Techniques in energy metabolism studies and their limitations

Kl, Blaxter

doi:10.1079/pns19670016

Cited by 36 publications

(14 citation statements)

References 17 publications

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“…c,d). In general, the post‐absorptive state for large herbivores has been previously established to occur after 72 h of fasting (Marston, ; Blaxter, ). In this study, the estimated critical time when methane production was statistically equal to zero was at 31 h of fasting for Saanen goats and at 40 h for Anglo Nubian goats.…”

Section: Resultsmentioning

confidence: 99%

Fasting heat production of Saanen and Anglo Nubian goats measured using open‐circuit facemask respirometry

Fernandes

Lima

Almeida

et al. 2016

Animal Physiology Nutrition

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This study aimed to establish the heat production (HP) of Saanen and Anglo Nubian goats at absorptive (feeding) and at post-absorptive (fasting) statuses to determine the adequate period of fasting required for the measurement of basal metabolism. Gas exchange was recorded via open-circuit facemask respirometry. Six non-lactating and non-pregnant goats of each breed, Saanen (49.2 ± 3.2 kg of body weight, BW) and Anglo Nubian (64.0 ± 3.0 kg BW), were placed in individual pens with ad libitum access to the same total mixed ration. After a 3-day feeding period, the animals were subjected to fasting (no feed), and the gas exchange measurement was performed for 30 min at 0, 12, 20, 36, 44, 60 and 68 h after fasting. The daily HP of the Saanen and Anglo Nubian goats averaged 557.4 ± 38.7 and 357.1 ± 35.3 kJ/kg BW day respectively. During fasting, the methane production decreased exponentially in both breeds, and the critical time when methane production was statistically equal to zero was at 31 h of fasting for the Saanen goats and at 40 h for the Anglo Nubian goats. The daily HP and respiratory exchange rate during fasting decreased up to 60 h. Taken together, our results suggest that the ideal period to measure fasting heat production (FHP) for goats fed at maintenance levels should be between 40 h and 60 h of fasting. Consequently, the daily FHP, after 60 h of fasting, of Saanen and Anglo Nubian goats was 183.3 ± 16.3 and 211.1 ± 11.5 kJ/kg BW day respectively. The results presented herein are relevant for future studies of energy metabolism in goats.

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Section: Resultsmentioning

confidence: 99%

Fasting heat production of Saanen and Anglo Nubian goats measured using open‐circuit facemask respirometry

Fernandes

Lima

Almeida

et al. 2016

Animal Physiology Nutrition

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“…Both methods are partially dependent on each other and the close agreement between them may be considered as further evidence of the system's reliability (as shown by the regression analysis). Detailed descriptions of the errors on the estimation of RE (or HP) by the CN method have been given elsewhere (Blaxter 1967; Christensen et al 1988). Discrepancies between both methods averaged 0·055 when expressed as percentage of the MEI, a rather satisfactory value taking into account the considerable amount of technical and analytical work involved.…”

Section: Discussionmentioning

confidence: 99%

Low-cost mobile open-circuit hood system for measuring gas exchange in small ruminants: from manual to automatic recording

2015

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“…Among these factors, there is a positive relationship between intake and HP (Blaxter, 1967) because oxygen consumption is closely related to intake, and metabolic rates of body tissues decline as energy intake declines. HP for 1.0, 1.5 and 2.0 × NE m intakes was 479, 597 and 714 kJ/day kg 0.75 (s.e.m.…”

Section: Hpmentioning

confidence: 99%

“…Fasting metabolism in cattle is normally measured on day 3 or 4 of starvation, when the respiratory quotient (RQ) has fallen to~0.7 (Blaxter, 1967). However, results are varied in relation to the length (days) of fasting, as average daily RQ values decrease with longer periods of fasting (Blaxter and Wainman, 1966).…”

Section: Introductionmentioning

confidence: 99%

Effect of intake on fasting heat production, respiratory quotient and plasma metabolites measured using the washed rumen technique

Kim

McLeod

Koontz

et al. 2015

Animal

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The objective was to investigate the effect of intake before fasting on concentrations of metabolites and hormones, respiratory quotient (RQ) and fasting heat production (HP) using the washed rumen technique and to compare these values with those from the fed state. Six Holstein steers (360 ± 22 kg) were maintained at 21°C and fed three different energy intakes within a replicated 3 × 3 Latin square design with 21-day periods. Steers were fed alfalfa cubes to provide 1.0, 1.5 and 2.0 × NE m during 19 days of each experimental period. Steers were placed in individual metabolism stalls fitted with indirect calorimetry head-boxes on day 20 of each experimental period (FED steers) and fed their normal meal. On day 21 of each period the reticulorumen was emptied, washed and refilled with ruminal buffer (NaCl = 96; NaHCO 3 = 24; KHCO 3 = 30; K 2 HPO 4 = 2; CaCl 2 = 1.5; MgCl 2 = 1.5 mmol/kg of buffer) aerated with 75% N 2 and 25% CO 2 before introduction to the rumen (steers were not fed; WASHED steers). Each gas exchange was measured over 24 h. HP for 1.0, 1.5 and 2.0 × NE m were 479, 597 and 714 kJ/day kg 0.75 (s.e.m. = 16), respectively. The plateau RQ was 0.756, 0.824 and 0.860 for the 1.0, 1.5 and 2.0 × NE m intakes for the FED steers, respectively. After rumen washing, fasting HP was 331, 359 and 400 kJ/day kg 0.75 (s.e.m. = 13) for 1.0, 1.5, and 2.0 × NE m intakes before fasting, respectively. The RQ for WASHED rumen steers was 0.717, 0.710 and 0.719, respectively. Cortisol and β-hydroxybutyrate concentrations in WASHED rumen steers did not exceed threshold levels for severe energy deficit and stress as can be induced from prolonged fasting. This study demonstrates that a fasting state can be emulated using the washed rumen technique, minimizing the time required as opposed to traditional fasting methodologies, without causing a severe energy deficit and stress.

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Techniques in energy metabolism studies and their limitations

Cited by 36 publications

References 17 publications

Fasting heat production of Saanen and Anglo Nubian goats measured using open‐circuit facemask respirometry

Fasting heat production of Saanen and Anglo Nubian goats measured using open‐circuit facemask respirometry

Low-cost mobile open-circuit hood system for measuring gas exchange in small ruminants: from manual to automatic recording

Effect of intake on fasting heat production, respiratory quotient and plasma metabolites measured using the washed rumen technique

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