Effects of Available Dietary Carbohydrate and Water Temperature on the Chronic Toxicity of Waterborne Copper to Rainbow Trout (Salmo gairdneri)

1985 ◽  
Vol 42 (5) ◽  
pp. 1007-1013 ◽  
Author(s):  
D. G. Dixon ◽  
J. W. Hilton
Keyword(s):  
Rainbow Trout ◽  
Water Temperature ◽  
Chronic Toxicity ◽  
Elevated Serum ◽  
Free Water ◽  
Growth Period ◽  
Salmo Gairdneri ◽  
Dietary Carbohydrate ◽  
Mortality Trends ◽  
The Impact

We used a factorial design to determine the effects of dietary carbohydrate content (0.1 or 25.6%) and temperature (10 or 15 °C) on the chronic toxicity of waterborne copper (0 or 144 μg Cu∙L−1) to rainbow trout (Salmo gairdneri) over a 12-wk period. Relative to those on the low-carbohydrate (LC) diet, trout reared on the high-carbohydrate (HC) diet developed enlarged, glycogen-filled livers and attained reduced final mean wet body weights. This response was more pronounced at 10 than at 15 °C. Whereas Cu exposure had no significant effect on the growth or mortality of either LC or HC fish at 15 °C, or LC fish at 10 °C, HC fish at 10 °C showed significantly reduced final weight and increased mortality. Trends toward reduced liver glycogen and increased serum glucose, characteristic of chronic stress, were apparent in all Cu-exposed fish. In Cu-free water, mean Cu concentrations in liver tissue of HC fish were significantly lower than those in LC fish at both temperatures. Copper exposure resulted in significant increases in liver Cu concentration for all diet treatments except HC at 10 °C. Elevated serum sorbitol dehydrogenase levels, indicative of hepatic damage, were apparent in Cu-HC fish at 15 °C and in HC, Cu-HC, and Cu-LC fish at 10 °C. No treatment effects on either serum protein or hematocrit were evident. The treatments during the growth period affected subsequent lethal tolerance of Cu. While the 96-h Cu LC50 was not significantly altered by diet alone at 15 °C, it was elevated in HC fish, relative to LC fish at 10 °C. The Cu LC50 of Cu preexposed fish was significantly elevated, relative to parallel groups held in Cu-free water, for LC fish at both 10 and 15 °C. This acclimation to Cu was not apparent in HC fish at either temperature: no significant elevation in LC50 occurred as a result of preexposure. We conclude that increased dietary carbohydrate can significantly increase the chronic toxicity of Cu to trout, and that the impact is enhanced by reduced water temperature.

Acute and Chronic Toxicity of Waterborne Arsenite to Rainbow Trout (Oncorhynchus mykiss)

1994 ◽  
Vol 51 (2) ◽  
pp. 372-380 ◽  
Author(s):  
M. G. Rankin ◽  
D. G. Dixon
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Chronic Toxicity ◽  
Plasma Lipid ◽  
Free Water ◽  
Gallbladder Wall ◽  
Whole Body ◽  
Growth Study ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Wet Weight

The 144-h LC50 (95% fiducial limits) of arsenite for 4.5-g rainbow trout (Oncorhynchus mykiss) was 18.5 (17.9–19.1) mg∙L−1. In a pair-fed growth study which exposed trout to 0.0, 0.76, 2.48, or 9.64 mg arsenite∙L−1 over 17 wk, growth was significantly reduced (by 55%) only at 9.64 mg∙L−1. The reduction was attributable to both reduced appetite (primarily) and direct metabolic impact (marginally). Fish at 9.64 mg∙L−1 suffered 10% mortality, usually associated with necrotic erosion of the mandibular and olfactory regions of the head. All fish exposed to 9.64 mg∙L−1 showed inflammation of the gallbladder wall, a lesion absent at lower exposure concentrations. There were no arsenite impacts on hepato- and splenosomatic index, hematocrit, hemoglobin, total plasma lipid, cholesterol, and protein or brain concentrations of norepinephrine, dopamine, and serotonin. Exposure to 0.0, 0.76, 2.48, and 9.64 mg arsenite∙L−1 for 26 wk resulted in mean (SE) equilibrium whole-body As concentrations of 0.3 (0.02), 0.2 (0.02), 0.4 (0.10), and 1.7 (0.40) μg As∙g wet weight−1, respectively, No depuration below these concentrations occurred during a 12-d period in arsenite-free water. The threshold of chronic toxicity was estimated to be 4.9 mg∙L−1.

Effect of Temperature on Accumulation of Methylmercuric Chloride and p,p′DDT by Rainbow Trout (Salmo gairdneri)

1974 ◽  
Vol 31 (10) ◽  
pp. 1649-1652 ◽  
Author(s):  
Robert E. Reinert ◽  
Linda J. Stone ◽  
Wayne A. Willford
Keyword(s):  
Rainbow Trout ◽  
Water Temperature ◽  
Effect Of Temperature ◽  
Salmo Gairdneri ◽  
Methylmercuric Chloride ◽  
Concentration Factors

Amounts of mercury and DDT residues accumulated from water by yearling rainbow trout (Salmo gairdneri) in the laboratory increased as water temperature increased. Fish exposed to methylmercuric chloride at concentrations of 234–263 parts per trillion for 12 wk at 5, 10, and 15 C accumulated 1.19, 1.71, and 1.96 ppm; fish exposed to p,p′DDT at concentrations of 133–176 parts per trillion accumulated 3.76, 5.93, and 6.82 ppm. Concentrations of mercury accumulated by the fish were significantly different (P < 0.01) at each of the three temperatures, and the concentrations of DDT were significantly different at 5 and 10 and 5 and 15 C. Throughout the period of exposure, the concentration factors (concentration of contaminant in the fish/concentration in water) at each of the three temperatures were far higher for p,p′DDT than for methylmercuric chloride.

scholarly journals Migratory Behaviour of Juvenile Rainbow Trout, Salmo gairdneri, in Outlet and Inlet Streams of Loon Lake, British Columbia

1962 ◽  
Vol 19 (2) ◽  
pp. 201-270 ◽  
Author(s):  
T. G. Northcote
Keyword(s):  
Rainbow Trout ◽  
Water Temperature ◽  
Laboratory Experiments ◽  
Day Length ◽  
Water Current ◽  
Salmo Gairdneri ◽  
Flowing Water ◽  
Juvenile Rainbow Trout ◽  
Outlet Stream ◽  
Downstream Movement

The marked differences in response to water current, exhibited by juvenile rainbow trout migrating into Loon Lake from its outlet and inlet streams, were studied both in the field and in experimental laboratory apparatus. All available evidence argued against genetically discrete outlet and inlet stocks, each maintaining different innate responses to water current. Difference in water temperature between streams was shown, in field and laboratory experiments, to regulate direction of juvenile trout migration through action on behaviour associated with downstream movement, maintenance of position and upstream movement.In laboratory experiments with cool (5 and 10 °C) flowing water, recently emerged fry rarely made contact with the stream bottom in darkness and exhibited much more downstream movement than in warm (> 14 °C) water. In cool streams of the Loon Lake system (daily mean consistently < 13 °C) large numbers of recently emerged fry moved downstream in darkness. Laboratory experiments indicated that combination of cool water (10 °C) and long day length (16 hours) induced downstream movement of fingerlings. In the field, fingerlings moved downstream largely in late spring and summer in cool streams of the Loon Lake system.In laboratory experiments with warm (15 and 20 °C) flowing water, recently emerged fry made frequent contact with the stream bottom in darkness and exhibited much less downstream movement than in cool (10 °C) water. In the warm outlet stream (daily mean in summer usually > 15 °C) recently emerged fry maintained position in darkness. Laboratory experiments suggested that short day length (8 hours) may facilitate maintenance of position exhibited by fingerlings in streams during late autumn and winter.Upstream movement of fry recorded in the field and tested in the laboratory was most pronounced in warm water (> 14 °C). Fingerlings subjected to rapid 5–degree (C) increases in water temperature in an experimental stream exhibited an immediate increase in upstream movement. Upstream movement in summer of large fry and fingerlings occurred only in the warm outlet stream; daily periodicity of upstream movement was positively correlated with sharp rises in water temperature.Evidence examined from four other widely separated stream systems indicated an environmental control of migration in juvenile rainbow trout similar to that demonstrated in the Loon Lake stream system. Possible mechanisms and interaction of factors controlling migratory patterns between and within streams are discussed. Significance of the predominant role played by temperature is considered.

Maximum Tolerable Level, Digestion, and Metabolism of D-Glucose (Cerelose) in Rainbow Trout (Salmo gairdneri) Reared on a Practical Trout Diet

1982 ◽  
Vol 39 (9) ◽  
pp. 1229-1234 ◽  
Author(s):  
J. W. Hilton ◽  
J. L. Atkinson ◽  
S. J. Slinger
Keyword(s):  
Rainbow Trout ◽  
Water Temperature ◽  
Glucose Level ◽  
Energy Content ◽  
Liver Glycogen ◽  
Salmo Gairdneri ◽  
Dietary Energy ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Increased Activity ◽  
Tolerable Level

The maximum tolerable dietary level, digestion, and metabolism of D-glucose (cerelose) were investigated in rainbow trout (Salmo gairdneri) reared on practical diets containing optimum protein and lipid levels at two different water temperatures for 12 wk. Liver glycogen levels (LG) and liver:body weight ratios (LB) initially increased with increasing dietary glucose, but leveled off above 10–15% glucose. The plateauing of LB and LG was consistent with the plateauing of liver glucose-6-phosphate dehydrogenase activity (G6PD) and probably overall hexose monophosphate shunt (HMS) activity at high dietary levels of glucose. This indicates that there may be an optimum ratio of digestible carbohydrate to lipid in salmonid diets. LG and LB tended to be higher in trout reared upon the same dietary glucose level in fish reared at 11 °C as compared with those at 15 °C. This may have been caused by increased activity of the HMS as indicated by increased activity of liver G6PD in fish acclimated to 11 °C as compared to trout reared at 15 °C on the same dietary glucose level (when assayed at 15 °C). The digestion coefficient of glucose was uniformly high (96–99%) and not affected by either dietary glucose level (up to 25% of the diet) or water temperature (11 or 15 °C). The maximum tolerable level of glucose in salmonid diets appears to be dependent upon the protein, lipid, and overall energy content of the diet.Key words: trout, glucose digestion, glucose metabolism, maximum tolerable levels, water temperature, dietary energy

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