Uptake of Waterborne Methylmercury by Rainbow Trout (Salmo gairdneri) in Relation to Oxygen Consumption and Methylmercury Concentration

1981 ◽  
Vol 38 (11) ◽  
pp. 1309-1315 ◽  
Author(s):  
D. W. Rodgers ◽  
F. W. H. Beamish

Oxygen consumption and uptake of waterborne methylmercury were measured for rainbow trout (Salmo gairdneri) forced to swim at sustained swimming speeds at 10 and 20 °C. The concentrations of methylmercury used (< 8 μg Hg∙L−1) did not affect oxygen consumption. The log of mass specific oxygen consumption increased linearly with relative swimming speed. Standard metabolic rates were significantly different (P < 0.05) at 10 and 20 °C (111 and 192 mg O2∙kg−1∙h−1, respectively) but the rate of increase in oxygen consumption with swimming speed was not significantly different between temperatures. The rate of methylmercury uptake was positively correlated with both oxygen consumption and methylmercury concentration. Multiple linear regression equations relating the logs of rate of methylmercury uptake, rate of oxygen consumption, and methylmercury concentration at 10 and 20 °C were contiguous and a single equation described the relationship at both temperatures. The efficiency of methylmercury uptake relative to oxygen was ~0.25 at both temperatures. Assuming an oxygen percent utilization of 33%, the percent utilization of methylmercury from water was ~8%.Key words: methylmercury, uptake, respiration, oxygen consumption, rainbow trout, bioaccumulation, pollutant

2001 ◽  
Vol 204 (12) ◽  
pp. 2133-2144 ◽  
Author(s):  
G. Froget ◽  
P. J. Butler ◽  
Y. Handrich ◽  
A. J. Woakes

SUMMARY The use of heart rate to estimate field metabolic rate has become a more widely used technique. However, this method also has some limitations, among which is the possible impact that several variables such as sex, body condition (i.e. body fat stores) and/or inactivity might have on the relationship between heart rate and rate of oxygen consumption. In the present study, we investigate the extent to which body condition can affect the use of heart rate as an indicator of the rate of oxygen consumption. Twenty-two breeding king penguins (Aptenodytes patagonicus) were exercised on a variable-speed treadmill. These birds were allocated to four groups according to their sex and whether or not they had been fasting. Linear regression equations were used to describe the relationship between heart rate and the rate of oxygen consumption for each group. There were significant differences between the regression equations for the four groups. Good relationships were obtained between resting and active oxygen pulses and an index of the body condition of the birds. Validation experiments on six courting king penguins showed that the use of a combination of resting oxygen pulse and active oxygen pulse gave the best estimate of the rate of oxygen consumption V̇O2. The mean percentage error between predicted and measured V̇O2 was only +0.81% for the six birds. We conclude that heart rate can be used to estimate rate of oxygen consumption in free-ranging king penguins even over a small time scale (30min). However, (i) the type of activity of the bird must be known and (ii) the body condition of the bird must be accurately determined. More investigations on the impact of fasting and/or inactivity on this relationship are required to refine these estimates further.


1998 ◽  
Vol 201 (19) ◽  
pp. 2779-2789 ◽  
Author(s):  
DM Webber ◽  
RG Boutilier ◽  
SR Kerr

Adult Atlantic cod (2 kg Gadus morhua) were fitted with Doppler ultrasonic flow-probes to measure ventral aortic outflow (i.e. cardiac output). The probes remained patent for upwards of 3 months, during which time detailed relationships between cardiac output (), heart rate (fh) and rate of oxygen consumption (O2) were determined as a function of swimming speed and temperature (5 degreesC and 10 degreesC). The rate of oxygen consumption increased linearly with and exponentially with swimming speed. A very good correlation was observed between O2 and (r2=0.86) compared with the correlation between O2 and fh (r2=0.50 for all 10 degreesC data and r2=0.86 for all 5 degreesC data). However, the O2 versus fh correlation gradually improved over approximately 1 week after surgery (r2=0.86). The relationship between O2 and was independent of temperature, while the relationship between O2 and fh changed with temperature. Hence, calculating O2 from is simpler and does not require that temperature be recorded simultaneously. Variations in cardiac output were determined more by changes in stroke volume (Vs) than by fh; therefore, fh was a less reliable predictor of metabolic rate than was . Given that can be used to estimate O2 so faithfully, the advent of a cardiac output telemeter would enable robust estimates to be made of the activity metabolism of free-ranging fish in nature, thereby strengthening one of the weakest links in the bioenergetic models of fisheries biology.


2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 218-219
Author(s):  
Andres Fernando T Russi ◽  
Mike D Tokach ◽  
Jason C Woodworth ◽  
Joel M DeRouchey ◽  
Robert D Goodband ◽  
...  

Abstract The swine industry has been constantly evolving to select animals with improved performance traits and to minimize variation in body weight (BW) in order to meet packer specifications. Therefore, understanding variation presents an opportunity for producers to find strategies that could help reduce, manage, or deal with variation of pigs in a barn. A systematic review and meta-analysis was conducted by collecting data from multiple studies and available data sets in order to develop prediction equations for coefficient of variation (CV) and standard deviation (SD) as a function of BW. Information regarding BW variation from 16 papers was recorded to provide approximately 204 data points. Together, these data included 117,268 individually weighed pigs with a sample size that ranged from 104 to 4,108 pigs. A random-effects model with study used as a random effect was developed. Observations were weighted using sample size as an estimate for precision on the analysis, where larger data sets accounted for increased accuracy in the model. Regression equations were developed using the nlme package of R to determine the relationship between BW and its variation. Polynomial regression analysis was conducted separately for each variation measurement. When CV was reported in the data set, SD was calculated and vice versa. The resulting prediction equations were: CV (%) = 20.04 – 0.135 × (BW) + 0.00043 × (BW)2, R2=0.79; SD = 0.41 + 0.150 × (BW) - 0.00041 × (BW)2, R2 = 0.95. These equations suggest that there is evidence for a decreasing quadratic relationship between mean CV of a population and BW of pigs whereby the rate of decrease is smaller as mean pig BW increases from birth to market. Conversely, the rate of increase of SD of a population of pigs is smaller as mean pig BW increases from birth to market.


Author(s):  
R. C. Newell ◽  
H. R. Northcroft

The rate of cirral beat of Balanus balanoides is related to the logarithm of the body weight as an exponential function. In any one animal, there is little effect of temperature on cirral activity between 7·5° and 10° C. Between 10° and 20° C, however, there is a rapid increase in cirral beat with temperature followed by a fall at temperatures above 20° C.Balanus balanoides exhibits a fast, medium and zero rate of oxygen consumption. These rates of oxygen consumption correspond with (a) normal cirral beating, (b) ‘testing’ activity with no cirral movement, and (c) with the closure of the mantle cavity. Both of the possible levels of oxygen uptake are related to the logarithm of the body weight in a logarithmic fashion over the temperature range 7·5°–22·5° C. Temperature affects the two rates of oxygen consumption differently. In the slower rate (rate B) there is an increase in the rate of oxygen consumption between 7·5° and 14° C but there is no significant increase in the rate of oxygen consumption between 14° and 22·5 C°.


1973 ◽  
Vol 59 (1) ◽  
pp. 255-266
Author(s):  
H. J. ATKINSON

1. The rate of oxygen consumption of individual males of Enoplus brevis and E. communis was measured at 15 °C and at each of four oxygen tensions, 135, 75, 35, and 12 Torr, after at least 12 h experience of these conditions. 2. It was clearly demonstrated that the level of oxygen consumption of both species was reduced by each lowering of the imposed oxygen tension. 3. In all cases the oxygen consumption of each species fell with increasing body size. On a unit dry-weight basis the oxygen consumption of E. brevis is greater than that of the larger E. communis, but after allowing for the difference of body size the two species have more or less similar oxygen uptakes at all oxygen tensions. 4. In E. brevis oxygen tension influenced the relationship of body size and metabolism, the slope relating oxygen consumption and body weight becomes steeper with decreasing oxygen tension. This effect was not shown by E. communis. 5. Some general factors influencing the availability of oxygen to nematodes are considered.


1971 ◽  
Vol 55 (2) ◽  
pp. 521-540 ◽  
Author(s):  
P. W. WEBB

1. The oxygen consumption of rainbow trout was measured at a variety of subfatigue swimming speeds, at a temperature of 15 %C. Five groups of fish were used, a control group and four groups with extra drag loads attached to the body. 2. The logarithm of oxygen consumption was linearly related to swimming speed in all five groups, the slope of the relationship increasing with the size of the extra drag load. The mean standard rate of oxygen consumption was 72.5 mg O2/kg wet weight/h. The active rate of oxygen consumption was highest for the control group (628 mg O2/kg/h) and fell with increasing size of the attached drag load. The active rate for the control group was high in comparison with other salmonid fish, and in comparison with the value expected for the fish. This was not a result of the extra drag loads in the other groups. No explanation for this high value can be found. 3. The critical swimming speed for a 60 min test period was 58.1 cm/sec (2.0 body lengths/sec) for the control group. The values for the critical swimming speeds were slightly higher than those measured for the same species in a previous paper (Webb, 1971). The difference between the two sets of critical swimming speeds is attributed to seasonal changes in swimming performance. 4. The aerobic efficiency was found to reach values of 14.5-15.5% based on the energy released by aerobic metabolism in comparison with the calculated required thrust. 5. The anaerobic contribution to the total energy budget in increasing-velocity tests is considered to be small, and can be neglected. 6. It is concluded that the efficiency of the muscle system in cruising will be approximately 17-20% over the upper 80% of the cruising-speed range, while the caudal propeller efficiency will increase from about 15-75 % over the same range. 7. Consideration of the efficiency values for the caudal propeller calculated here, and those predicted by Lighthill's (1969) model of fish propulsion, suggest that the efficiency of the propeller system will reach an optimum value at the maximum cruising speeds of most fish, and will remain close to this value at spring speeds.


2002 ◽  
Vol 205 (16) ◽  
pp. 2511-2517 ◽  
Author(s):  
G. Froget ◽  
Y. Handrich ◽  
Y. Le Maho ◽  
J.-L. Rouanet ◽  
A. J. Woakes ◽  
...  

SUMMARY This study investigated whether exposure to low ambient temperature could be used as an alternative to exercise for calibrating heart rate (fH)against rate of oxygen consumption(V̇O2) for subsequent use of fH to estimate V̇O2 in free-ranging animals. Using the relationship between the oxygen pulse (OP, the amount of oxygen used per heart beat) and an index of body condition (or nutritional index, NI), a relationship between fH and V̇O2 was established for resting king penguins exposed to a variety of environmental temperatures. Although there was a small but significant increase in the OP above and below the lower critical temperature (-4.9°C), there was no difference in the relationship obtained between the OP and body condition (NI)obtained above or below the lower critical temperature. These results were then compared with those obtained in a previous study in which the relationship between fH and V̇O2 had been established for king penguins during steady-state exercise. The relationship between OP and NI in the present study was not significantly different from the relationship between resting OP and NI in the previous study. However, the relationship was different from that between active OP and NI. We conclude that, at least for king penguins, although thermoregulation does not affect the relationship between resting OP and NI, temperature cannot be used as an alternative to exercise for calibrating fH against V̇O2 for subsequent use of fH to estimate V̇O2 in free-ranging animals.


1972 ◽  
Vol 59 (1) ◽  
pp. 60-76 ◽  
Author(s):  
F. L. Vieira ◽  
S. R. Caplan ◽  
A. Essig

Sodium transport and oxygen consumption were studied simultaneously in the short-circuited frog skin. Sodium transport was evaluated from Io/F, where Io is the short-circuit current measured with standard Ringer's solution bathing each surface and F is the Faraday constant. Oxygen tension was measured polarographically. Under a variety of circumstances the rate of oxygen consumption from the outer solution exceeded that from the inner solution, the ratio being constant (0.57 ± 0.09 SD). Both Io and the associated rate of oxygen consumption Jro declined nonlinearly with time, but the relationship between them was linear, suggesting that the basal oxygen consumption was constant. For each skin numerous experimental points were fitted by the best straight line. The intercept (Jro)Io=0 then gave the basal oxygen consumption, and the slope dNa/dO2 gave an apparent stoichiometric ratio for a given skin. The basal oxygen consumption was about one-half the total oxygen consumption in a representative untreated short-circuited skin. Values of dNa/dO2 in 10 skins varied significantly, ranging from 7.1 to 30.9 (as compared with Zerahn's and Leaf and Renshaw's values of about 18). KCN abolished both Io and Jro. 2,4-dinitrophenol (DNP) depressed Io while increasing Jro four- to fivefold. Anti-diuretic hormone stimulated and ouabain depressed both Io and Jro; in both cases apparent stoichiometric ratios were preserved.


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