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, 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.

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.

Osmoregulatory and Hematological Responses of Rainbow Trout (Salmo gairdneri) to Extended Environmental Acidification

1984 ◽  
Vol 41 (11) ◽  
pp. 1686-1694 ◽  
Author(s):  
M. A. Giles ◽  
H. S. Majewski ◽  
B. Hobden
Keyword(s):  
Rainbow Trout ◽  
Osmotic Pressure ◽  
Plasma Concentrations ◽  
Acid Stress ◽  
Plasma Osmolality ◽  
Hemoglobin Concentration ◽  
Ion Concentration ◽  
Salmo Gairdneri ◽  
Plasma Sodium ◽  
Hydrogen Ion Concentration

The dose-dependent relationships of several physiological responses to acid were examined in rainbow trout (Salmo gairdneri) exposed for 22 d to water at pH 4.2–6.0. Significant increases in ventilatory and cardiac rates occurred at pHw < 4.9. Hematocrit and hemoglobin concentration increased progressively with acid stress at pHw < 5.5. Plasma calcium, magnesium, sodium, and chloride concentrations were reduced and plasma phosphate elevated in acid-exposed fish. Seasonal differences were observed in the quantitative responses to acid exposure in the relationship between hematocrit and hemoglobin concentration and in the plasma concentrations of calcium and magnesium. The fractional contribution of sodium and chloride to plasma osmolality decreased linearly with increasing hydrogen ion concentration, and the change in plasma sodium, chloride, and osmolality per unit change in pHw was 35.2 mmol/L, 39.7 mmol/L, and 47.4 mosmol/kg, respectively, in the pH range of 4.5–5.2. We concluded that the discrepancy between the reduction in plasma osmotic pressure and the combined reduction in the major plasma electrolytes is a result of the elevation in concentration of an unidentified plasma solute which offsets 40–45% of the expected reduction in osmotic pressure.

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.

Plasma Cortisol Levels of Fingerling Rainbow Trout (Salmo gairdneri) at Rest, and Subjected to Handling, Confinement, Transport, and Stocking

1980 ◽  
Vol 37 (5) ◽  
pp. 805-811 ◽  
Author(s):  
Bruce A. Barton ◽  
Richard E. Peter ◽  
Christine R. Paulencu
Keyword(s):  
Rainbow Trout ◽  
Plasma Cortisol ◽  
Gradual Increase ◽  
Salmo Gairdneri ◽  
Gradual Decline ◽  
Sharp Rise ◽  
Daily Cycle ◽  
Handling Stress ◽  
Gentle Agitation ◽  
Cortisol Levels

Fingerling rainbow trout, acclimated to hatchery raceways or laboratory aquaria, had low plasma cortisol levels (≤ 2 ng/mL), with no apparent daily cycle in levels. Netting of cohorts out of an aquarium, without agitation, did not cause a rise in plasma cortisol concentrations in remaining fish. However, following 90 s of handling and confinement by netting, fingerlings had a sharp rise in plasma cortisol to a peak at 15 min, and then a gradual decline to the basal level over 2 h. Gentle agitation and intermittent restraint with a dip net in the aquarium caused a gradual increase in plasma cortisol concentrations. Intense handling and severe confinement caused a rapid increase in plasma cortisol to a plateau, two to four times greater than the peak levels found in fingerlings subjected to the less vigorous stressors; high levels of plasma cortisol were maintained to the median tolerance limit. During a stocking operation, there was a rapid rise in plasma cortisol concentrations during the initial capture from the rearing ponds, and high levels were maintained through to stocking into the lake 6 h and 10 min later, although a small decrease occurred during transit while the fish were in the truck tanks. After stocking, plasma cortisol concentrations in caged fingerlings did not decrease to the basal level until 8 d poststocking.Key words: rainbow trout, fingerlings, plasma cortisol, cycles, handling stress, stocking stress

Assessment of the Acute Toxicity, Growth Impairment, and Flesh Tainting Potential of a Bleached Kraft Mill Effluent on Rainbow Trout (Salmo gairdneri)

1977 ◽  
Vol 34 (6) ◽  
pp. 869-878 ◽  
Author(s):  
D. M. Whittle ◽  
K. W. Flood
Keyword(s):  
Rainbow Trout ◽  
Acute Toxicity ◽  
Continuous Flow ◽  
Effluent Treatment ◽  
Salmo Gairdneri ◽  
Freshwater Ecosystem ◽  
Juvenile Rainbow Trout ◽  
Effluent Concentration ◽  
Kraft Mill Effluent ◽  
Kraft Mill

Static and continuous-flow bioassays utilizing juvenile rainbow trout (Salmo gairdneri) were conducted on a northern Ontario bleached kraft mill effluent to assess the range of acute toxicity and related sublethal effects. The acute toxicity of the total mill effluent, as determined by static bioassay procedures, ranged from a 96-h LC50 value of 14–49.0% vol/vol. The results of these bioassays depended on testing methodology and effluent treatment systems employed by the mill when samples were collected. Continuous-flow bioassays conducted on the effluent Produced 96-h LC50 values of 21.8 and 24.8% vol/vol. Growth rate of juvenile rainbow trout (1–2 g) held under continuous-flow conditions for 18 days was significantly reduced at 6% vol/vol effluent concentration (P < 0.05). Flavor of yearling rainbow trout [Formula: see text] exposed to 3% effluent for 48 h was significantly impaired (P < 0.05). This effluent concentration, the lowest level impairing flavor represents approximately 0.12 of the 96-h LC50 derived from continuous-flow bioassays. No significant flavor impairment was detected in fish exposed for 144 h to a 2% effluent concentration Flavor impairment at a 3% vol/vol effluent concentration, the most sensitive sublethal response measured in this study, may also be the most critical response when assessing the economic impact of a kraft mill discharge to a freshwater ecosystem.

Some Toxic Constituents of Chlorination-Stage Effluents from Bleached Kraft Pulp Mills

1981 ◽  
Vol 38 (7) ◽  
pp. 739-743 ◽  
Author(s):  
A. B. McKague
Keyword(s):  
Gas Chromatography ◽  
Rainbow Trout ◽  
Kraft Pulp ◽  
Pulp Mill ◽  
Salmo Gairdneri ◽  
Pulp Mills ◽  
Juvenile Rainbow Trout ◽  
Bleached Kraft Pulp ◽  
Toxic Materials ◽  
Kraft Pulp Mills

Constituents responsible for the toxicity of a sample of bleached kraft chlorination-stage effluent to juvenile rainbow trout (Salmo gairdneri) were investigated. Tetrachlorocatechol, 3,4,5-trichlorocatechol, and 2,6-dichlorohydroquinone were identified and evidence was obtained for the presence of other chlorodihydroxybenzenes in toxic acidic fractions of the sample. Concentrations of 0.46 mg/L 3,4,5-trichloro- and 0.74 mg/L tetrachloro-catechol were estimated in the sample by analytical gas chromatography. Toxic materials in the nonacidic fraction were not identified although the nontoxic dichloromethyl methyl sulfone was isolated.Key words: chlorination-stage effluent, toxicity, pulp mill, chlorocatechols, chlorodihydroxybenzenes

THE EFFECT OF ADRENOCORTICAL STEROIDS ON THE TISSUE ELECTROLYTE COMPOSITION OF THE FRESH-WATER RAINBOW TROUT (SALMO GAIRDNERI)

1963 ◽  
Vol 25 (4) ◽  
pp. 457-464 ◽  
Author(s):  
W. N. HOLMES ◽  
D. G. BUTLER
Keyword(s):  
Rainbow Trout ◽  
Fresh Water ◽  
Experimental Period ◽  
Sodium Concentration ◽  
Significant Rise ◽  
Salmo Gairdneri ◽  
Plasma Sodium ◽  
Adrenocortical Activity ◽  
Transient Rise ◽  
Sodium And Potassium

SUMMARY The effects were studied of cortisol, corticosterone and aldosterone on the concentrations of sodium and potassium in muscle and blood plasma and on water content of muscle in the fresh-water rainbow trout (Salmo gairdneri). These steroids appeared to cause a loss in plasma sodium throughout the 96 hr. experimental period. An initial rise in muscle sodium was observed during the first 24 hr. after commencement of the treatments. The subsequent decline in muscle sodium was interrupted by a transient rise followed by a continuing decline. The effect of these hormones on the potassium concentrations in plasma was variable, although there was a significant rise in the potassium concentration in muscle during the period of decline in sodium concentration. The significance of these results in relation to the possible enhanced adrenocortical activity of the trout during adaptation to a marine environment is discussed.

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