In situ activity metabolism of rainbow trout (Oncorhynchus mykiss): estimates obtained from telemetry of axial muscle electromyograms

1997 ◽  
Vol 54 (4) ◽  
pp. 859-866 ◽  
Author(s):  
C T Briggs ◽  
J R Post

Activity metabolism of free-swimming rainbow trout (Oncorhynchus mykiss) was estimated using electromyogram telemetry of the axial muscle. Estimates were obtained for five fish for temperatures ranging from 3 to 22°C. Activity metabolism was divided by standard metabolism to produce a relative metabolic cost of activity (RMA). The average diel pattern of RMA was predominantly crepuscular. RMA increased at dawn and then slowly increased to an average maximum peak of 1.8 at dusk. After dusk, RMA slowly declined to a minimum value of 1.4 just prior to dawn. The diel pattern was similar over most of the temperature range studied, but became less distinct at the upper and lower limits of the range. Changes in mean daily RMA were strongly correlated with changes in mean temperature. Mean RMA of the five fish sampled over three seasons was 1.5, with very little variation among fish. The results of this study indicate that the activity metabolism of free-swimming rainbow trout is less than twice standard.

1991 ◽  
Vol 48 (4) ◽  
pp. 583-590 ◽  
Author(s):  
Paul W. Webb

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.


2004 ◽  
Vol 61 (4) ◽  
pp. 618-626 ◽  
Author(s):  
Katherine A Sloman ◽  
Graham R Scott ◽  
D Gordon McDonald ◽  
Chris M Wood

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.


2002 ◽  
Vol 59 (5) ◽  
pp. 768-777 ◽  
Author(s):  
H A Campbell ◽  
R D Handy ◽  
D W Sims

This study tests the hypothesis that rainbow trout (Oncorhynchus mykiss) compensate for the metabolic cost of dietary Cu exposure by reducing swimming activity at particular times during the diel cycle. Fish were exposed to excess dietary Cu for three months (726 mg Cu·kg–1 dry weight) and simultaneously oxygen consumption (MO2) and spontaneous swimming activity were measured. Rhythmicity in swimming activity was examined by videorecording fish behaviours for 48 h. Standard metabolic rate estimates (RS) of 7.2 and 8.7 mmol O2·kg–1·h–1 (15°C) were measured for control and Cu-exposed fish, respectively. MO2 was higher in Cu-exposed fish at any chosen speed compared with control Cu-exposed trout, which decreased activity (mean speed) by at least 75%, spent more time at lower speeds, and lost circadian periodicity in these parameters compared with controls. Mean growth rates were normal, although Cu-exposed fish showed a narrower range of body weights and fewer mortalities than control groups, suggesting a suppression in social behaviour in Cu-exposed fish. Overall, the increased metabolic cost of swimming in Cu-exposed fish was fully compensated by a reduction in activity, particularly at night and dawn. However, this behavioural strategy suggests that spatial and temporal aspects of ecologically important social behaviours may be compromised in Cu-exposed fish.


2006 ◽  
Vol 63 (6) ◽  
pp. 1405-1413 ◽  
Author(s):  
Marcie M Ninness ◽  
E Don Stevens ◽  
Patricia A Wright

The objective of our study was to estimate the overall (aerobic and anaerobic) energy expenditure involved in hatching in rainbow trout (Oncorhynchus mykiss) embryos. During hatching, there were significant increases (50% and 19%, respectively) in movement and oxygen consumption. There were no differences in tissue indicators of anaerobic metabolism (adenosine triphosphate (ATP), adenosine monophosphate (AMP) deaminase, ammonia) between embryos that hatched naturally (chorionated) compared with embryos in which the chorion had been manually removed and therefore did not hatch (dechorionated). Furthermore, phosphocreatine (PCr), ATP, and lactate were unaltered immediately after hatching compared with embryos at rest before hatch. The anaerobic capacity of just hatched larvae was further evaluated by forced exercise and hypoxic exposure. PCr and ATP were unaltered following a 2 min manual chase, whereas lactate concentration was significantly increased (30%). Hypoxia (5 mg O2·L–1, 5 days) resulted in a 2.7-fold elevation of tissue lactate concentration. Our results reveal that the increase in activity during hatch may be involved in escaping the egg capsule, but the metabolic cost of this increased movement is relatively small. Moreover, the anaerobic capacity of newly hatched rainbow trout is low relative to juvenile or adult fish.


Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
A Ghasemi Pirbalouti ◽  
E Pirali ◽  
G Pishkar ◽  
S Mohammadali Jalali ◽  
M Reyesi ◽  
...  

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