Mechanisms of aluminium extraction and accumulation at the gills of rainbow trout, Oncorhynchus mykiss (Walbaum), in acidic soft water

Juvenile rainbow trout (Oncorhynchus mykiss, 5–13 g) became acclimated (i.e., increased their resistance to lethal Al levels, 162 μg∙L−1, pH 5.2) after only 5 d when exposed to sublethal AS (38 μg∙L−1) in acidified soft water (Na+ = 85, Ca2+ = 28 μEq∙L−1, pH 5.2). Acclimation was associated with reduced ionoregulatory and respiratory disturbances during lethal Al challenge and was maintained for at least 34 d. Acclimation was relatively specific to Al because no consistently improved resistance to lethal Cu (32 μg∙L−1, pH 5.2) was observed. Exposure to sublethal acid alone (pH 5.2) did not result in acclimation to lethal [H+] (pH 4.0) and caused a pronounced reduction in whole-body Na+ and Cl−. Sublethal acid + Al resulted in a more rapid loss of ions than sublethal acid alone over the first 10 d, but both groups subsequently recovered ionoregulatory status after 34 d. Exposure to sublethal acid alone had a negligible effect on feeding or growth. However, growth was impaired by 29% in Al-exposed trout, primarily the result of reduced appetite during the first 10 d. Decreased growth must be considered one of the costs of acclimation during chronic sublethal exposure to Al.

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Protective effects of calcium against the physiological effects of exposure to a combination of cadmium and copper in rainbow trout (Oncorhynchus mykiss)

Canadian Journal of Zoology ◽

10.1139/z99-070 ◽

1999 ◽

Vol 77 (7) ◽

pp. 1035-1047 ◽

Cited By ~ 7

Author(s):

Jeff G Richards ◽

Richard C Playle

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Plasma Concentrations ◽

Lactate Concentration ◽

Haemoglobin Concentration ◽

Arterial Oxygen Tension ◽

Soft Water ◽

Arterial Oxygen ◽

Cd Accumulation ◽

Rainbow Trout Oncorhynchus Mykiss

We report that an elevated aqueous calcium (Ca) concentration protects against acute respiratory and osmoregulatory action due to exposure to a combination of cadmium (Cd) and copper (Cu) in rainbow trout (Oncorhynchus mykiss), but does not protect against longer term ionoregulatory disruption. Trout exposed to 0.18 µM Cd and 0.80 µM Cu in soft water (40 µM Ca, 440 µM Na, pH 6.6) experienced a 60-torr decrease in arterial oxygen tension, a 5.5 mM increase in blood lactate concentration, and severe haemoconcentration as indicated by a 1.4-fold decrease in mean cell haemoglobin concentration, all of which occurred within 24 h. The addition of Ca to soft water (to reach 910 µM Ca, added as CaCl2; 430 µM Na, pH 6.8) eliminated these severe effects and slowed Cd uptake by the gills, plasma, and liver of trout, probably through competition for binding at gill Ca channels, but Ca did not affect Cu uptake by the gills or its entry into the plasma. Associated with slower Cd accumulation and unchanged Cu accumulation in the plasma were slow decreases in plasma concentrations of Na, Cl, and Ca, which were prevented initially by adding Ca to the water. Modelling using a modified aqueous chemistry computer program, MINEQL+, and previously published gill binding constants accurately simulated the initial (18 h) accumulation of Cd and Cu by trout gills and thus predicted acute toxicity, but our model did not adequately simulate the physiological mechanisms of Cd accumulation by trout gills over longer exposures up to 130 h.

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PHYSIOLOGICAL EFFECTS OF CHRONIC COPPER EXPOSURE TO RAINBOW TROUT (ONCORHYNCHUS MYKISS) IN HARD AND SOFT WATER: EVALUATION OF CHRONIC INDICATORS

Environmental Toxicology and Chemistry ◽

10.1897/1551-5028(2000)019<2298:peocce>2.3.co;2 ◽

2000 ◽

Vol 19 (9) ◽

pp. 2298 ◽

Cited By ~ 13

Author(s):

Lisa N. Taylor ◽

James C. McGeer ◽

Chris M. Wood ◽

D. Gordon McDonald

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Soft Water ◽

Physiological Effects ◽

Copper Exposure ◽

Rainbow Trout Oncorhynchus Mykiss

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Perivitelline Fluid pH of Rainbow Trout (Oncorhynchus mykiss) Eggs in Relation to Ambient pH

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f89-256 ◽

1989 ◽

Vol 46 (12) ◽

pp. 2070-2073 ◽

Cited By ~ 11

Author(s):

B. Kügel ◽

R. H. Peterson

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Weak Acid ◽

Soft Water ◽

Buffer Solution ◽

Ph Change ◽

Ph Buffering ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Significant Difference ◽

Perivitelline Fluid

In soft water of various pH levels, the perivitelline fluid of late eyed rainbow trout (Oncorhynchus mykiss) eggs showed significant pH buffering: final perivitelline pH was higher than ambient by 0.7–0.85 pH unit in acidified water but was lower by 0.3–1.0 pH unit in weak acidified or basic water. No significant difference between the pH of an external buffer solution and that of the perivitelline fluid could be observed after 24 h. Most rapid perivitelline pH change occurred in the first 2 h and in the first 10–20 min, when eggs were transferred from acidified to weak acid or basic water and buffer, respectively. Final pH of the perivitelline fluid was reached after 48 h in unbuffered water and 24 h or less in buffer.

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