The Effect of Sweetness on the Efficacy of Carbohydrate Supplementation During Exercise in the Heat

2005 ◽  
Vol 30 (4) ◽  
pp. 379-391 ◽  
Author(s):  
James Carter ◽  
Asker E. Jeukendrup ◽  
David A. Jones
Keyword(s):  
Ambient Temperature ◽  
Key Words ◽  
Exercise Capacity ◽  
Rectal Temperature ◽  
Plasma Glucose ◽  
Prolonged Exercise ◽  
Carbohydrate Supplementation ◽  
Hot Environments ◽  
Carbohydrate Solution ◽  
Key Words Cycling

The aim of the present study was to investigate potential mechanisms responsible for the improvement in prolonged exercise capacity in hot environments with exogenous carbohydrate. Eight endurance-trained men ([Formula: see text]60.5 ± 2.4 ml kg−1•min−1, mean ± SE) cycled to exhaustion on three occasions at 60% [Formula: see text] at an ambient temperature of 35 °C. They ingested either a sweet 6.4% carbohydrate solution (SC), a nonsweet 6.4% carbohydrate solution (NSC), or water (W). Exercise capacity was significantly increased with SC and NSC compared to W, the improvements corresponding to 15.8% and 11.8%, respectively. No difference in exercise capacity was seen between SC and NSC solutions. Plasma glucose concentrations were higher during the SC and NSC trials compared to W, significantly so at 10 min and at fatigue. Rates of carbohydrate oxidation were higher in the SC and NSC trials, although the rates never declined below 2.1 ± 0.2 g•min−1 in the W trial. There was no difference in the rate of rise of rectal temperature between trials, but there was a trend for subjects to fatigue at higher temperatures during the two carbohydrate trials. In conclusion, exogenous carbohydrate, independent of sweetness, improves exercise capacity in the heat compared to water alone. Key words: cycling, thermoregulation, maltodextrin

EFFECT OF INTRARUMINAL INFUSION OF PROPIONIC ACID ON PLASMA METABOLITES IN GOATS

1984 ◽  
Vol 64 (5) ◽  
pp. 295-297 ◽  
Author(s):  
B. EMMANUEL ◽  
J. J. KENNELLY
Keyword(s):  
Key Words ◽  
Propionic Acid ◽  
Plasma Glucose ◽  
Milk Fat ◽  
Plasma Metabolites ◽  
Data Support

Effects of intraruminal infusion of propionic acid at 5.5 and 13.7 g/h on plasma metabolites have been investigated in goats fed a concentrate-roughage ration at 2-h intervals. Propionic acid increased plasma glucose and insulin concentrations, but did not change those of lactate, D(−)-3-hydroxybutyrate and prolactin. Data support the glucogenic theory in relation to low milk fat syndrome. Key words: Metabolites, plasma, goats, propionic acid

Heat balance, haematology and serum chemistry of layers under varying stocking density reared in locally fabricated metal-type cage system

2020 ◽  
Vol 40 (2) ◽  
pp. 92-103
Author(s):  
K. O. Bello ◽  
A. E. Adiatu ◽  
M. O. Osunlakin ◽  
O. O. Oni
Keyword(s):  
Relative Humidity ◽  
Ambient Temperature ◽  
Rectal Temperature ◽  
Heat Balance ◽  
Total Protein ◽  
Stocking Density ◽  
Fabricated Metal ◽  
Cage System ◽  
Chemical Measurements ◽  
Metal Type

One hundred and thirty five 18weeks old Bovans Nera Black strain pullets were used in a 10week study to determine their heat balance and blood profile under varying stocking density in locally fabricated metal-type cage system. The cages were stocked 2, 3 and 4birds/cell. Daily ambient temperature and relative humidity of the cage and rectal temperature of the birds were taken and heat balance calculated. Record of Packed cell volume (PCV), Haemoglobin concentration (Hb), Red blood cell (RBC), White blood count (WBC) and differential of the birds were taken at beginning and end of the study for the haematological indices while blood glucose, total protein, Albumin and blood urea were taken for the bio-chemical measurements. Ambient temperature, relative humidity, and heat balance showed no significant (P>0.05) difference with cage stocking density. Cage stocking density had significant (P<0.05) effect on rectal temperature of layers. Bird stocked 3/cell recorded the least (41.14oC) rectal temperature while those stocked 4/cell recorded the highest (41.27oC). All the haematological parameters of the birds were not significantly (P>0.05) influenced by stocking density of the cage type. Bio-chemical measurements were not significantly (P>0.05) different among layers under varying stocking density of the cage except total protein (P<0.05). Layers stocked 4/cell recorded highest (5.22g/dl) total protein while those stocked 3/cell had the least value (4.37g/dl). However, the values were within the normal range recommended for healthy chicken. The study concluded that locally fabricated metal-type battery cage could be used to rear layers and stocking density of 3birds/cell is ideal without compromising the welfare of the birds.

Effect of ambient temperature on protein breakdown during prolonged exercise

1988 ◽  
Vol 64 (2) ◽  
pp. 550-555 ◽  
Author(s):  
D. G. Dolny ◽  
P. W. Lemon
Keyword(s):  
Ambient Temperature ◽  
Prolonged Exercise ◽  
Respiratory Exchange Ratio ◽  
Protein Breakdown ◽  
Protein Utilization ◽  
Post Exercise ◽  
Ambient Temperatures ◽  
Environmental Temperatures ◽  
Male Subjects ◽  
H Protein

Male subjects (n = 8) cycled for 90 min in 5, 20, and 30 degrees C environments. Rectal (Tre), chest, and thigh temperatures, O2 consumption (VO2), respiratory exchange ratio (R), and venous concentrations of glucose, free fatty acids (FFA), urea N, lactic acid (LA), norepinephrine (NE), epinephrine (E), and cortisol (C) were measured before, during, and after exercise. Urea N excretion was measured in 72 h of nonexercise, in 72 h of exercise (exercise day + 2 post-exercise days) urine samples, and in exercise sweat. Calculated 72-h protein utilization (means +/- SE) was significantly greater (P less than 0.05) for the 5 (86.9 +/- 27.1 g) and 20 (82.9 +/- 22.7 g) compared with 30 degrees C (34.01 +/- 19.1 g) trial. Regardless of ambient temperature exercise increased the venous concentration of C, E, and NE. These catabolic hormones were greatest in 5, lowest in 20, and intermediate in 30 degrees C. Exercise Tre and VO2 were greatest in the 30 degrees C environment. Venous FFA concentration was significantly higher and R significantly lower in 5 vs. 20 or 30 degrees C, and venous LA concentration was significantly greater in 30 vs. 20 or 5 degrees C. Although these results indicate that exercise protein breakdown is affected by ambient temperatures, the mechanism of action is not due solely to circulating NE, E, and C. Differences in venous FFA and LA across environmental temperatures suggest that alterations in carbohydrate and fat metabolism may have contributed to the observed variable protein utilization.

Effect of menstrual cycle phase on carbohydrate supplementation during prolonged exercise to fatigue

2000 ◽  
Vol 88 (2) ◽  
pp. 690-697 ◽  
Author(s):  
Stephen P. Bailey ◽  
Cristine M. Zacher ◽  
Karen D. Mittleman
Keyword(s):  
Fatty Acids ◽  
Menstrual Cycle ◽  
Prolonged Exercise ◽  
Cycle Phase ◽  
Time To Exhaustion ◽  
Menstrual Cycle Phase ◽  
Exercise Time ◽  
Carbohydrate Supplementation ◽  
Plasma Tyrosine ◽  
Placebo Drink

The effects of menstrual cycle phase and carbohydrate (CHO) supplementation were investigated during prolonged exercise. Nine healthy, moderately trained women cycled at 70% peak O2 consumption until exhaustion. Two trials were completed during the follicular (Fol) and luteal (Lut) phases of the menstrual cycle. Subjects consumed 0.6 g CHO ⋅ kg body wt− 1 ⋅ h− 1(5 ml/kg of a 6% CHO solution every 30 min beginning at min 30 of exercise) or a placebo drink (Pl) during exercise. Time to exhaustion during CHO increased from Pl values ( P < 0.05) by 14.4 ± 8.5 (Fol) and 11.4 ± 7.1% (Lut); no differences were observed between menstrual cycle phases. CHO attenuated ( P < 0.05) the decrease in plasma glucose and insulin and the increase in plasma free fatty acids, tryptophan, epinephrine, and cortisol observed during Pl for both phases. Plasma alanine, glutamine, proline, and isoleucine were lower ( P < 0.05) in Lut than in Fol phase. CHO resulted in lower ( P < 0.05) plasma tyrosine, valine, leucine, isoleucine, and phenylalanine. These results indicate that the menstrual cycle phase does not alter the effects of CHO supplementation on performance and plasma levels of related substrates during prolonged exercise.

Cholecystokinin reduces body temperature in vehicle- but not capsaicin-pretreated rats

1992 ◽  
Vol 263 (6) ◽  
pp. R1215-R1221 ◽  
Author(s):  
E. H. South
Keyword(s):  
Food Intake ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Rectal Temperature ◽  
Neural Substrates ◽  
Systemic Administration ◽  
Capsaicin Application ◽  
Presence And Absence ◽  
Sensory Fibers ◽  
Maximal Suppression

Systemic administration of cholecystokinin C-terminal octapeptide (CCK-8) decreases body temperature. However, it remains unclear whether reduction of body temperature is concomitant with suppression of food intake at CCK-8 doses that approach physiological levels. We examined rectal temperature after intraperitoneal CCK-8, 4 micrograms/kg, both in the presence and absence of a preferred food. We found that rectal temperature was significantly reduced by CCK-8 in both conditions and that the reduction of temperature coincided with the time of maximal suppression of food intake by CCK-8. In rats pretreated systemically with 25 or 175 mg/kg of the sensory neurotoxin capsaicin, both suppression of food intake and reduction of body temperature were significantly attenuated or abolished. The 25 mg/kg capsaicin treatment did not alter corneal chemosensitivity or the ability of rats to maintain normothermia at elevated ambient temperature, suggesting that capsaicin damage to neural substrates mediating CCK-8-induced reduction of body temperature 1) did not generalize to cephalic or peripheral warm-sensitive structures, and 2) was limited to fine sensory fibers accessible to intraperitoneal capsaicin application.

Changes in plasma glucose, FFA, corticosterone, and thyroxine in He-O2-induced hypothermia

1977 ◽  
Vol 42 (5) ◽  
pp. 694-698 ◽  
Author(s):  
L. C. Wang ◽  
R. E. Peter
Keyword(s):  
Fatty Acids ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Plasma Glucose ◽  
Spontaneous Recovery ◽  
Male Rats ◽  
Regulatory Mechanisms ◽  
Induced Hypothermia ◽  
Blood Samples ◽  
Metabolic Substrates

Unanesthetized, male rats were exposed to normal air (NA), or NA and a 4 h-exposure of He-O2 (79% helium, 21% oxygen) at ambient temperature (Ta) of 22 or - 10 degrees C. Blood samples from each individual were taken from a chronically implanted carotid cannula at 1) preexposure, 2) during exposure, 3) 2.5 h after exposure, and 4) 19–20 h after exposure. Exposure to He-O2 at 22 degrees C caused an increase in plasma free fatty acids (FFA) and corticosterone of 45% and 49%, respectively, with little change in plasma glucose and thyroxine. Exposure to He-O2 at 10 degrees C for 3 h invariably induced hypothermia with body temperature (Tb) decreased to 23.7 +- 0.5 degrees C (N = 10). During hypothermia, plasma glucose, FFA, and corticosterone were significantly higher (P LESS THAN 0.05) than those at preexposure and those after exposure to NA at -10 degrees C. During spontaneous recovery from hypothermia, at Ta = 19 degrees C and NA, glucose, corticosterone, and thyroxine returned to normal, but FFA remained significantly higher than at preexposure. The ability of animals to rewarm spontaneously from hypothermia and the quick return of metabolic substrates and hormones to normal after rewarming indicates the preservation of regulatory mechanisms for metabolism at depressed Tb when hypothermia is induced by He-O2 and cold.

The effect of increased rectal temperature on nitrogen metabolism in Brahman cross and Shorthorn X Hereford steers fed on lucerne chaff

1969 ◽  
Vol 20 (3) ◽  
pp. 607 ◽  
Author(s):  
JE Vercoe
Keyword(s):  
Heat Treatment ◽  
Ambient Temperature ◽  
Nitrogen Metabolism ◽  
Rectal Temperature ◽  
Feed Intake ◽  
Dry Matter ◽  
Water Losses ◽  
Breed Difference ◽  
Nitrogen Intake ◽  
Urinary Nitrogen

A study was made of the effect on nitrogen metabolism of increasing the rectal temperature of Brahman cross and British steers on controlled feed intake. When the rectal temperature of the British steers was 1.3 °C higher than that of the Brahman cross steers, they excreted 13.5 g urinary nitrogen per day more than the Brahman cross. When the Brahman cross steers had a rectal temperature 1.3 °C higher than the British, they excreted 8.7 g urinary nitrogen per day more than the British steers. At the same nitrogen intake there was no significant breed difference in the increase in urinary nitrogen per degree rise in rectal temperature. Increasing the rectal temperature had a small effect on appetite but did not affect the apparent nitrogen digestibility; the concentration of nitrogen in the faecal dry matter was higher under the heat treatment. The ambient temperature at which rectal temperatures were increased by 1.3 °C was about 31°C for the British steers and 45° for the Brahman cross steers. At the increased rectal temperature the Brahman cross steers drank significantly more water than the British steers although faecal and urinary water losses were similar.

Fat-tailed Awassi and German Mutton Merino sheep under semi-arid conditions: 3. Body temperatures and panting rate

1977 ◽  
Vol 89 (2) ◽  
pp. 399-405 ◽  
Author(s):  
A. A. Degen
Keyword(s):  
Ambient Temperature ◽  
Rectal Temperature ◽  
Brain Temperature ◽  
External Auditory Meatus ◽  
Merino Sheep ◽  
Arid Conditions ◽  
Breed Difference ◽  
The Mean ◽  
Skin Temperatures ◽  
Semi Arid

SummaryRectal, external auditory meatus and skin temperatures and panting rates were measured in native fat-tailed Awassi and imported German Mutton Merino (GMM) sheep. The Awassi evolved under desert conditions, have a localized fat deposit, coarse carpet wool, long pendulous ears and long, spiral horns (males). In contrast, the GMM evolved under temperate conditions, have well-distributed fat, medium fine wool, short, straight ears and are polled. The study was carried out during the summer in the northern part of the Negev desert.The mean daily rectal temperature fluctuation was higher (P < 0·01) in the GMM than in the Awassi (1·78 °C v. 1·08 °C). The external auditory meatus temperature was lower than the rectal temperature by 1·5 °C in the GMM and by 1·7 °C in the Awassi, indicating a cooler brain temperature. The maximum skin temperature was similar to the maximum rectal temperature in both breeds, thus sweating was of little importance. The panting rate of the GMM increased fivefold (40·6–199·4 pants/min) whilst the rate of the Awassi increased fourfold (35·3–135·0 pants/min). There was no between-breed difference in either the rectal temperature or panting rate until 25–30 °C ambient temperature and it is thought that the higher rectal temperature of the GMM at this ambient temperature might have triggered off the higher panting rate. It seems that the GMM use panting to a greater extent than the Awassi whereas the Awassi dissipate heat through the skin more efficiently than the GMM. It is concluded that both breeds are thermostable, much of the between-breed difference in rectal temperature can be attributed to their anatomical differences.

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