The effects of temperature on the cardio-respiratory function of the neotropical fish Piaractus mesopotamicus (original) (raw)
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Journal of Applied Ichthyology, 1998
The time-course for the thermal acclimation of aerobic metabolism was determined for juvenile and adult P. scrqfa by following the modifications in oxygen consumption ('O?). Fish previously acclimated at 15 and 25°C and transferred to water temperature 10°C and above, showed 3-4-fold increase in '02 in the first 6 h after the change in temperature, reaching a stable '02 level in 24 and 48 h (adult and juvenile fish, respectively). Fish acclimated a t 35 and 25°C and transferred to water temperature 10°C below that to which they were previously acclimated decreased the '02 in the first 6 h after the change in water temperature (3.0-fold lower, from 35 to 25°C for both fish sizes and 6.5-and 3.0-fold lower from 25 to 15°C for juvenile and adult fish, respectively), reaching a stable '0, level in 48 h (from 25 to 15°C) and 24-72h (from 35 to 25°C). Regardless of the direction of water temperature change, P. scrofa showed partial '02 compensation and short time-course for the adjustments in aerobic metabolism, reaching a stable rate at the new water temperature in 1-3 days. These results indicate an ecological advantage for this species, mainly for the adult fish, which migrate along rivers prior to reproduction and which may experience fluctuations in water temperature, including the heated effluents from electrical power stations.
Canadian Journal of Fisheries and Aquatic Sciences, 2014
In this first study examining the thermal tolerance of adult Arctic char (Salvelinus alpinus) acclimated to seawater, we measured their critical thermal maximum (CT Max ) and several cardiorespiratory parameters (oxygen consumption (MO 2 ), heart rate (f H ), stroke volume (S V ), cardiac output (Q), ventilatory frequency (V F ), opercular pressure (P O ), and ventilatory effort (V E )) when exposed to a temperature increase of 2°C·h −1 . Further, we directly compared these results with those obtained for the eurythermal Atlantic salmon (Salmo salar) under identical conditions. There was no significant difference in cardiorespiratory values between the two species at their acclimation temperature (9.5-10°C). In contrast, the slope of the MO 2 -temperature relationship was lower (by 27%) in the char as compared with that in the salmon, and the char had significantly lower values for maximum f H (by 13%), maximum MO 2 (by 35%), absolute metabolic scope (by 39%), and CT Max (approximately 23 versus 26.5°C, respectively). Although not a focus of the study, preliminary data suggest that interspecific differences in mitochondrial respiration (oxidative phosphorylation), and its temperature sensitivity, may partially explain the difference in thermal tolerance between the two species. These results provide considerable insights into why Atlantic salmon are displacing Arctic char in the current era of accelerated climate change.
Temperature Sensitivity of Cardiac Function in Pelagic Fishes
We measured the temperature sensitivity, adrenergic sensitivity, and dependence on sarcoplasmic reticulum (SR) Ca 2ϩ of ventricular muscle from pelagic fishes with different vertical mobility patterns: bigeye tuna (Thunnus obesus), yellowfin tuna (Thunnus albacares), and mahimahi (Coryphaena hippurus) and a single specimen from swordfish (Xiphias gladius). Ventricular muscle from the bigeye tuna and mahimahi exhibited a biphasic response to an acute decrease in temperature (from 26Њ to 7ЊC); twitch force and kinetic parameters initially increased and then declined. The magnitude of this response was larger in the bigeye tuna than in the mahimahi. Under steady state conditions at 26ЊC, inhibition of SR Ca 2ϩ release and reuptake with ryanodine and thapsigargin decreased twitch force and kinetic parameters, respectively, in the bigeye tuna only. However, the initial inotropy associated with decreasing temperature was abolished by SR inhibition in both the bigeye tuna and the mahimahi. Application of adrenaline completely reversed the effects of ryanodine and thapsigargin, but this effect was diminished at cold temperatures. In the yellowfin tuna, temperature and SR inhibition had minor effects on twitch force and kinetics, while adrenaline significantly increased these parameters. Limited data suggest that swordfish ventricular muscle responds to acute temperature reduction, SR inhibition, and adrenergic stimulation in a manner similar to that of bigeye tuna ventricular muscle. In aggregate, our results show that the temperature sensitivity, SR dependence, and adrenergic sensitivity of pelagic fish hearts are species specific and that these differences reflect species-specific vertical mobility patterns.
2020
The Alaska blackfish (Dallia pectoralis) remains active at cold temperatures when experiencing aquatic hypoxia without air access. To discern the cardiophysiological adjustments that permit this behaviour, we quantified the effect of acclimation from 15°C to 5°C in normoxia (15N and 5N fish), as well as chronic hypoxic submergence (6–8 weeks; ∼6.3–8.4 kPa; no air access) at 5°C (5H fish), on in vivo and spontaneous heart rate (fH), electrocardiogram, ventricular action potential (AP) shape and duration (APD), the background inward rectifier (IK1) and rapid delayed rectifier (IKr) K+ currents and ventricular gene expression of proteins involved in excitation–contraction coupling. In vivo fH was ∼50% slower in 5N than in 15N fish, but 5H fish did not display hypoxic bradycardia. Atypically, cold acclimation in normoxia did not induce shortening of APD or alter resting membrane potential. Rather, QT interval and APD were ∼2.6-fold longer in 5N than in 15N fish because outward IK1 and I...
Journal of Experimental Biology, 2008
SUMMARYThe mechanism underlying the decrease in aerobic scope in fish at warm temperatures is not fully understood and is the focus of this research. Our study examined oxygen uptake and delivery in resting, swimming and recovering sockeye salmon while water temperature was acutely increased from 15°C to 24°C in 2°C h–1 increments. Fish swam at a constant speed during the temperature change. By simultaneously measuring oxygen consumption(ṀO2), cardiac output (Q̇) and the blood oxygen status of arterial and venous blood, we were able to determine where in the oxygen cascade a limitation appeared when fish stopped sustained swimming as temperature increased. High temperature fatigue of swimming sockeye salmon was not a result of a failure of either oxygen delivery to the gills or oxygen diffusion at the gills because oxygen partial pressure(PO2) and oxygen content(CO2) in arterial blood did not decrease with increasing temperature, as would be predicted for such limitations. Instead,...
Journal of Experimental Biology, 2013
SUMMARYAn insufficient supply of oxygen under thermal stress is thought to define thermal optima and tolerance limits in teleost fish. When under thermal stress, cardiac function plays a crucial role in sustaining adequate oxygen supply for respiring tissues. Thus, adaptive phenotypic plasticity of cardiac performance may be critical for modifying thermal limits during temperature acclimation. Here we investigated effects of temperature acclimation on oxygen consumption, cardiac function and blood oxygen carrying capacity of a eurythermal goby fish, Gillichthys mirabilis, acclimated to 9, 19 and 26°C for 4 weeks. Acclimation did not alter resting metabolic rates or heart rates; no compensation of rates was observed at acclimation temperatures. However, under an acute heat ramp, warm-acclimated fish exhibited greater heat tolerance (CTmax=33.3, 37.1 and 38.9°C for 9°C-, 19°C- and 26°C-acclimated fish, respectively) and higher cardiac arrhythmia temperatures compared with 9°C-acclimat...
Journal of Experimental Biology, 2012
Numerous recent studies convincingly correlate the upper thermal tolerance limit of aquatic ectothermic animals to reduced aerobic scope, and ascribe the decline in aerobic scope to failure of the cardiovascular system at high temperatures. In the present study we investigate whether this ʻaerobic scope modelʼ applies to an air-breathing and semi-terrestrial vertebrate Rhinella marina (formerly Bufo marinus). To quantify aerobic scope, we measured resting and maximal rate of oxygen consumption at temperatures ranging from 10 to 40°C. To include potential effects of acclimation, three groups of toads were acclimated chronically at 20, 25 and 30°C, respectively. The absolute difference between resting and maximal rate of oxygen consumption increased progressively with temperature and there was no significant decrease in aerobic scope, even at temperature immediately below the lethal limit (41-42 o C). Haematological and cardiorespiratory variables were measured at rest and immediately after maximal activity at benign (30°C) and critically high (40°C) temperatures. Within this temperature interval, both resting and active heart rate increased, and there was no indication of respiratory failure, judged from high arterial oxygen saturation, P O2 and [Hb O2 ]. With the exception of elevated resting metabolic rate for cold-acclimated toads, we found few differences in the thermal responses between acclimation groups with regard to the cardiometabolic parameters. In conclusion, we found no evidence for temperature-induced cardiorespiratory failure in R. marina, indicating that maintenance of aerobic scope and oxygen transport is unrelated to the upper thermal limit of this air-breathing semi-terrestrial vertebrate.
Journal of Comparative Physiology B
At high temperatures, ventricular beating rate collapses and depresses cardiac output in fish. The role of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) in thermal tolerance of ventricular function was examined in brown trout (Salmo trutta) by measuring heart SERCA and comparing it to that of the dorsolateral myotomal muscle. Activity of SERCA was measured from crude homogenates of cold-acclimated (+ 3 °C, c.a.) and warm-acclimated (+ 13 °C, w.a.) brown trout as cyclopiazonic acid (20 µM) sensitive Ca2+-ATPase between + 3 and + 33 °C. Activity of the heart SERCA was significantly higher in c.a. than w.a. trout and increased strongly between + 3 and + 23 °C with linear Arrhenius plots but started to plateau between + 23 and + 33 °C in both acclimation groups. The rate of thermal inactivation of the heart SERCA at + 35 °C was similar in c.a. and w.a. fish. Activity of the muscle SERCA was less temperature dependent and more heat resistant than that of the heart SERCA and showed lin...
Cardiac tissue function of the teleost fish Oreochromis niloticus under different thermal conditions
Journal of Thermal Biology, 2000
The cardiac responses of Oreochromis niloticus acclimated to 258C were assessed using ventricle strips mounted for isometric force recording (Fc) and in vivo heart rate ( f H ). f H increased progressively from 25 to 408C. At extracellular Ca 2+ concentrations of 1.25 and 9.25 mM, a transition from 25 to 408C resulted in a decreased Fc. At both 25 and 408C, Fc rose when [Ca 2+ ] was increased from 1.25 to 9.25 mM. Fc remained constant at 72 and 120 contractionsÁmin À1 at 25 and 408C, respectively, and declined thereafter. The post-rest potentiation was not in¯uenced by ryanodine, indicating that the sarcoplasmic reticulum is not important to the excitation±contraction coupling. 7
Physiological and Biochemical Zoology, 2009
We measured the temperature sensitivity, adrenergic sensitivity, and dependence on sarcoplasmic reticulum (SR) Ca 2ϩ of ventricular muscle from pelagic fishes with different vertical mobility patterns: bigeye tuna (Thunnus obesus), yellowfin tuna (Thunnus albacares), and mahimahi (Coryphaena hippurus) and a single specimen from swordfish (Xiphias gladius). Ventricular muscle from the bigeye tuna and mahimahi exhibited a biphasic response to an acute decrease in temperature (from 26Њ to 7ЊC); twitch force and kinetic parameters initially increased and then declined. The magnitude of this response was larger in the bigeye tuna than in the mahimahi. Under steady state conditions at 26ЊC, inhibition of SR Ca 2ϩ release and reuptake with ryanodine and thapsigargin decreased twitch force and kinetic parameters, respectively, in the bigeye tuna only. However, the initial inotropy associated with decreasing temperature was abolished by SR inhibition in both the bigeye tuna and the mahimahi. Application of adrenaline completely reversed the effects of ryanodine and thapsigargin, but this effect was diminished at cold temperatures. In the yellowfin tuna, temperature and SR inhibition had minor effects on twitch force and kinetics, while adrenaline significantly increased these parameters. Limited data suggest that swordfish ventricular muscle responds to acute temperature reduction, SR inhibition, and adrenergic stimulation in a manner similar to that of bigeye tuna ventricular muscle. In aggregate, our results show that the temperature sensitivity, SR dependence, and adrenergic sensitivity of pelagic fish hearts are species specific and that these differences reflect species-specific vertical mobility patterns.