Influence of sudden temperature changes on oxygen consumption and heart rate in chickens in light and dark environments

1978 ◽  
Vol 90 (3) ◽  
pp. 605-609 ◽  
Author(s):  
M. Van Kampen ◽  
B. W. Mitchell ◽  
H. S. Siegel

SummarySeven-week-old White Rock males were exposed to step-wise increases in ambient temperatures from 7·7 to 37·7 °C in light and dark environments. Heart rate decreased with increasing ambient temperature with a quadratic slope (P ≤ 0·0001). Heart rate was lower during the dark period than during the light period (P ≤ 0·06). There was a positive linear correlation between heart rate and oxygen consumption (γ = 0·997) for ambient temperatures from 7·7 to 37·7 °C.Body temperatures began to increase significantly when ambient temperature reached beyond 27·5 °C. The increases followed a quadratic slope (P ≤ 0·0001). Body temperatures during the light period were significantly higher than during the dark period (P ≤ 0·05).

1975 ◽  
Vol 53 (6) ◽  
pp. 679-685 ◽  
Author(s):  
J. B. Holter ◽  
W. E. Urban Jr. ◽  
H. H. Hayes ◽  
H. Silver ◽  
H. R. Skutt

Six adult white-tailed deer (Odocoileus virginianus borealis) were exposed to 165 periods of 12 consecutive hours of controlled constant ambient temperature in an indirect respiration calorimeter. Temperatures among periods varied from 38 to 0 (summer) or to −20C (fall, winter, spring). Traits measured were energy expenditure (metabolic rate), proportion of time spent standing, heart rate, and body temperature, the latter two using telemetry. The deer used body posture extensively as a means of maintaining body energy equilibrium. Energy expenditure was increased at low ambient temperature to combat cold and to maintain relatively constant body temperature. Changes in heart rate paralleled changes in energy expenditure. In a limited number of comparisons, slight wind chill was combatted through behavioral means with no effect on energy expenditure. The reaction of deer to varying ambient temperatures was not the same in all seasons of the year.


1995 ◽  
Vol 198 (4) ◽  
pp. 931-937 ◽  
Author(s):  
M B Harris ◽  
W K Milsom

The relative role of the parasympathetic nervous system during deep hibernation is enigmatic. Conflicting hypotheses exist, and both sides draw support from investigations of vagal influence on the heart. Recent studies have shown cardiac chronotropic and inotropic effects of parasympathetic stimulation and inhibition in isolated hearts and anesthetized animals at hibernating body temperatures. No studies, however, have demonstrated such occurrences in undisturbed deeply hibernating animals. The present study documents respiratory-related alterations in heart rate during euthermia and hibernation at ambient temperatures of 15, 10 and 5 degrees C mediated by parasympathetic influence. During quiet wakefulness, euthermic squirrels breathed continuously and exhibited a 29% acceleration in heart rate during inspiration. During deep undisturbed hibernation, at 15, 10 and 5 degrees C ambient temperature, animals exhibited an episodic breathing pattern and body temperatures were slightly above ambient temperature. At each temperature, heart rate during the respiratory episode was greater than that during the apnea. The magnitude of this ventilatory tachycardia decreased with ambient temperature, being 108% at 15 degrees C, 32% at 10 degrees C and 11.5% at 5 degrees C. Animals exposed to 3% CO2 at 5 degrees C, which significantly increased ventilation, still exhibited an 11.7% increase in heart rate during breathing. Thus, the magnitude of the ventilation tachycardia was independent of the level of ventilation, at least over the range studied. Inhibition of vagus nerve conduction at 5 degrees C was achieved using localized nerve block. This led to an increase in apneic heart rate and abolished the ventilatory tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)


1996 ◽  
Vol 30 (1) ◽  
pp. 7-12 ◽  
Author(s):  
K. Ishii ◽  
M. Kuwahara ◽  
H. Tsubone ◽  
S. Sugano

We have studied the physiological and behavioural responses in small rodents to ambient alterations. For this purpose, voles and mice were exposed to relatively low (12°C) and high (35°C) ambient temperatures, and heart rate (HR), locomotor activity (LA) and body temperature (BT) were recorded using telemetry system. The control HR (at 24°C) of voles was lower than that of mice. The 'heat exposure' decreased HR to 85.0±3.3% in voles, and to 78.0±3.2% in mice compared with the mean HR of the same time in the control day. The 'cold exposure' increased the HR to 131.9±8.8% in voles, and 119±10.9% in mice. The decreasing rate of HR in heat exposure was smaller in voles than mice, and in cold exposure the increased rate was larger in voles than mice. Cold exposure decreased BT in both species; 96.1±0.5% in voles and 93.7±1.0% in mice. The LA was not changed significantly by heat exposure in either species, but was partially increased by cold exposure. These results demonstrate that telemetry was helpful for qualitative and quantitative behavioural studies in small rodents, and confirmed that the physiological and behavioural responses to ambient temperature changes differed between these animals.


1991 ◽  
Vol 69 (7) ◽  
pp. 1842-1847 ◽  
Author(s):  
Gregory K. Snyder ◽  
Joseph R. Coelho ◽  
Dalan R. Jensen

In chicks the ability to regulate body temperature to adult levels develops during the first 2 weeks of life. We examined whether the ability of young chicks to regulate body temperature is increased by elevated levels of the thyroid hormone 3,3′5-triiodothyronine. By 13 days following hatch, body temperatures of chicks were not significantly different from those expected for adult birds. Furthermore, at an ambient temperature of 10 °C, 13-day-old control chicks were able to maintain body temperature, and elevated serum thyroid hormone levels did not increase rates of oxygen consumption or body temperature above control values. Six-day-old chicks had body temperatures that were significantly lower than those of the 13-day-old chicks and were not able to regulate body temperature when exposed to an ambient temperature of 10 °C. On the other hand, 6-day-old chicks with elevated serum thyroid hormone had significantly higher rates of oxygen consumption than 6-day-old control chicks, and were able to maintain constant body temperatures during cold exposure. The increased oxygen consumption rates and improved ability to regulate body temperature during cold exposure were correlated with increased citrate synthase activity in skeletal muscle. Our results support the argument that thyroid hormones play an important role in the development of thermoregulatory ability in neonate birds by stimulating enzyme activities associated with aerobic metabolism.


1962 ◽  
Vol 15 (2) ◽  
pp. 386 ◽  
Author(s):  
PR Morrison

Body temperature measurements on the short-nosed bandicoot (Thylacis obeaulus) have shown a nocturnal cycle with a range of 1� 2�C and a short active phase at 2200-0400 hr. The bilby or rabbit bandicoot (Macrotis lagoti8) had a sharply defined temperature cycle, with a range of almost 3�C after several months of captivity, during which the day-time resting temperature was progressively lowered from 36� 4 to 34� 2�C. Forced activity raised the diurnal temperature substantially but not to the nocturnal level. Forced activity did not raise the nocturnal level which was similar in the two species (37' O�C). Both species could regulate effectively at an ambient temperature of 5�C, but only Thylaci8 showed regulation at ambient temperatures of between 30 and 40�C.


1971 ◽  
Vol 13 (2) ◽  
pp. 303-313 ◽  
Author(s):  
D. B. Stephens

SUMMARY1. The metabolic rates of 58 individual piglets kept either on a straw or on a concrete floor at ambient temperatures near to 10°, 20° or 30°C have been measured with ages ranging from newborn to 9 days, and body weight from 1·0 to 3·2 kg. The oxygen consumption was measured on each floor material at the chosen ambient temperature thus allowing paired comparisons for each animal.2. In comparison with the concrete floor, oxygen consumption on straw was reduced by 18% at 10°C, 27% at 20°C and by 12% at 30°C for pigs 2 to 9 days old. The regression coefficients of mean log (oxygen consumption) on log (body weight) were around 0·66 at 10° and 20°C. At 30°C the value was 0·99 ± 0·14. The regression coefficients were not significantly affected by the presence of a straw floor showing that its effect did not vary with body weight. Corresponding values foi piglets below 24 hours of age were 17% at 10°C, 27% at 20°C and 22% at 30°C ambient temperature.3. Moving a piglet on to a straw floor at 10°C had the same thermal effect as raising the ambient temperature to 18°C. Similar treatment at 30°C was equivalent to raising the ambient temperature to 32°C.4. Lowering ambient temperature to increase the temperature gradient between the homeothermic body of the piglet and the environment progressively increased heat loss in all cases. There was a concomitant decrease in the calculated conductance between core and environment which was more pronounced for the piglets lying on the concrete floor.


2017 ◽  
Vol 4 (12) ◽  
pp. 171359 ◽  
Author(s):  
M. Teague O'Mara ◽  
Sebastian Rikker ◽  
Martin Wikelski ◽  
Andries Ter Maat ◽  
Henry S. Pollock ◽  
...  

Reduction in metabolic rate and body temperature is a common strategy for small endotherms to save energy. The daily reduction in metabolic rate and heterothermy, or torpor, is particularly pronounced in regions with a large variation in daily ambient temperature. This applies most strongly in temperate bat species (order Chiroptera), but it is less clear how tropical bats save energy if ambient temperatures remain high. However, many subtropical and tropical species use some daily heterothermy on cool days. We recorded the heart rate and the body temperature of free-ranging Pallas' mastiff bats ( Molossus molossus ) in Gamboa, Panamá, and showed that these individuals have low field metabolic rates across a wide range of body temperatures that conform to high ambient temperature. Importantly, low metabolic rates in controlled respirometry trials were best predicted by heart rate, and not body temperature . Molossus molossus enter torpor-like states characterized by low metabolic rate and heart rates at body temperatures of 32°C, and thermoconform across a range of temperatures. Flexible metabolic strategies may be far more common in tropical endotherms than currently known.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Ulrich Lutz ◽  
Thomas Nussbaumer ◽  
Manuel Spannagl ◽  
Julia Diener ◽  
Klaus FX Mayer ◽  
...  

Cool ambient temperatures are major cues determining flowering time in spring. The mechanisms promoting or delaying flowering in response to ambient temperature changes are only beginning to be understood. In Arabidopsis thaliana, FLOWERING LOCUS M (FLM) regulates flowering in the ambient temperature range and FLM is transcribed and alternatively spliced in a temperature-dependent manner. We identify polymorphic promoter and intronic sequences required for FLM expression and splicing. In transgenic experiments covering 69% of the available sequence variation in two distinct sites, we show that variation in the abundance of the FLM-ß splice form strictly correlate (R2 = 0.94) with flowering time over an extended vegetative period. The FLM polymorphisms lead to changes in FLM expression (PRO2+) but may also affect FLM intron 1 splicing (INT6+). This information could serve to buffer the anticipated negative effects on agricultural systems and flowering that may occur during climate change.


1960 ◽  
Vol 199 (2) ◽  
pp. 243-245 ◽  
Author(s):  
H. A. Leon ◽  
S. F. Cook

The oxygen consumption of male Long-Evans rats was determined at three different ambient temperatures in air and in an equivalent helium-oxygen mixture. It was found that when the ambient temperature is near the skin temperature of the rat, the effect of helium is insignificant. If the ambient temperature is lowered, helium induces an increased metabolism over air at the same temperature. Since helium has a thermal conductivity about six times greater than nitrogen, it is concluded that the accelerated metabolism is in response to the greater heat loss in the presence of helium and the magnitude of this response is proportional to the thermal gradient between the animal and the environment.


1965 ◽  
Vol 20 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Hermann Pohl

Characteristics of cold acclimation in the golden hamster, Mesocricetus auratus, were 1) higher metabolic rate at -30 C, 2) less shivering when related to ambient temperature or oxygen consumption, and 3) higher differences in body temperature between cardiac area and thoracic subcutaneous tissues at all ambient temperatures tested, indicating changes in tissue insulation. Cold-acclimated hamsters also showed a rise in temperature of the cardiac area when ambient temperature was below 15 C. Changes in heat distribution in cold-acclimated hamsters suggest higher blood flow and heat production in the thoracic part of the body in the cold. The thermal conductance through the thoracic and lumbar muscle areas, however, did not change notably with lowering ambient temperature. Marked differences in thermoregulatory response to cold after cold acclimation were found between two species, the golden hamster and the thirteen-lined ground squirrel, showing greater ability to regulate body temperature in the cold in hamsters. hibernator; oxygen consumption— heat production; body temperature — heat conductance; muscular activity — shivering; thermoregulation Submitted on July 6, 1964


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