Application of 13CO2 measurements to the estimation of energy expenditure in goats

1992 ◽  
Vol 72 (2) ◽  
pp. 245-252 ◽  
Author(s):  
T. Sahlu ◽  
N. Jacquemet ◽  
H. Carneiro ◽  
S. P. Hart ◽  
P. D. Klein
Keyword(s):  
Stable Isotopes ◽  
Energy Expenditure ◽  
Energy Requirement ◽  
Serum Samples ◽  
Body Weights ◽  
Saliva Collection ◽  
Ad Libitum ◽  
Time Required ◽  
Similar Body ◽  
Free Ranging

The use and limitations of 13C stable isotopes as tracers in animal experimentation was investigated using 13C-labeled bicarbonate to estimate CO2 production and energetic requirement of free-ranging goats. Goats were fed wheat hay (Triticum aestivum; C3) or Old World Bluestem hay (Bothriochloa caucasica; C4; OWBS) ad libitum for 21 d. Parotid salivary ducts were cannulated for saliva collection. Isotopic bicarbonate (13C) was infused at a constant rate into the peritoneal cavity. In exp. 1, saliva samples were obtained at successive 2-h periods for 20 h to establish the time to achieve equilibrium. The half-life of bicarbonate was 2.9 h for animals consuming the wheat diet and 4.1 h (P < 0.06) for animals consuming OWBS diet. The time required to reach equilibrium was 12 h for animals on the wheat diet and 16 h for animals on OWBS diet. The error in the technique arising from animals consuming C3 vs. C4 species (which have different endogenous 13C contents) was studied in exp. 2. If species composition (C3 vs. C4) of the diet remains constant within 10%, the error is negligible. In exp. 3, estimation of CO2 production from continuous saliva samples had a lower coefficient of variation (6.3 vs. 10.0%) than measurements based on spot serum samples. Energy expenditure of goats in stalls consuming hay ad libitum was similar to that of ad-libitum-fed sheep at similar body weights. The 13C methodology appears to be a promising method for measuring energy expenditure of grazing animals. Key words: Energy requirement, stable isotopes, carbon dioxide, sodium bicarbonate

scholarly journals Quantifying the free living energy exchanges of Arctic ungulates with stable isotopes

Rangifer ◽  
2000 ◽  
Vol 20 (2-3) ◽  
pp. 59 ◽  
Author(s):  
Paul Haggarty
Keyword(s):  
Physical Activity ◽  
Energy Expenditure ◽  
Energy Requirement ◽  
Ecological Impact ◽  
The Arctic ◽  
Unknown Parameters ◽  
Free Living ◽  
Doubly Labelled Water ◽  
Energy Exchanges ◽  
Free Ranging

When natural diets meet an animal's requirement for energy, other essential nutrients will usually be supplied in amounts at least sufficient for survival. Knowledge of the energy requirements of free ranging species under typical conditions are important in assessing both their nutritional needs and their ecological impact. The doubly labelled water (DLW) method is currently the most promising objective field methodology for estimating free living energy expenditure but expenditure is only equal to the energy requirement when an animal is in energy balance. Reproduction and seasonal cycles of fat deposition and utilization represent significant components of the energy budget of arctic ungulates but the information gained in the course of a typical DLW study may be used to estimate processes such as milk output and fat storage and mobilization in order to predict requirements from expenditure. The DLW method has been exhaustively validated under highly controlled conditions and the introduction of innovations such as faecal sampling for the estimation of body water isotopic enrichment, the availability of appropriate correction factors and stoichiometrics for known sources of error, and iterative calculation of unknown parameters, have produced a methodology suitable for use in truly free ranging species. The few studies carried out so far in arctic ungulates indicate that previous predictions have generally underestimated the true level of expenditure, that there is considerable between animal variation in the level of expenditure and that this is largely determined by physical activity. The disadvantages of the DLW methodology are that it remains expensive and the isotope analysis is technically demanding. Furthermore, although DLW can provide an accurate value for free living energy expenditure, it is often important to have information on the individual components of expenditure, for example the relative contribution of physical activity and thermoregulatory thermogenesis, in order to interpret the values for overall expenditure. For these reasons the most valuable use of the DLW method in the field may be to validate factorial models and other approaches so that they may be used with confidence. Additional important information on the energy exchanges of free ranging animals may be obtained from other stable isotope methodologies. In addition to the use of the isotopes 2H and lsO in the DLW method, natural variations in the abundance of "C and 15N in the arctic environment may be exploited to study diet selection in truly free living arctic ungulates.

scholarly journals The effects of physical exercise on metabolic rate and dietary-induced thermogenesis

1982 ◽  
Vol 47 (2) ◽  
pp. 173-181 ◽  
Author(s):  
M. Gleeson ◽  
J. F. Brown ◽  
J. J. Waring ◽  
M. J. Stock
Keyword(s):  
Body Weight ◽  
Energy Metabolism ◽  
Energy Expenditure ◽  
Physical Exercise ◽  
Metabolic Rate ◽  
Energy Requirement ◽  
Resting Metabolic Rate ◽  
Metabolizable Energy ◽  
Physical Work ◽  
Similar Body

1. The energy metabolism of ad lib.-fed adult male Wistar rats receiving daily running exercise (0·9 km/d; 8° incline) on a motor-driven treadmill, over a period of 56 d, was compared with that of sedentary ad lib.-fed rats and sedentary restricted-fed rats of similar body-weight (approximately 420 g).2. The metabolizable energy of the diet (Oxoid 41B) was 11·44 ± 0·05 kJ/g. This value was not affected by restricted feeding (70% ad lib.), exercise training or exercise itself.3. Exercise-trained rats ate 5% more food than the sedentary ad lib.-fed rats but their equilibrium body-weight was 60 g lower than that of the latter group.4. Resting metabolic rate, measured over 22 h in a respiration chamber was increased by 10% in exercise-trained animals.5. Feeding increased energy expenditure (dietary-induced thermogenesis) and this effect was potentiated by performance of an exercise task.6. Exercise-trained rats exhibited anticipatory rises in energy expenditure (approximately 40%) when placed on a stationary treadmill.7. Treadmill work increased energy expenditure by a factor of 1·9–2·4.8. The energy cost of the exercise, determined by respiration calorimetry was 66–80 J/g per km. These energy costs did not account for all the differences observed in food energy consumption of exercise-trained and sedentary rats of equal body-weight.9. It is concluded that regular physical exercise increases energy expenditure by factors additional to the energy requirement directly related to the physical work. These factors include an increased resting metabolic rale in exercise-trained rats, increased dietary thermogenesis induced by exercise and anticipatory increases in energy metabolism during the period preceding exercise.

Prevention of genetic fa/fa obesity with an ephedrine-methylxanthines thermogenic mixture

1987 ◽  
Vol 252 (3) ◽  
pp. R507-R513
Author(s):  
A. G. Dulloo ◽  
D. S. Miller
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Energy Balance ◽  
Energy Expenditure ◽  
Food Restriction ◽  
Energy Deposition ◽  
Energetic Efficiency ◽  
Ad Libitum ◽  
Similar Body ◽  
Body Energy

A thermogenic mixture containing ephedrine and methylxanthines was administered to 8-wk-old genetically obese fa/fa rats (O-E/Mx group) for a period of 15 wk. Their energy balance and the final body composition were compared with an untreated ad libitum-fed (O-AL) group, as well as to other fa/fa obese animals that were either pair fed to lean controls (O-PF group), or that were food restricted to such an extent they maintained a similar body weight to that of lean animals (O-WF group). Energy intake was elevated above lean or O-PF levels by approximately 27 and 10% in the O-AL and O-E/Mx groups, respectively, but lower by 18% in the O-WF group. Energy expenditure, compared with the lean values, was 10% higher in both the O-AL and O-E/Mx groups, but reduced by 13 and 30% in the O-PF and O-WF groups, respectively. The gain in body energy and the efficiency of energy deposition remained elevated above the lean values by 2.3- to 3.5-fold in the O-AL, O-PF, and O-WF groups but were reduced to lean levels in the O-E/Mx groups. These studies indicate that, unlike food restriction, the ephedrine-methylxanthine mixture prevents or arrests the development of the obesity in the fa/fa mutant by normalizing their energetic efficiency to that of the lean.

scholarly journals Metabolic, gastrointestinal, and CNS neuropeptide effects of brain leptin administration in the rat

1999 ◽  
Vol 276 (5) ◽  
pp. R1425-R1433 ◽  
Author(s):  
Gertjan van Dijk ◽  
Randy J. Seeley ◽  
Todd E. Thiele ◽  
Mark I. Friedman ◽  
Hong Ji ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Body Weight ◽  
Energy Expenditure ◽  
Neuropeptide Y ◽  
Caloric Restriction ◽  
Resting Energy Expenditure ◽  
Corticotropin Releasing Hormone ◽  
Plasma Fatty Acids ◽  
The Third ◽  
Ad Libitum

To investigate whether brain leptin involves neuropeptidergic pathways influencing ingestion, metabolism, and gastrointestinal functioning, leptin (3.5 μg) was infused daily into the third cerebral ventricular of rats for 3 days. To distinguish between direct leptin effects and those secondary to leptin-induced anorexia, we studied vehicle-infused rats with food available ad libitum and those that were pair-fed to leptin-treated animals. Although body weight was comparably reduced (−8%) and plasma glycerol was comparably increased (142 and 17%, respectively) in leptin-treated and pair-fed animals relative to controls, increases in plasma fatty acids and ketones were only detected (132 and 234%, respectively) in pair-fed rats. Resting energy expenditure (−15%) and gastrointestinal fill (−50%) were reduced by pair-feeding relative to the ad libitum group, but they were not reduced by leptin treatment. Relative to controls, leptin increased hypothalamic mRNA for corticotropin-releasing hormone (CRH; 61%) and for proopiomelanocortin (POMC; 31%) but did not reduce mRNA for neuropeptide Y. These results suggest that CNS leptin prevents metabolic/gastrointestinal responses to caloric restriction by activating hypothalamic CRH- and POMC-containing pathways and raise the possibility that these peripheral responses to CNS leptin administration contribute to leptin’s anorexigenic action.

Determining the least time required for measuring energy expenditure in premature neonates

2007 ◽  
Vol 35 (1) ◽  
Author(s):  
Maria E.L. Moreira ◽  
Alan A. Vieira ◽  
Fernanda V. Mendes Soares ◽  
Renata Bastos Lopes ◽  
Plinio Gomes ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Premature Neonates ◽  
Time Required

scholarly journals Inactivation of the adrenergic receptor β2 disrupts glucose homeostasis in mice

2014 ◽  
Vol 221 (3) ◽  
pp. 381-390 ◽  
Author(s):  
Gustavo W Fernandes ◽  
Cintia B Ueta ◽  
Tatiane L Fonseca ◽  
Cecilia H A Gouveia ◽  
Carmen L Lancellotti ◽  
...  
Keyword(s):  
Body Weight ◽  
Energy Expenditure ◽  
Glucose Homeostasis ◽  
High Fat Diet ◽  
Liver Steatosis ◽  
Mrna Levels ◽  
High Fat ◽  
Adaptive Thermogenesis ◽  
Brown Adipose ◽  
Similar Body

Three types of beta adrenergic receptors (ARβ1–3) mediate the sympathetic activation of brown adipose tissue (BAT), the key thermogenic site for mice which is also present in adult humans. In this study, we evaluated adaptive thermogenesis and metabolic profile of a mouse withArβ2knockout (ARβ2KO). At room temperature, ARβ2KO mice have normal core temperature and, upon acute cold exposure (4 °C for 4 h), ARβ2KO mice accelerate energy expenditure normally and attempt to maintain body temperature. ARβ2KO mice also exhibited normal interscapular BAT thermal profiles during a 30-min infusion of norepinephrine or dobutamine, possibly due to marked elevation of interscapular BAT (iBAT) and ofArβ1, andArβ3mRNA levels. In addition, ARβ2KO mice exhibit similar body weight, adiposity, fasting plasma glucose, cholesterol, and triglycerides when compared with WT controls, but exhibit marked fasting hyperinsulinemia and elevation in hepaticPepck(Pck1) mRNA levels. The animals were fed a high-fat diet (40% fat) for 6 weeks, ARβ2KO mice doubled their caloric intake, accelerated energy expenditure, and inducedUcp1expression in a manner similar to WT controls, exhibiting a similar body weight gain and increase in the size of white adipocytes to the WT controls. However, ARβ2KO mice maintain fasting hyperglycemia as compared with WT controls despite very elevated insulin levels, but similar degrees of liver steatosis and hyperlipidemia. In conclusion, inactivation of the ARβ2KO pathway preserves cold- and diet-induced adaptive thermogenesis but disrupts glucose homeostasis possibly by accelerating hepatic glucose production and insulin secretion. Feeding on a high-fat diet worsens the metabolic imbalance, with significant fasting hyperglycemia but similar liver structure and lipid profile to the WT controls.

Prospective study of hepatitis C virus infection in hemodialysis patients by monthly analysis of HCV RNA and antibodies

2003 ◽  
Vol 49 (8) ◽  
pp. 503-507 ◽  
Author(s):  
Regina Moreira ◽  
João Renato Rebello Pinho ◽  
Jorge Fares ◽  
Isabel Takano Oba ◽  
Maria Regina Cardoso ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hemodialysis Patients ◽  
Hcv Infection ◽  
Hcv Rna ◽  
Hepatitis C Virus Infection ◽  
Serum Samples ◽  
Hcv Genotypes ◽  
High Prevalence ◽  
Time Required

The aims of this study were to (i) evaluate the prevalence and the incidence of hepatitis C virus (HCV) infection in hemodialysis patients in two different centers in São Paulo (Brazil), (ii) determine the time required to detect HCV infection among these patients by serology or PCR, (iii) establish the importance of alanine aminotransferase determination as a marker of HCV infection, and (iv) identify the HCV genotypes in this population. Serum samples were collected monthly for 1 year from 281 patients admitted to hospital for hemodialysis. Out of 281 patients, 41 patients (14.6%) were HCV positive; six patients seroconverted during this study (incidence = 3.1/1000 person-month). In 1.8% (5/281) of cases, RNA was detected before the appearance of antibodies (up to 5 months), and in 1.1% (3/281) of cases, RNA was the unique marker of HCV infection. The genotypes found were 1a, 1b, 3a, and 4a. The presence of genotype 4a is noteworthy, since it is a rare genotype in Brazil. These data pointed out the high prevalence and incidence of HCV infection at hemodialysis centers in Brazil and showed that routine PCR is fundamental for improving the detection of HCV carriers among patients undergoing hemodialysis.Key words: HCV genotypes, hemodialysis, hepatitis C, PCR, prevalence, incidence.

Noninvasive Saliva Collection for DNA Analyses From Free-Ranging Tibetan Macaques (Macaca thibetana)

2012 ◽  
Vol 74 (11) ◽  
pp. 1064-1070 ◽  
Author(s):  
N. D. SIMONS ◽  
J. G. LORENZ ◽  
L. K. SHEERAN ◽  
J. H. LI ◽  
D. P. XIA ◽  
...  
Keyword(s):  
Macaca Thibetana ◽  
Dna Analyses ◽  
Saliva Collection ◽  
Free Ranging

scholarly journals Leptin Responsiveness in Chronically Decerebrate Rats

Endocrinology ◽  
2007 ◽  
Vol 148 (10) ◽  
pp. 4623-4633 ◽  
Author(s):  
Ruth B. S. Harris ◽  
Timothy J. Bartness ◽  
Harvey J. Grill
Keyword(s):  
Energy Expenditure ◽  
Body Fat ◽  
Serum Testosterone ◽  
Control Group ◽  
Energy Status ◽  
Lower Serum ◽  
Peripheral Tissues ◽  
Leptin Receptors ◽  
Ad Libitum ◽  
Ad Libitum Intake

Peripheral infusions of physiological doses of leptin decrease body fat mass, but it is not known whether this results from direct effects on peripheral tissue or activation of central leptin receptors. In this study, we infused chronically decerebrate (CD) rats, in which the forebrain was surgically isolated from the caudal brainstem, with 60 μg leptin/d or PBS for 14 d from ip mini-osmotic pumps. The CD rats were tube fed an amount of food equivalent to the intake of ad libitum-fed intact controls or 75% of this amount to account for their reduced energy expenditure. Control rats fed ad libitum or tube fed 75, 100, or 125% of their ad libitum intake also were peripherally infused with leptin or PBS. CD rats had a lower serum testosterone, energy expenditure, and lean body mass compared with controls but had increased levels of adiponectin and leptin and were obese. Leptin increased body fat and decreased energy expenditure during the light period in 100%-fed CD rats, but not 75%-fed CD rats. Leptin decreased body fat of ad libitum- and 100%-fed but not 75%-fed or 125%-fed intact controls. Energy expenditure did not change in any control group. These results show that leptin can change body fat independent of a change in food intake or energy expenditure, that the forebrain normally prevents leptin from inhibiting energy expenditure through mechanisms initiated in the caudal brainstem or peripheral tissues, and that the leptin response in both intact and CD rats is determined by the energy status of the animal.

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