Cardiovascular changes associated with thermal polypnea in the chicken

Whittow, G. C.; Sturkie, Paul D.; Stein, Gerald H.

doi:10.1152/ajplegacy.1964.207.6.1349

Cited by 76 publications

(27 citation statements)

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“…However, similar increases in central blood volume during hyperthermia were observed in those experiments in which the tip of the arterial catheter lay in the aorta close to the heart. An increase in the central blood volume during hyperthermia has been observed in another pantin'g animal, the chicken [Whittow et al, 1964]. It would appear, therefore, that the increased respiratory movements which occur when an animal is panting are associated with an influx of blood into the thorax.…”

Section: Discussionmentioning

confidence: 96%

“…The lower respiratory rate at a rectal temperature of 41.50 C. compared with that at 40.50 C. indicates a change in the pattern of breathing which represents the failure of thermal polypncea as a physiological mechanism permitting maximal respiratory evaporative cooling with minimal disturbance of the blood gases [Whittow, 1965;Whittow et al, 1964]. It is of direct interest to consider whether there was any evidence of circulatory failure in severe heat-stress.…”

Section: Discussionmentioning

confidence: 99%

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THE EFFECT OF HYPERTHERMIA ON THE SYSTEMIC AND PULMONARY CIRCULATION OF THE OX (Bos taurus)

Whittow

1965

Exp Physiol

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The cardiac output, arterial blood pressure, pulmonary arterial pressure, heart rate, blood volume, respiratory rate and rectal temperature of the unanaesthetized ox have been measured at environmental temperatures of 150 C. and 400 C. (low humidity) and also during hyperthermia induced by increasing the humidity of the hot environment (400 C.). Derived values for total peripheral resistance, central blood volume and cardiac work were obtained from the measured data.The cardiac output, central blood volume and respiratory rate were significantly higher, while the mean blood pressure and calculated total peripheral resistance were significantly lower, in the hot dry environment than they were at 15°C. These results seemed to be consistent with the hypothesis that a peripheral vasodilatation and an increased venous return occurred in the hot dry environment.The increase in systemic arterial blood pressure during hyperthermia was attributed to the concomitant increase in cardiac output because the total peripheral resistance diminished. The increase in the cardiac output was the result of an increased heart rate. At a rectal temperature of 41.50 C. the stroke volume of the heart was considerably lower than its control value at an environmental temperature of 15°C. The work of the heart was increased during hyperthermia.The increased respiratory activity in hyperthermic animals was associated with a diminution of the mean pulmonary arterial pressure and an increase in the central blood volume.No statistically significant differences in plasma or blood volumes of the animals were recorded between environments of 150 C. and 400 C. (low humidity) and 400 C.(high humidity). The plasma volume tended to diminish during hyperthermia while the blood volume tended to be maintained close to its control value as a result of an increase in the proportion of red cells in the blood.At a rectal temperature of 41.50 C. none of the animals was in a state of circulatory failure, but there was evidence that their cardiovascular systems were severely stressed at this temperature.IN a previous paper [Ingram and Whittow, 1963] it was reported that the arterial blood pressure of the unan2esthetized ox increases during hyperthermia. The cause of the increase in blood pressure was not established. One of the purposes of the experiments described in the present report was therefore to examine the relative contribution of an increase in cardiac output, blood volume and total peripheral resistance to the pressor response to hyperthermia. An additional object of the present investigation was to determine if the increase in systemic arterial blood pressure during hyperthermia was associated with a change in pulmonary arterial pressure and in the volume of blood in the lungs. The ox is a panting animal; a considerable increase in both respiratory rate and minute volume occur during hyperthermia [Findlay, 1957; Whittow, 1962, 1963]. Little is known about the effects of thermal polypncea and of the slower deeper type of

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

THE EFFECT OF HYPERTHERMIA ON THE SYSTEMIC AND PULMONARY CIRCULATION OF THE OX (Bos taurus)

Whittow

1965

Exp Physiol

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“…Proteosynthesis and proteolysis signaling pathways in the muscle were also reported to be affected by 2 weeks of heat exposure (Boussaid-Om Ezzine et al, 2010). In the long term, chronic heat exposure has been described as increasing plasma volume expansion (Whittow et al, 1964;Yahav et al, 1997) and inducing a redistribution of blood flow, especially toward peripheral tissues (Wolfenson, 1986;Giloh et al, 2012). Such physiological responses probably enhance sensible heat loss.…”

Section: Effects Of Heat Exposure On Avian Physiologymentioning

confidence: 99%

Cyclic variations in incubation conditions induce adaptive responses to later heat exposure in chickens: a review

Lavstsen

Bedrani

Berri

et al. 2015

Animal

102

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Selection programs have enabled broiler chickens to gain muscle mass without similar enlargement of the cardiovascular and respiratory systems that are essential for thermoregulatory efficiency. Meat-type chickens cope with high ambient temperature by reducing feed intake and growth during chronic and moderate heat exposure. In case of acute heat exposure, a dramatic increase in morbidity and mortality can occur. In order to alleviate heat stress in the long term, research has recently focused on early thermal manipulation. Aimed at stimulation of long-term thermotolerance, the thermal manipulation of embryos is a method based on fine tuning of incubation conditions, taking into account the level and duration of increases in temperature and relative humidity during a critical period of embryogenesis. The consequences of thermal manipulation on the performance and meat quality of broiler chickens have been explored to ensure the potential application of this strategy. The physiological basis of the method is the induction of epigenetic and metabolic mechanisms that control body temperature in the long term. Early thermal manipulation can enhance poultry resistance to environmental changes without much effect on growth performance. This review presents the main strategies of early heat exposure and the physiological concepts on which these methods were based. The cellular mechanisms potentially underlying the adaptive response are discussed as well as the potential interest of thermal manipulation of embryos for poultry production.

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“…Stroke volume was calculated from cardiac output and heart rate. Total peripheral resistance to blood flow was calculated as described by Whittow, Sturkie and Stein [1964].…”

Section: Measurementsmentioning

confidence: 99%

The Oxygen Consumption, Fatty Acid and Glycerol Uptake of the Liver in Fed and Fasted Sheep During Cold Exposure

1975

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The effect of a short period (3-4 hr) of exposure to cold on the liver's circulation and metabolism has been studied in sheep fed 6 hr or 21 hr before experiment.In the cold the animals had a significantly increased heart rate, cardiac output, hepatic portal blood flow, mean arterial blood pressure and pulse pressure. Total peripheral resistance fell in the fasted animals when they were exposed to cold, but not the more recently fed animals. Exposure to cold significantly increased the total body oxygen consumption and oxygen consumption of the liver, but not that of the portal-drained viscera (gut, spleen, pancreas, omental adipose tissue). Recent feeding significantly increased the net rate of release of volatile fatty acids from the portal-drained viscera, and significantly increased their net rate of uptake by the liver. In the recently fed animals, exposure to cold further increased the visceral release, portal plasma concentration, and hepatic uptake of volatile fatty acids. Exposure to cold, and fasting, both significantly increased the circulating (arterial) plasma level of free fatty acids and glycerol, and increased their net rate of uptake by the liver, significantly in cold exposure but not in fasting.The results show that the liver makes a small contribution to the total increase in oxygen consumption in the cold. The liver also has an increased uptake of fatty acids and glycerol during cold exposure.Mammals increase their total body oxygen consumption (V02), and therefore heat production, when they are exposed to cold. It is not known precisely which tissues are responsible for this increase. In particular it is not known to what extent the liver is one of the organs in the body that has an increased heat production during cold exposure. Functional evisceration of anaesthetized cold-acclimated rats, which includes ligation of the portal vein, does not prevent them from increasing their total body VO2 in the cold, by the same amount as control animals. However, this technique does not eliminate the possibility that other tissues may compensate for any loss of liver heat production [Depocas, 1958]. Measurements of the temperature difference between the hepatic vein and the hepatic portal vein in unanaesthetized dogs show an increase in the temperature difference when ice is applied to the skin of the animal [Fedorov and Shur, 1942] suggesting an increase in liver heat production in response to a cold stimulus. Similar measurements of liver temperature, corrected for liver blood flow (Q), show a fall in liver heat production when unanaesthetized rats, acclimated to 20°C, are put into a warmer environment [Stoner, 1973].The present experiments were designed to measure the V02 of the liver and relate this to total body V02 during acute cold exposure of unanaesthetized sheep. In view of the reported changes in lipid oxidation in sheep during cold exposure [Graham, Wainman, Blaxter and Armstrong, 1959] and the increase in circulating free fatty acids (FFA) [Bost and Dorleac, 1965] and glycerol 107

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Cardiovascular changes associated with thermal polypnea in the chicken

Cited by 76 publications

References 0 publications

THE EFFECT OF HYPERTHERMIA ON THE SYSTEMIC AND PULMONARY CIRCULATION OF THE OX (Bos taurus)

THE EFFECT OF HYPERTHERMIA ON THE SYSTEMIC AND PULMONARY CIRCULATION OF THE OX (Bos taurus)

Cyclic variations in incubation conditions induce adaptive responses to later heat exposure in chickens: a review

The Oxygen Consumption, Fatty Acid and Glycerol Uptake of the Liver in Fed and Fasted Sheep During Cold Exposure

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