Copper metabolism and gut morphology in rainbow trout (Oncorhynchus mykiss) during chronic sublethal dietary copper exposure

2001 ◽  
Vol 58 (2) ◽  
pp. 293-305 ◽  
Author(s):  
Collins N Kamunde ◽  
Martin Grosell ◽  
John NA Lott ◽  
Chris M Wood
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Granule Cells ◽  
Copper Metabolism ◽  
Exposure Period ◽  
Whole Body ◽  
Electron Microscopic ◽  
Dietary Copper ◽  
Cu Content ◽  
Rainbow Trout Oncorhynchus Mykiss

Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to 11 (control), 300 (medium), and 1000 µg Cu·g–1 (high) (as CuSO4·5H2O) in the diet for 28 days at a daily ration of 4% wet body weight, with a background waterborne Cu concentration of 3 µg·L–1. There was no effect of dietary Cu on growth, condition factor, or food conversion efficiency. Whole-body Cu content increased continuously over the exposure period in all groups and was twofold and fourfold higher than controls at day 28 for the medium- and high-Cu diets, respectively. Copper accumulated mainly in liver and gut tissue, with the latter stabilizing by day 14. Accumulation also occurred in gill, kidney, and carcass. Plasma Cu concentration was not different from the controls whereas Cu in bile was greatly elevated, an indication of increased hepatobiliary excretion. Dietary Cu pre-exposure decreased the uptake of waterborne Cu across the gills, providing the first evidence of homeostatic interaction between the two routes of uptake. Electron microscopic observations of the midintestine revealed numerous mitochondria, lysosomes, lamellated bodies, and extensive lamellar processes in the enterocytes. Apoptosis, mitosis, and eosinophilic granule cells were more apparent in Cu-exposed fish.

Effects of different ligands on the bioaccumulation and subsequent depuration of dietary Cu and Zn in juvenile rainbow trout (Oncorhynchus mykiss)

2006 ◽  
Vol 63 (2) ◽  
pp. 412-422 ◽  
Author(s):  
Victoria A Kjoss ◽  
Chris M Wood ◽  
D Gordon McDonald
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Metal Accumulation ◽  
Whole Body ◽  
Control Fish ◽  
Dietary Copper ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Control Food ◽  
Cu And Zn

The effects of different ligands on the bioavailability of dietary copper (Cu) and zinc (Zn) to fish have not been thoroughly investigated. We therefore exposed juvenile rainbow trout (Oncorhynchus mykiss; ~200 mg body weight) to control food or to food supplemented with different Cu (~400 µg·g–1 food) or Zn (~1000 µg·g–1 food) compounds. Tissue metal accumulation was compared among groups. Fish fed CuO showed no differences in tissue Cu concentrations relative to control fish, suggesting that Cu was not readily available for uptake in this form. In contrast, Cu in the form of CuSO4, Cu-proteinate, or Cu-lysine was much more available for uptake, resulting in substantial increases in liver, gut tissue, and whole-body Cu concentrations during the loading phase and decreases during depuration, although liver and whole-body levels remained elevated after 2 weeks. We found no differences in tissue Cu accumulation among these three complexes. There were no effects on growth. For Zn, we found no differences among any of the treatments, including controls, in Zn accumulation or growth. Overall, there was homeostasis of whole-body and tissue-specific Zn concentrations despite the large differences in dietary Zn loads.

Copper metabolism in actively growing rainbow trout (Oncorhynchus mykiss): interactions between dietary and waterborne copper uptake

2002 ◽  
Vol 205 (2) ◽  
pp. 279-290
Author(s):  
Collins Kamunde ◽  
Martin Grosell ◽  
Dave Higgs ◽  
Chris M. Wood
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Copper Metabolism ◽  
Fold Increase ◽  
Linear Increase ◽  
Whole Body ◽  
Absolute Amount ◽  
Nutritional Requirement ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Cu Uptake

SUMMARY Juvenile rainbow trout Oncorhynchus mykiss were exposed to diets with low (12.6 nmol g–1), normal (50.4 nmol g–1) or elevated (4437.5 nmol g–1) Cu concentrations in combination with either low (5.8 nmol l–1) or normal (48.5 nmol l–1) waterborne Cu levels over a 50-day period, during which body mass increased up to fivefold. A nutritional requirement for Cu was demonstrated based on growth response and whole body and tissue Cu status. Simultaneous low Cu levels in both the water and the diet depressed growth by 31 % over 7 weeks. There were reductions in both specific growth rate (SGR, 1.95 versus 2.55 % day–1) and food conversion efficiency (FCE, 53–59 % versus 75–80 %) over weeks 0–4, but these effects disappeared in weeks 4–7. Elevated concentrations of dietary Cu did not affect SGR or FCE. Low levels of dietary and waterborne Cu decreased, and high levels of dietary Cu increased, the Cu concentrations in whole body, liver, carcass, gut and gills. Copper levels in the liver strongly reflected the exposure conditions with a corresponding fivefold decrease and a 22-fold increase in Cu concentration. Restricting available Cu caused an exponential decline in whole body Cu concentration from 0.0175 to 0.0069 μmol g–1 and increased the uptake of waterborne Cu (measured with 64Cu) by the gills. Conversely, high levels of dietary Cu caused a linear increase in whole body Cu concentration to approximately 0.170 μmol g–1 and depressed the uptake of waterborne Cu. Waterborne Cu uptake contributed the majority (60 %) of the body’s Cu accumulation under Cu-deficient conditions while dietary Cu contributed the majority (99 %) at high dietary levels of Cu. True bioavailability of dietary Cu decreased with increasing levels of dietary Cu concentration, although the absolute amount retained increased. These findings demonstrate an important interaction between dietary and waterborne Cu uptake in fish and provide compelling evidence of a key role for the gill in Cu homeostasis.

Composition and Mechanics of Routine Swimming of Rainbow Trout, Oncorhynchus mykiss

1991 ◽  
Vol 48 (4) ◽  
pp. 583-590 ◽  
Author(s):  
Paul W. Webb
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Correction Factor ◽  
Swimming Speed ◽  
Angular Acceleration ◽  
Force Balance ◽  
Whole Body ◽  
Strongly Correlated ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Tail Beat

Routine swimming encompasses all volitional motions of fish. It is usually assumed to be quasi-steady, i.e. routine swimming is mechanically equivalent to steady swimming. Routine swimming of rainbow trout, Oncorhynchus mykiss, was dominated by unsteady motions of linear and centripetal (angular) acceleration. Constant-speed swimming was rare. Mean speeds and acceleration rates were small. Tail-beat frequencies were nevertheless strongly correlated with mean swimming speed, but increased more rapidly with increasing speed in routine swimming than in steady swimming. Tail-beat amplitudes and propulsive wavelengths were similar to values seen in steady swimming. The composition of routine swimming and analysis of the force balance showed that routine swimming was not quasi-steady. Therefore, forces and rates of working should be estimated from a complete description of whole-body deformation. This is impractical. Drag dominated resistance in routine swimming, such that average thrust (= resistance) may be computed from mean speed and/or averaged kinematic variables for the trailing edge with a correction factor of approximately 3. Analysis of routine swimming may permit comparisons among a wider range of vertebrates than possible with commonly used methods.

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.

Diminished social status affects ionoregulation at the gills and kidney in rainbow trout (Oncorhynchus mykiss)

2004 ◽  
Vol 61 (4) ◽  
pp. 618-626 ◽  
Author(s):  
Katherine A Sloman ◽  
Graham R Scott ◽  
D Gordon McDonald ◽  
Chris M Wood
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Social Status ◽  
Metabolic Cost ◽  
Whole Body ◽  
Sodium Reabsorption ◽  
Plasma Sodium ◽  
Sodium Efflux ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Uptake Rates

Competition for social status can result in physiological differences between individuals, including differences in ionoregulatory ability. Subordinate rainbow trout (Oncorhynchus mykiss) had two-fold higher uptake rates of sodium across the gill and two-fold higher whole-body sodium efflux rates than the dominant fish with which they were paired. Sodium efflux was then divided into branchial and renal components, both of which were higher in subordinates. Branchial sodium efflux accounted for 95%–98% of sodium loss. Plasma sodium concentrations were more variable, although not significantly different, in subordinate fish, suggesting that the increased loss of sodium in these trout is compensated for by an increase in uptake rates. Urine flow rates and plasma cortisol concentrations were higher in subordinate fish, but there was no difference in glomerular filtration rate between dominants and subordinates. Renal sodium reabsorption was significantly reduced in subordinates. In summary, the ionoregulation of subordinate individuals was altered, most likely occurring as a result of stress-induced changes in gill permeability, resulting in a higher throughput of water and increased branchial sodium efflux. These changes in ionoregulatory ability have many physiological implications, including the increased susceptibility of subordinates to ionoregulatory challenges and an increased metabolic cost of ionoregulation.

Conspecific skin extracts elicit antipredator responses in juvenile rainbow trout (Oncorhynchus mykiss)

1997 ◽  
Vol 75 (11) ◽  
pp. 1916-1922 ◽  
Author(s):  
Grant E. Brown ◽  
R. Jan F. Smith
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Whole Body ◽  
Antipredator Behaviour ◽  
Skin Extract ◽  
Distilled Water ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Antipredator Responses ◽  
Body Extract

We investigated, under laboratory conditions, the presence of chemical alarm signals in juvenile rainbow trout (Oncorhynchus mykiss). In an initial experiment, we exposed trout to a whole-body extract from conspecifics or a distilled-water control. When exposed to whole-body extract, trout significantly (i) decreased time spent swimming, (ii) increased time taken to resume foraging, and (iii) decreased the number of food items eaten. These data indicate a significant chemically mediated antipredator response. A second experiment was conducted to determine (i) if this is a generalized response to injured fish or a specific response to injured conspecifics, and (ii) if the chemical signal is localized in the skin. We exposed juvenile trout to one of three chemical stimuli: (1) trout skin extract, (2) trout body extract, or (3) swordtail (Xiphophorus helleri) skin extract. Significant antipredator responses were observed in trout exposed to conspecific skin extract, but responses of those exposed to conspecific body extract or swordtail skin extract did not differ from those of distilled-water controls. These data strongly suggest that juvenile rainbow trout possess a chemical alarm signal, localized in the skin, that elicits antipredator behaviour when detected.by conspecifics.

Sign in / Sign up

Export Citation Format

Share Document