DOI•
A study of the cardiovascular system of the rainbow trout (Salmo gairdneri) at rest and during swimming exercise
01 Jan 1981-
About: The article was published on 1981-01-01 and is currently open access. It has received 11 citations till now. The article focuses on the topics: Rainbow trout & Salmo.
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TL;DR: By increasing Hct and thereby maintaining oxygen delivery to the intestines, the HS group maintained normal intestinal function while swimming at the higher velocity, enabling overall growth rate to be the same as in the LS group.
Abstract: Blood flow in the intestinal artery (qia), the rate of oxygen consumption (V(dot)O2) and a number of haematological variables were measured in chinook salmon, Oncorhynchus tshawytscha, while they swam up to the critical swimming velocity (Ucrit). The fish used in this study had previously been exposed to one of two different exercise-training regimes, swimming for 8 months at either 1.5 bl s-1 (HS) or 0.5 bl s-1 (LS) (where bl is body length). During this period, growth rate was the same in both groups. At rest, qia was approximately 36 % of cardiac output. qia was inversely related to V(dot)O2, indicating that blood flow was gradually redistributed from the viscera as the oxygen demands of the locomotory muscles increased. Both V(dot)O2 and qia were relatively constant at swimming velocities less than 50 % Ucrit, but at Ucrit, qia had decreased by 60–70 % as V(dot)O2 reached a maximum. Blood flow redistribution away from the intestine contributed significantly to the oxygen supply for locomotory muscles, since it was estimated that the oxygen-transporting capacity of this redistributed blood flow was enough to support 12–18 % of the maximum internal oxygen consumption (total V(dot)O2 - gill V(dot)O2). Following exercise training, haematocrit (Hct) in the HS group (27.1 %) was significantly higher than in the LS group (23.3 %). However, neither the maximum V(dot)O2 nor Ucrit was significantly different in the two groups. qia was inversely related to Hct but, in spite of lower qia at rest, oxygen transport to the intestines was greater at all swimming speeds in the HS than in the LS training group. In addition, blood flow in the HS group was better maintained as the swimming speed was increased. As a result of the higher Hct in the HS-trained group, oxygen transport to the intestines was similar in both groups at their respective training velocities. Therefore, we suggest that, by increasing Hct and thereby maintaining oxygen delivery to the intestines, the HS group maintained normal intestinal function while swimming at the higher velocity, enabling overall growth rate to be the same as in the LS group.
155 citations
Cites background from "A study of the cardiovascular syste..."
...Direct measurements of gastrointestinal blood flow appear to indicate consistently that a higher proportion of cardiac output goes to the gut than the 10–20% estimated using radiolabelled microspheres (Daxboeck, 1981; Barron et al. 1987; H. Thorarensen, unpublished observations)....
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TL;DR: During hypoxia, an adrenergic control of the gastrointestinal vasculature with both nervous and humoral components was found, whereas during exercise and after feeding an additional non-adrenergic mechanism controlling gut blood flow was demonstrated.
Abstract: Cardiac output, ventral and dorsal aortic blood pressure, heart rate, and coeliac and mesenteric artery blood flow were recorded simultaneously in the Atlantic cod, Gadus morhua L., at rest, during exercise, during hypoxia and after feeding. In the resting unfed animals, coeliac artery blood flow was 4.1 +/- 0.8 ml min-1 kg-1 and mesenteric artery blood flow was 3.5 +/- 1.1 ml min-1 kg-1 (mean +/- S.E.M., N = 10); together, these flows represent approximately 40% of the cardiac output. Exercise or exposure to hypoxia resulted in increased visceral vascular resistance, leading to reductions in the coeliac and mesenteric artery blood flows. Coeliac and mesenteric blood flows were increased 24 h after feeding and the coeliac and systemic vascular resistances decreased in comparison with the prefeeding values. Phentolamine did not affect the gastrointestinal artery blood flow, but produced a significant decrease in the mesenteric and systemic vascular resistance. Treatment with bretylium and phentolamine revealed differences between the coeliac and the mesenteric vasculature regarding the control mechanisms during hypoxia and during exercise and feeding. During hypoxia, an adrenergic control of the gastrointestinal vasculature with both nervous and humoral components was found, whereas during exercise and after feeding an additional non-adrenergic mechanism controlling gut blood flow was demonstrated.
144 citations
TL;DR: Overall, sprint training minimizes endogenous fuel depletion during exhaustive swimming, even though swim speed (and distance) increases, and enhances the rate of metabolic recovery following the swim, suggesting increased use of exogenous glucose.
Abstract: Summary Experimental fish were sprint trained by individual chasing for 30 s on alternate days for 9 weeks. Ten trained and 10 untrained animals were rapidly freezeclamped at rest and 0,1 , 3 and 6h after a 5-min chase. Swimming speed of 10 fish in each group was measured in a 2-min chase. Phosphocreatine (PCr), creatine, adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), glycogen, glucose-1-phosphate (G-l-P), glucose-6-phosphate (G-6-P), fructose-6-phosphate (Fru-6-P), glucose, glycerol-3-phosphate (Glyc-3P), pyruvate and lactate were measured on extracts from freeze-dried white muscle. Trained fish swam 14% further in 2min, with 90% of this difference occurring between 20 and 50 s. Trained fish accumulated 32% more lactate, but showed no differences in glycogen or PCr depletion, and 22 % less ATP depletion, suggesting increased use of exogenous glucose. Glycogen repletion in early recovery, and lactate clearance between 1 and 3h after exercise, were also enhanced in trained fish. Energy stores (ATP equivalents) were higher after exercise and especially during recovery in trained fish. Overall, sprint training minimizes endogenous fuel depletion during exhaustive swimming, even though swim speed (and distance) increases, and enhances the rate of metabolic recovery following the swim.
106 citations
TL;DR: A biologically based toxicokinetic model developed to stimulate the metabolic disposition of pyrene in trout with an average body weight of 450 g and dosed with a single bolus injection of the chemical was validated by comparing the model predicted and experimental results.
61 citations
TL;DR: In this paper, a spontaneously ventilating, blood-perfused trout preparation was used to examine gas exchange across the gills, and it was concluded that trout gills are primarily perfusion limited for oxygen uptake under resting normoxic conditions, but decreases in diffusion limitations come into play under stress conditions such as environmental hypoxia or exercise.
Abstract: A spontaneously ventilating, blood-perfused trout preparation was used to examine gas exchange across the gills. The blood flow rate and input oxygen content to the branchial circulation were manipulated to assess the contributions of perfusion and diffusion limitations to oxygen transfer. Increases in the flow rate (Q), or the haematocrit (Hct) were positively correlated with increases in the oxygen uptake across the gills (M g, O g, O2 ). Manipulation of pulse pressure or frequency of the pump, with no changes to Q had no effect on M g, O g, O2 . Addition of adrenaline (1 × 10 −6 M) to the blood also did not effect M g, O g, O2 . Calculations of cardiac output from the Fick principle always yielded values which were overestimates of the actual cardiac output (Q) set by the mechanical pump. The difference between the measured oxygen uptake by the fish from the water (Vg 1, O 1, O2 ) and the amount of oxygen transferred to the blood across the gills (Vg 1, O 1, O2 ) was a reflection of gill tissue metabolism. It is concluded that trout gills, like mammalian lungs, are primarily perfusion limited for oxygen uptake under resting normoxic conditions, but decreases in diffusion limitations come into play under stress conditions, such as environmental hypoxia or exercise. Note:
52 citations