Thermoregulatory heat production in cold-reared and warm-reared pigs

1983 ◽  
Vol 244 (2) ◽  
pp. R273-R278 ◽  
Author(s):  
M. Heath ◽  
D. L. Ingram
Keyword(s):  
Heat Flow ◽  
Skin Temperature ◽  
Heat Production ◽  
O2 Consumption ◽  
Nonshivering Thermogenesis ◽  
Ambient Temperatures ◽  
Ad Libitum

Pigs were reared from 2 wk of age in either 10 or 35 degrees C and fed ad libitum. At 8 wk of age they were tested for the presence of regulatory nonshivering thermogenesis by administration of norepinephrine (NE) and propranolol. In addition, an electromyogram and carotid temperature, as well as a heat flow and skin temperature from one site, were monitored while the pigs were at ambient temperatures of 10, 15, 20, 25, and 30 degrees C. Cold-reared pigs showed a heightened response to NE in cold compared to thermally neutral environments. This was not observed in warm-reared pigs. Propranolol depressed O2 consumption more in cold-reared than in warm-reared pigs. Pigs reared in the cold also showed a higher intensity of shivering, tissue conductance, and skin temperature than warm-reared littermates. The shivering response of cold-reared pigs was more sensitive to changes in skin temperature than in warm-reared pigs.

Effects of altered ambient temperature on metabolic rate during CO2 inhalation

1985 ◽  
Vol 58 (5) ◽  
pp. 1592-1596 ◽  
Author(s):  
R. P. Kaminski ◽  
H. V. Forster ◽  
G. E. Bisgard ◽  
L. G. Pan ◽  
S. M. Dorsey ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Heat Production ◽  
Pulmonary Ventilation ◽  
O2 Consumption ◽  
Breathing Frequency ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Respiratory Heat Loss ◽  
Unit Increase ◽  
Stimulation Of

The purpose of this study was to determine if the changes in O2 consumption (VO2) during CO2 inhalation could in part be due to stimulation of thermogenesis for homeothermy. Twelve ponies were exposed for 30-min periods to inspired CO2 (PIco2) levels of less than 0.7, 14, 28, and 42 Torr during the winter at 5 (neutral) and 23 degrees C ambient temperatures (TA) and during the summer at 21 (neutral TA), 30, and 12 degrees C. Elevating TA in both seasons resulted in an increased pulmonary ventilation (VE) and breathing frequency (f) (P less than 0.01) but no significant increase in VO2 (P greater than 0.05). Decreasing TA in the summer resulted in a decrease in VE and f (P less than 0.01) but no significant change in VO2 (P greater than 0.05). At neutral TA in both seasons, VO2 increased progressively (P less than 0.05) as PIco2 was increased from 14 to 28 and 42 Torr. The increases in VO2 during CO2 inhalation were attenuated (P less than 0.05) at elevated TA and accentuated at the relatively cold TA in the summer (P less than 0.05). Respiratory heat loss (RHL) during CO2 inhalation was inversely related to TA. Above a threshold RHL of 2 cal X min-1 X m-2, metabolic heat production (MHP) increased 0.3 cal X min-1 X m-2 for each unit increase in RHL during CO2 inhalation at the neutral and elevated TA. However, during cold stress in the summer, the slope of the MHP-RHL relationship was 1.6, indicating an increased MHP response to RHL.

scholarly journals Modelling heat production and energy balance in group-housed growing pigs exposed to low or high ambient temperatures

2001 ◽  
Vol 85 (1) ◽  
pp. 97-106 ◽  
Author(s):  
N. Quiniou ◽  
J. Noblet ◽  
J. van Milgen ◽  
S. Dubois
Keyword(s):  
Physical Activity ◽  
Energy Balance ◽  
Heat Production ◽  
Growing Pigs ◽  
Large White ◽  
Ambient Temperatures ◽  
Feed Cost ◽  
Metabolisable Energy ◽  
Ad Libitum ◽  
Thermic Effect

The effects of ambient temperature (T; 12–29°C), body weight (BW; 30–90 kg) and metabolisable energy intake (ME) on components of energy balance were studied in seven groups of Piétrain × Large White barrows kept in a respiratory chamber. In Expt 1 (groups 1, 2 and 3), T varied in a cyclic way from 22°C to 12°C and then from 12°C to 22°C with three or four consecutive days at each of 22, 19, 16, 14 and 12°C. Similarly, in Expt 2 (groups 4, 5 and 6), T varied from 19 to 29°C and then from 29 to 19°C with three or four consecutive days at each of 19, 22, 25, 27 and 29°C. In both experiments, pigs were offered feedad libitum. In Expt 3, pigs (group 7) were exposed to the thermic conditions of Expt 1 but their feed allowance was adjusted on a BW basis to thead libitumintake recorded at 19 and 22°C in Expt 1. Groups 1, 2, 4, 5 and 7 were used over two successive cycles with initial average BW of 37 kg at cycle 1 (four pigs per group) and 63 kg at cycle 2 (three pigs per group). Groups 3 and 6 were studied at an intermediary stage of growth; their initial BW was 45 kg. The O2and CO2concentrations, physical activity and feed intake were continuously and simultaneously measured and used to calculate total heat production (HP; HPtot), HP due to physical activity (HPact), activity-free HP (HP0), and thermic effect of feed. HP was modelled as a non-linear function with T, BW and ME as predictors. Results indicate that all components of HP were proportional to BW0·60. Physical activity was minimal between 19 and 27°C (8 % ME). The estimated lower critical temperature was 24°C. Between 24 and 12°C, total thermic effect of feed decreased from 31 to 16 % ME, but the short-term thermic effect of feed (5·1 % ME) remained constant. Equations for prediction of HPtot, HPactand HP0according to BW, T and ME are proposed and evaluated according to literature values; values for the feed cost of thermoregulation in pigs are proposed.

scholarly journals Quantification of the Capacity for Cold-Induced Thermogenesis in Young Men With and Without Obesity

2019 ◽  
Vol 104 (10) ◽  
pp. 4865-4878 ◽  
Author(s):  
Robert J Brychta ◽  
Shan Huang ◽  
Juan Wang ◽  
Brooks P Leitner ◽  
Jacob D Hattenbach ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Critical Temperature ◽  
Energy Expenditure ◽  
Heat Production ◽  
Basal Metabolic Rate ◽  
Muscle Activity ◽  
Brown Fat ◽  
Nonshivering Thermogenesis ◽  
Ambient Temperatures ◽  
Lower Critical Temperature

AbstractObjectiveCold exposure increases energy expenditure (EE) and could have a role in combating obesity. To understand this potential, we determined the capacity for cold-induced thermogenesis (CIT), the EE increase above the basal metabolic rate at the individualized coldest tolerable temperature before overt shivering.DesignDuring a 13-day inpatient protocol, we quantitated the EE of 12 lean men and 9 men with obesity at various randomly ordered ambient temperatures in a room calorimeter. Subjects underwent brown fat imaging after exposure to their coldest tolerable temperature.ResultsCIT capacity was 300 ± 218 kcal/d (mean ± SD) or 17 ± 11% in lean men and 125 ± 146 kcal/d or 6 ± 7% in men with obesity (P = 0.01). The temperature below which EE increased, lower critical temperature (Tlc), was warmer in lean men than men with obesity (22.9 ± 1.2 vs 21.1 ± 1.7°C, P = 0.03), but both had similar skin temperature (Tskin) changes and coldest tolerable temperatures. Whereas lean subjects had higher brown fat activity, skeletal muscle activity increased synchronously with CIT beginning at the Tlc in both groups, indicating that muscle is recruited for CIT in parallel with brown fat, not sequentially after nonshivering thermogenesis is maximal.ConclusionsDespite greater insulation from fat, men with obesity had a narrower range of tolerable cool temperatures available for increasing EE and less capacity for CIT than lean men, likely as a result of greater basal heat production and similar perception to Tskin cooling. Further study of the reduced CIT capacity in men with obesity may inform treatment opportunities for obesity.

Effect of ketamine on thermoregulation in rats

1978 ◽  
Vol 56 (6) ◽  
pp. 963-967 ◽  
Author(s):  
M. T. Lin ◽  
C. F. Chen ◽  
I. H. Pang
Keyword(s):  
Drug Treatment ◽  
Skin Temperature ◽  
Rectal Temperature ◽  
Heat Production ◽  
Intraperitoneal Administration ◽  
Metabolic Heat Production ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Dose Dependent ◽  
Skin Temperatures

Intraperitoneal administration of ketamine produced dose-dependent hypothermia at the ambient temperatures (Ta) of both 8 and 23 °C in unanesthetized rats. At a Ta of 8 °C, the hypothermia was brought about solely by a decrease in metabolic heat production. There were no changes in either the tail skin temperature (Ttail) or the sole skin temperature (Tsole). At a Ta of 23 °C, the hypothermia was due to an increase in Ttail, an increase in Tsole, and a decrease in metabolic heat production. However, at a Ta of 31 °C, there were no changes in rectal temperature in response to ketamine application, since neither heat production nor skin temperatures (e.g., Ttail and Tsole) was affected by ketamine at this Ta. The data indicate that the effect of the drug treatment may be to decrease heat production and (or) increase heat loss.

Temperature regulation and heat dissipation during flight in birds

1976 ◽  
Vol 65 (2) ◽  
pp. 471-482 ◽  
Author(s):  
J. R. Torre-Bueno
Keyword(s):  
Steady State ◽  
Heat Flow ◽  
Skin Temperature ◽  
Core Temperature ◽  
Heat Dissipation ◽  
Sturnus Vulgaris ◽  
The Body ◽  
Ambient Temperatures ◽  
Flow Through ◽  
Animal Skin

Core and skin temperature were measured by radiotelemetry in starlings (Sturnus vulgaris) during 30 min flights in a wind tunnel. Core temperature was independent of ambient temperature from 0 to 28 degrees C. The temporal mean of the monitored core temperature during flight was 42-7 degrees C in one bird and 44-0 degrees C in another. These temperatures are 2-4 degrees C higher than the resting temperature in starlings, and are among the highest steady-state temperatures observed in any animal. Skin temperature on the breast was within a few degrees of core temperature. In some locations skin temperature was higher at low ambient temperatures than at intermediate ambient temperatures. An analysis of the data shows that a high core temperature does not function as an aid to head dissipation. On the contrary, insulation is adjusted to maintain a high temperature, presumably because it is necessary for flight. The increase in skin temperature at low ambient temperatures is believed to be a result of a decrease in heat flow through the breast feathers brought about by feather adjustments, to compensate for an unavoidable increase in heat flow in unfeathered or poorly feathered parts of the body.

scholarly journals A calorimetry system for metabolism trials

2007 ◽  
Vol 59 (2) ◽  
pp. 495-500 ◽  
Author(s):  
N.M. Rodríguez ◽  
W.E. Campos ◽  
M.L. Lachica ◽  
I. Borges ◽  
L.C. Gonçalves ◽  
...  
Keyword(s):  
Heat Production ◽  
Indirect Calorimetry ◽  
Rapid Determination ◽  
Minas Gerais ◽  
Standard Test ◽  
Medium Size ◽  
O2 Consumption ◽  
Ch4 Production ◽  
Ad Libitum

An indirect calorimetry system for rapid determination of CO2 and CH4 production and O2 consumption to estimate heat production of animals was built at Escola de Veterinária da Universidade Federal de Minas Gerais, Brazil. Procedures for determination of correction and calibration factors for gas analyzers and the whole system, using standard test gases were described. In addition, a metabolic trial was performed to evaluate heat production of lambs fed ad libitum. It is concluded that the system is suitable for heat production determinations in small and medium size animals.

Ontogeny of homeothermy in the immature rat: metabolic and thermal responses

1986 ◽  
Vol 60 (4) ◽  
pp. 1190-1197 ◽  
Author(s):  
D. E. Spiers ◽  
E. R. Adair
Keyword(s):  
Steady State ◽  
Metabolic Rate ◽  
Skin Temperature ◽  
Thermal Insulation ◽  
Primary Factor ◽  
O2 Consumption ◽  
Immature Rat ◽  
Ambient Temperatures ◽  
Thermoregulatory Responses ◽  
Age Dependent

Steady-state thermoregulatory responses were measured in the immature rat at 5, 7, 9, 11, 13, 15, 17, and 19 days of age. Tests were conducted at controlled ambient temperatures (Ta) ranging from 22.5 to 37.0 degrees C. Colonic (Tco) and skin (tail, interscapular, abdominal) temperatures were measured, as was O2 consumption from which metabolic rate (M) was calculated. Significant improvements in homeothermic ability occurred from 5 to 19 days of age. Although the resting level of M (RMR) increased by 6.9 W/m2 and the lower Ta limit for RMR (LCT) decreased by 2.5 degrees C as age advanced from 5 to 19 days, Tco at LCT was 36.8–37.1 degrees C at all ages studied. Below LCT the elevation of M to a given decrease in Tco was greater the older the animal. A comparable response to a change in skin temperature was not age dependent. Improvement in thermal insulation was the primary factor responsible for increases in homeothermic ability between 5 and 19 days of age.

Stimulation of ventromedial hypothalamus induces cold defense responses in conscious rabbits

1986 ◽  
Vol 250 (4) ◽  
pp. R560-R566 ◽  
Author(s):  
A. Morimoto ◽  
N. Murakami ◽  
T. Ono ◽  
T. Watanabe ◽  
Y. Sakata
Keyword(s):  
Electrical Stimulation ◽  
Heat Loss ◽  
Heat Production ◽  
Defense Responses ◽  
Ventromedial Hypothalamus ◽  
O2 Consumption ◽  
Nonshivering Thermogenesis ◽  
Thermoregulatory Responses ◽  
Alpha Blockade ◽  
Stimulation Of

The involvement of the ventromedial hypothalamus (VMH) in thermoregulatory responses, which include heat production and heat loss responses, was investigated by the method of electrical stimulation. Electrical stimulation of the VMH caused a rise in rectal temperature, accompanied by the enhancement of heat production: O2 consumption and shivering. In addition, a reduction in heat loss was observed, including decreases in skin temperature (Ts), respiratory rate, and body surface area resulting from a huddled posture. In this study, stimulation of the lateral hypothalamus and other regions near the VMH had no effect on thermoregulatory responses. beta-Blocker (propranolol, 1 mg/kg iv) injected 20 min before stimulation lessened O2 consumption by approximately 10% and attenuated the reduction in Ts during VMH stimulation, whereas alpha-blockade (phentolamine, 1 mg/kg iv) was ineffective. These results indicate that most of the increase in O2 consumption during VMH stimulation was due to the occurrence of shivering but that some component of it could be due to nonshivering thermogenesis. They also indicate that the VMH, either directly or by converging influences, is involved in the activation of thermoregulatory responses to cold stress.

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