Gill Irrigation and Pressure Relationships in Rainbow Trout (Salmo gairdneri)

1973 ◽  
Vol 30 (1) ◽  
pp. 99-104 ◽  
Author(s):  
John C. Davis ◽  
David J. Randall
Keyword(s):  
Rainbow Trout ◽  
Oxygen Uptake ◽  
Dead Space ◽  
Ventilation Rate ◽  
Differential Pressure ◽  
Salmo Gairdneri ◽  
Oxygen Cost ◽  
Low Area ◽  
Anatomical Dead Space ◽  
Marked Decline

In studies on 11 rainbow trout (Salmo gairdneri), 217.3 ± 6.5 g, 14.0 ± 0.5 C) fitted with rubber membranes for direct measurement of ventilatory water flow [Formula: see text], buccal, cleithral, and differential pressure traces increased in amptitude as [Formula: see text] rose from 40 to 160 ml/min. Ventilation rate remained steady at around 77 breaths/min in the [Formula: see text] range 40–120 ml/min and rose to 90 breaths/min at a [Formula: see text] of 175 ml/min. Oxygen uptake more than doubled as [Formula: see text] rose from 40 to 120 ml/min. Calculated utilization of oxygen from the inspired water declined only slightly over this [Formula: see text] range, indicating that large increases in nonrespiratory spillage of water (anatomical dead space) had not occurred. The calculated oxygen cost of breathing was low. Area mean differential pressure appeared closely related to [Formula: see text] over the [Formula: see text] range 40–160 ml/min. Area mean differential pressure increased from two- to four fold over this [Formula: see text] range, depending upon which individual fish was examined. Over the [Formula: see text] range 40–160 ml/min the calculated resistance of the gill sieve did not appear to decline although some variability was present and a variety of gill sieve resistances could be measured at a given [Formula: see text] for each fish. It is concluded that changes in [Formula: see text] are largely dependent on changes in mean differential pressures across the gills, with no marked decline in gill sieve resistance over the normal physiological range of [Formula: see text].

Responses of the Respiratory Pumps to Hypoxia in the Rainbow Trout (Salmo Gairdneri)

1970 ◽  
Vol 53 (3) ◽  
pp. 529-545 ◽  
Author(s):  
G. M. HUGHES ◽  
R. L. SUNDERS
Keyword(s):  
Oxygen Consumption ◽  
Rainbow Trout ◽  
Stroke Volume ◽  
Minute Volume ◽  
Differential Pressure ◽  
Salmo Gairdneri ◽  
Oxygen Cost ◽  
Volume Measurements ◽  
Overall Efficiency ◽  
Work Done

1. Unanaesthetized rainbow trout, when subjected to a lowered Po2 of the inspired water, show an increase in amplitude of pressures recorded from the buccal and opercular cavities. Pressure amplitudes were commonly found to be 0.5 cm of water in resting trout and increased 4- or 5-fold as inspired Po2 was reduced. Differential pressures across the gills also increased with hypoxia. 2. Typically the minute volume in a 400-600 g trout increased from about 0.2 to 0.6 l/kg/min when the inspired Po2 was lowered from 150 to 80 mm Hg, but rose to 1-5l/kg/min at lower Po2. Increased minute volumes are mainly due to increases in stroke volume; respiratory frequency remains fairly constant at Po2 's above about 8o mm Hg. 3. The relation between differential pressure and minute volume is fairly linear over much of the range, but minute volume increases more rapidly than differential pressure. 4. Oxygen consumption of the non-swimming fish increases during hypoxia and is related to the increased ventilation and differential pressure across the gills. 5. Estimates of the oxygen cost of breathing were made from the increased oxygen consumption during hyperventilation. Comparison of these estimates with estimates of the work done, using the pressure and volume measurements, gave figures for the overall efficiency of the pumping mechanism of about 10%.

Cardiovascular changes in the rainbow trout (Salmo gairdneri Richardson) during exercise

1982 ◽  
Vol 60 (5) ◽  
pp. 1135-1140 ◽  
Author(s):  
D. J. Randall ◽  
C. Daxboeck
Keyword(s):  
Blood Flow ◽  
Rainbow Trout ◽  
Oxygen Uptake ◽  
Flow Distribution ◽  
Distribution Patterns ◽  
Systemic Circulation ◽  
Salmo Gairdneri ◽  
Systemic Blood Flow ◽  
Blood Flow Control ◽  
Underlying Mechanisms

The effects of steady-state, aerobic swimming exercise upon the cardiovascular system of rainbow trout (Salmo gairdneri) are discussed. When these fish are forced to swim at 80% of their critical velocity, blood flow is redistributed in the systemic circulation to favour working muscles, at the expense of decreased flow to nonmuscle structures. Given oxygen uptake and cardiac output data, combined with blood flow distribution patterns during exercise, it is calculated that the working muscles can account for nearly all the measured increase in total oxygen uptake at this level of exercise. The possible underlying mechanisms for systemic blood flow control and the increase in gas exchange efficiency across the gills of exercising rainbow trout also are examined.

Water Flow and Gas Exchange at the Gills of Rainbow Trout, Salmo Gairdneri

1971 ◽  
Vol 54 (1) ◽  
pp. 1-18 ◽  
Author(s):  
JOHN C. DAVIS ◽  
JAMES N. CAMERON
Keyword(s):  
Rainbow Trout ◽  
Gas Exchange ◽  
Stroke Volume ◽  
Water Flow ◽  
Ventilation Rate ◽  
Salmo Gairdneri ◽  
Perfusion Rate ◽  
Rubber Membrane ◽  
Flow Rates ◽  
Arterial Blood

1. Ventilation volume was measured directly in rainbow trout using a rubber membrane attached to the mouth which separated inspired and expired water and allowed collection of the latter. 2. Mean ventilation volume at 8.6 °C for 18 trout weighing approximately 200 g was 37±1.8 ml/min/fish. Mean ventilation rate and ventilatory stroke volume averaged 74 breaths/min and 0.5 ml/breath respectively. 3. Ventilation volume could be increased nearly sevenfold during moderate, shortterm hypoxia as a result of a large increase in ventilatory stroke volume and a small increase in ventilation rate. 4. The ratio between the flow rates of water and blood through the gills was approximately 10. 5. Percentage utilization of oxygen from inspired water had a mean of 46±1.5% and ranged from 23 to 64%. 6. Artificial perfusion of the gills with water at different flow rates was achieved by tying a tube into the mouth of trout. 7. Perfused fish could not saturate their arterial blood with oxygen at a perfusion rate of 45 ml/min but could do so at rates ranging from 85 to 1200 ml/min. 8. Low arterial tensions at a perfusion rate approximating the mean V·G of fish with oral membranes are probably the result of a poor pattern of water flow over the gills during perfusion. 9. Opercular movements occurred only at perfusion rates below 700 ml/min and increased in frequency as perfusion rate dropped. This ventilatory activity may have resulted from receptors sensitive either to water flow over the gills or to arterial Po2. 10. As perfusion rate went up cardiac output and oxygen uptake increased. These changes were accompanied by a drop in dorsal aortic pressure which reflected vasodilation of the gills and peripheral circulation. This change in the pattern of blood flow through the gills contributed to a 50% increase in oxygen transfer factor across the gills. 11. At the highest perfusion rates there was no apparent impairment of gas exchange even though anatomical deadspace was probably high.

The Exchange of Oxygen and Carbon Dioxide Across the Gills of Rainbow Trout

1967 ◽  
Vol 46 (2) ◽  
pp. 339-348 ◽  
Author(s):  
D. J. RANDALL ◽  
G. F. HOLETON ◽  
E. DON STEVENS
Keyword(s):  
Carbon Dioxide ◽  
Rainbow Trout ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Transfer Factor ◽  
Rate Ratio ◽  
High Capacity ◽  
Salmo Gairdneri ◽  
Moderate Exercise ◽  
Carbon Dioxide Uptake

1. The effectiveness of oxygen uptake by the blood of rainbow trout (Salmo gairdneri) approaches 100%, whereas that for the removal of oxygen from water was only 11-30%. 2. Most of the carbon dioxide is removed from the blood as it passes through the gills, but the effectiveness of carbon dioxide uptake by water is very low, because of the high capacity of water for carbon dioxide compared with oxygen. 3. Moderate exercise had little effect on the effectiveness of gas exchange across the gills. The increased oxygen uptake was facilitated by an increase in the transfer factor of the gills for oxygen. There were small increases in the capacity-rate ratio of blood to water at the gills during moderate exercise. 4. Hypoxia resulted in a marked decrease in the effectiveness of oxygen uptake by the blood, but had little effect on oxygen removal from the water. Gas exchange was facilitated during hypoxia by an increase in transfer factor of the gills, but hindered by an increasing capacity-rate ratio of blood to water at the gills. 5. Gas exchange in an aquatic environment was compared with that in an aerial environment.

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