Heat Production and Quantitative Oxidation of Nutrients by Physical Activity in Pigs

Jakobsen, K.; Chwalibog, A.; Henckel, S.; Thorbek, G.

doi:10.1159/000177787

Cited by 9 publications

(12 citation statements)

References 5 publications

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“…1). A similar pattern was obtained by measuring activity in pigs [6] caused by iden tical principle applied in construction of the two respiration units [4][5][6] with a high inter nal ventilation rate.…”

Section: Discussionsupporting

confidence: 61%

“…The values of OXF/HE were 38 and 26% in the two periods in accordance with the observed variation in RQnp. The main part of the heat increment during and immediately after cycling was covered by an increased oxidation of carbohydrate as in the activity experiment with pigs [6].…”

Section: Discussionmentioning

confidence: 99%

“…The total HE and the heat from oxidation of carbo hydrate (OXCHO) and fat (OXF) were calculated by the same equations as used in the foregoing paper [6]: The amount of nitrogen excreted in urine (UN) in the different sections was calculated proportionately from a 24-hour collection.…”

Section: Calculationsmentioning

confidence: 99%

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Heat Production and Quantitative Oxidation of Nutrients by Physical Activity in Humans

Thorbek¹,

Chwalibog²,

Jakobsen³

et al. 1994

Ann Nutr Metab

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The effect of physical activity on heat production and oxidation of nutritients was measured by means of indirect calorimetry. The experiment included 6 male and 4 female healthy subjects who, during a 24-hour stay in the respiration chambers, performed, in the morning and afternoon, 15 min cycling with the total work of 6,750 kg m. Experiments were repeated twice (3- to 4-week interval) showing no differences between the gas exchange in the morning and afternoon and between first and second experiment. The gas exchange during cycling was about 4 times higher than during basal periods. The identical work of 66.2 kJ by cycling caused on average a heat increment of 309 kJ, yielding the mean energetic efficiency for the performed work of 0.22. The activity caused an increment of 11.5 g oxidized carbohydrate and 2.6 g oxidized fat.

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Section: Discussionsupporting

confidence: 61%

Section: Discussionmentioning

confidence: 99%

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Heat Production and Quantitative Oxidation of Nutrients by Physical Activity in Humans

Thorbek¹,

Chwalibog²,

Jakobsen³

et al. 1994

Ann Nutr Metab

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“…The higher level in the sow may be due to the bigger mass to be moved. Heat production and quantitative oxidation of nutrients by physical activity in pigs has been discussed by Jakobsen et al (1994). The constant HE with increasing progress of lactation appeared striking, as the feed intake and the milk production concomitantly increased, and changes of physical activity or heat production per kg DM of feed could not account for this.…”

Section: Discussionmentioning

confidence: 99%

Methodological considerations as to quantify nutrient and energy metabolism in lactating sows

Jakobsen¹,

Theil²,

Jørgensen³

2005

J. Anim. Feed Sci.

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Protein, fat, carbohydrate and energy metabolism were studied in 8 lactating sows with their litters. Intake of nutrients and energy and excretion in faeces, urine and milk were studied in digestibility and nitrogen (N) and carbon (C) balances, while indirect calorimetry was used to quantify heat (HE) and methane (CH 4 ) production. As the piglets have to join the sow during measurements total HE (sow + piglets) was measured. In order to separate total HE into sow HE and piglet HE different methods were used. The sow milk production was measured by deuterated water (D 2 O) dilution. By using doubly labelled water (D 2 18 O) in three piglets per litter, the CO 2 production of the piglets was measured simultaneously with milk production with high accuracy. The sow HE was measured from heart rate by implantation of a telemetric transmitter. In addition total HE could be separated into sow HE and piglet HE by dividing the gas exchange according to metabolic liveweight (LW, kg 0.75 ) of sow and piglets and by using factorial methods for sow and piglets. The physical activity of the sow was recorded by means of a photocell. Advantages and disadvantages by using the different methods are discussed.

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“…Indirect calorimetry has long since been successfully used for the calculation of heat production in animals and in humans (24,38,48). For the past decade, measurements of gas exchange have been used to calculate the oxidation of protein, carbohydrate, and fat in the intact body of different species (9,24,38). Oxygen consumption and CO 2 release were registered in WT and LXR␣␤ Ϫ/Ϫ mice before and after 3 wk of an HCD for 48 h in temperature-controlled (23°C) individual chambers (Fig.…”

Section: Increased Energy Expenditure and Net Dnl In Lxr␣␤mentioning

confidence: 99%

Liver X receptors regulate de novo lipogenesis in a tissue-specific manner in C57BL/6 female mice

Korach-André

Archer

Gabbi

et al. 2011

American Journal of Physiology-Endocrinology and Metabolism

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The liver X receptors (LXRs) play a key role in cholesterol and bile acid metabolism but are also important regulators of glucose metabolism. Recently, LXRs have been proposed as a glucose sensor affecting LXR-dependent gene expression. We challenged wild-type (WT) and LXR␣␤ Ϫ/Ϫ mice with a normal diet (ND) or a high-carbohydrate diet (HCD). Magnetic resonance imaging showed different fat distribution between WT and LXR␣␤ Ϫ/Ϫ mice. Surprisingly, gonadal (GL) adipocyte volume decreased on HCD compared with ND in WT mice, whereas it slightly increased in LXR␣␤ Ϫ/Ϫ mice. Interestingly, insulin-stimulated lipogenesis of isolated GL fat cells was reduced on HCD compared with ND in LXR␣␤ Ϫ/Ϫ mice, whereas no changes were observed in WT mice. Net de novo lipogenesis (DNL) calculated from V O2 and V CO2 was significantly higher in LXR␣␤ Ϫ/Ϫ than in WT mice on HCD. Histology of HCD-fed livers showed hepatic steatosis in WT mice but not in LXR␣␤ Ϫ/Ϫ mice. Glucose tolerance was not different between groups, but insulin sensitivity was decreased by the HCD in WT but not in LXR␣␤ Ϫ/Ϫ mice. Finally, gene expression analysis of adipose tissue showed induced expression of genes involved in DNL in LXR␣␤ Ϫ/Ϫ mice compared with WT animals as opposed to the liver, where expression of DNL genes was repressed in LXR␣␤ Ϫ/Ϫ mice. We thus conclude that absence of LXRs stimulates DNL in adipose tissue, but suppresses DNL in the liver, demonstrating opposite roles of LXR in DNL regulation in these two tissues. These results show tissue-specific regulation of LXR activity, a crucial finding for drug development. high carbohydrate; energy regulation; metabolism; insulin resistance OBESITY AND ASSOCIATED COMPLICATIONS such as cardiovascular diseases and diabetes represent a major health problem in Western countries. The molecular mechanisms behind metabolic disorders are poorly understood but typically involve deregulation of cholesterol, lipid, and carbohydrate metabolism as well as impaired insulin signaling. The principal function of insulin is to maintain blood glucose and nonesterified fatty acid (NEFA) concentrations nearly constant despite the fluctuations during dietary intake of carbohydrates and lipids. De novo lipogenesis (DNL), i.e., the synthesis of fatty acids from nonlipid substrates, mainly carbohydrates, is nutritionally regulated. Both glucose and insulin signaling pathways are engaged in response to dietary carbohydrates to synergistically induce expression of glycolytic and lipogenic genes in the liver (12).Liver and adipose tissue are the two main sites of DNL in mice (32, 46). In humans, DNL capacity of adipose tissue remains controversial. Diraison et al. (14) found that a highcarbohydrate diet (HCD) in humans does not upregulate DNL or expression of lipogenic genes in adipocytes, whereas hepatic DNL is increased two-to threefold. Letexier et al. (32) concluded that DNL is reduced in human adipose tissue compared with rodents due to a lower abundance of sterol-responsive element-binding protein-1c (SREBP-1c) protein (...

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Heat Production and Quantitative Oxidation of Nutrients by Physical Activity in Pigs

Cited by 9 publications

References 5 publications

Heat Production and Quantitative Oxidation of Nutrients by Physical Activity in Humans

Heat Production and Quantitative Oxidation of Nutrients by Physical Activity in Humans

Methodological considerations as to quantify nutrient and energy metabolism in lactating sows

Liver X receptors regulate de novo lipogenesis in a tissue-specific manner in C57BL/6 female mice

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