Non-invasive 13C bicarbonate tracer technique for measuring energy expenditure in men – A pilot study

Junghans, P.; Jentsch, W.; Derno, M.

doi:10.1016/j.eclnm.2008.01.001

Cited by 18 publications

(31 citation statements)

References 23 publications

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“…In previous studies, RQ values were found to be 0.85 in fasted humans (Junghans et al, 2008) and in fasted bulls (Junghans et al, 2007). For ponies fed simultaneously with administration of 13 C-bicarbonate (similar to T 0 in this study) RQ values of 0.79 were found, independent of administration route (IV or oral; Jensen et al, 2015).…”

Section: Discussionsupporting

confidence: 77%

“…Previous studies have reported the RF to be between 0.69 and 0.77 (Prieto et al, 2001;Junghans et al, 2007;Junghans et al, 2008;Larsson et al, 2014) or as high as 0.94 in dogs that were stressed/active during the measurements (Larsson et al, 2014). In the present experiment, administration route did not affect the RF in contrast to the results by Jensen et al (2015), where IV and oral administration of 13 C-bicarbonate resulted in RF values of 0.69 and 0.76, respectively.…”

Section: Discussioncontrasting

confidence: 73%

“…This is in agreement with the present results, where an average RQ of 0.81 was found regardless of administration route. The average RQ Figure 3 Effect of feeding 3 h before (T − 3 ), at the same time (T 0 ) or 3 h after (T + 3 ) a dose of 13 C-bicarbonate on O 2 consumption (l/kg BW per day), CO 2 production (l/kg BW per day) and respiratory quotient (RQ) measured hourly by indirect calorimetry for 6 h. must be estimated better than with 10% error to avoid erroneous estimation of EE (Junghans et al, 2008). An error of +0.1 in absolute RQ units (if the 'true' RQ is assumed to be 0.81) would underestimate EE with 8.5% in the present experiment, which is in accordance with Junghans et al (2007) and Jensen et al (2015), who, with a similar error in RQ, estimated the error in EE to be 8% to 9% in bulls and ponies, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…The 13 C-BT has successfully been used to estimate EE in humans (Junghans et al, 2008) and different animal species, including goats (Junghans et al, 1997;Prieto et al, 2001), bulls (Junghans et al, 2007), dogs (Larsson et al, 2014) and it has been validated against IC in ponies (Jensen et al, 2015). Administration of 13 C-bicarbonate has been done as a single intravenous (IV) bolus dose (Junghans et al, 2007;Jensen et al, 2015) or by continuous IV infusion (Prieto et al, 2001;Urschel et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Administration of 13 C-bicarbonate has been done as a single intravenous (IV) bolus dose (Junghans et al, 2007;Jensen et al, 2015) or by continuous IV infusion (Prieto et al, 2001;Urschel et al, 2009). However, oral administration of 13 C-bicarbonate has also been used (Junghans et al, 2008;Larsson et al, 2014;Jensen et al, 2015), meaning that the 13 C-BT may be used as a non-invasive method for measuring CO 2 production and hence EE.…”

Section: Introductionmentioning

confidence: 99%

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The effect of feeding on CO2 production and energy expenditure in ponies measured by indirect calorimetry and the 13C-bicarbonate technique

Jensen

Kyrstein

Junghans

et al. 2015

Animal

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Energy expenditure (EE) can be estimated based on respiratory gas exchange measurements, traditionally done in respiration chambers by indirect calorimetry (IC). However, the 13 C-bicarbonate technique ( 13 C-BT) might be an alternative minimal invasive method for estimation of CO 2 production and EE in the field. In this study, four Shetland ponies were used to explore the effect of feeding on CO 2 production and EE measured simultaneously by IC and 13 C-BT. The ponies were individually housed in respiration chambers and received either a single oral or intravenous (IV) bolus dose of 13 C-labelled sodium bicarbonate (NaH 13 CO 3 ). The ponies were fed haylage 3 h before ( T − 3 ), simultaneously with ( T 0 ) or 3 h after ( T + 3 ) administration of 13 C-bicarbonate. The CO 2 produced and O 2 consumed by the ponies were measured for 6 h with both administration routes of 13 C-bicarbonate at the three different feeding times. Feeding time affected the CO 2 production ( P < 0.001) and O 2 consumption ( P < 0.001), but not the respiratory quotient (RQ) measured by IC. The recovery factor (RF) of 13 C in breath CO 2 was affected by feeding time ( P < 0.01) and three different RF were used in the calculation of CO 2 production measured by 13 C-BT. An average RQ was used for the calculations of EE. There was no difference between IC and 13 C-BT for estimation of CO 2 production. An effect of feeding time ( P < 0.001) on the estimated EE was found, with higher EE when feed was offered ( T 0 and T + 3 ) compared with when no feed was available ( T − 3 ) during measurements. In conclusion, this study showed that feeding time affects the RF and measurements of CO 2 production and EE. This should be considered when the 13 C-BT is used in the field. IV administration of 13 C-bicarbonate is recommended in future studies with horses to avoid complex 13 C enrichment-time curves with maxima and shoulders as observed in several experiments with oral administration of 13 C-bicarbonate.Keywords: 13 C-bicarbonate, indirect calorimetry, energy expenditure, pony ImplicationsEnergy expenditure (EE) can be estimated based on measurements of respiratory gas exchange. This is traditionally done by indirect calorimetry in respiration chambers. However, the horse has to be confined to the chamber during measurements, which might affect its normal behaviour. Moreover, this technique requires expensive research facilities and skilled personnel. The minimal invasive stable isotope 13 C technique for measuring EE in the field was evaluated successfully in ponies. The present study developed this technique further and the results provide new information on how it can be used under field conditions.

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Section: Discussionsupporting

confidence: 77%