nor in interrenal histology in trout from black or white backgrounds.

Long-Term Sublethal Acid Exposure in Rainbow Trout (Salmo gairdneri) in Soft Water: Effects on Ion Exchanges and Blood Chemistry

1988 ◽  
Vol 45 (8) ◽  
pp. 1387-1398 ◽  
Author(s):  
Céline Audet ◽  
R. Stephen Munger ◽  
Chris M. Wood
Keyword(s):  
Rainbow Trout ◽  
Ammonia Excretion ◽  
Blood Chemistry ◽  
Soft Water ◽  
Acid Exposure ◽  
Salmo Gairdneri ◽  
Plasma Parameters ◽  
Water Effects ◽  
Net Flux

Long-term sublethal acid exposure (3 mo, pH 4.8) in adult rainbow trout (Salmo gairdneri) acclimated to artificial soft water (Ca2+ = 50, Na+ = 50, Cl− = 100 μeq∙L−1) caused transient net fosses of Na+ and Cl−. Net flux rates of both ions were returned to control levels after 30–52 d of acid exposure through a new equilibrium between unidirectional influx and efflux, where both were lower than control rates. K+ balance remained negative and Ca2+ balance at zero throughout the exposure. No changes in net acidic equivalent flux occurred, indicating the absence of acid–base disturbance, but ammonia excretion increased over time. Muscle K+, Na+, and Cl− fell and Ca2+ increased. Plasma Na+, Cl−, and osmolality decreased, while plasma protein, glucose, and blood hemoglobin increased during the first few weeks of acid exposure. Plasma K+ and Ca2+ did not change. General stabilization of plasma parameters occurred in concert with the stabilization of Na+ and Cl− flux rates, but no recovery to control levels was observed for any of them. We conclude that despite this stabilization at a new steady state, rainbow trout were physiologically affected in a deleterious manner by chronic sublethal acid exposure in soft water.

Sign in / Sign up

Export Citation Format

Share Document