Simulation of energy metabolism in the simple-stomached animal

1978 ◽  
Vol 39 (2) ◽  
pp. 235-254 ◽  
Author(s):  
A. R. Schulz
Keyword(s):  
Energy Metabolism ◽  
Adenosine Triphosphate ◽  
Metabolic Pathways ◽  
Close Agreement ◽  
Energy Requirement ◽  
Maintenance Energy ◽  
Quasi Steady State ◽  
Computer Programme ◽  
Energy Retention ◽  
Maintenance Energy Requirement

1. A computer programme is described which simulates energy metabolism in the whole animal. Simulation was based on representation of the animal as a quasi-steady-state system.2. Input for the programme consisted of the chemical composition of the diet and an estimate of either the maintenance energy requirement or an estimate of energy retention.3. Simulation was performed by estimating the yield of adenosine triphosphate in the major metabolic pathways operative in simple-stomached animals, and on the utilization of adenosine triphosphate in major anabolic processes.x4. Results obtained from simulation were in close agreement with experimental observations reported by McCracken (1975).

Net utilization of roughage and concentrate diets by sheep

1976 ◽  
Vol 35 (2) ◽  
pp. 201-209 ◽  
Author(s):  
P. I. Wilke ◽  
F. J. Van Der Merwe
Keyword(s):  
South African ◽  
Energy Requirement ◽  
Experimental Period ◽  
Energy Gain ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Maintenance Energy ◽  
Energy Retention ◽  
Maintenance Energy Requirement ◽  
Body Energy

1. Two diets, an all-roughage diet and a high-concentrate diet, were fed at two levels, a low level of estimated 1.5 times maintenance energy requirement and a higher level of estimated two times maintenance energy requirement, to South African Mutton Merino castrated male sheep, aged 13 months and in fairly lean condition at the start of the 93 d experimental period..2. Body composition and energy retention were determined using the comparative slaughter technique and two series of digestibility and balance studies were done during the course of the experiment. Metabolizability of each diet was estimated and corrected for fermentation heat using the fermentation balance approach..3. Although there were significantly different rates of energy gain on different diets and feeding levels, fat energy gained (% total energy gained) was similar for the four groups, i.e. 78–80..4. Regression of energy gain v. corrected metabolizable energy (ME) intake indicated that the maintenance energy requirements of sheep used in this experiment were 310.2 and 302.3 kJ ME/kg body-weight0.75 per d and the values for net utilization of ME for body energy gain were 0.411 and 0.479 with the roughage and concentrate diets respectively..5. It was concluded that the estimated maintenance energy requirements of sheep obtained in this study are realistic values and that the efficiency of utilization of surplus ME for the two diets did not differ significantly.

Estimation of the Maintenance Energy Requirements of Beef Cattle and Lambs

1997 ◽  
Vol 1997 ◽  
pp. 118-118
Author(s):  
R.W.J. Steen ◽  
L.E.R. Dawson ◽  
N. Lavery ◽  
D.E. Kirkpatrick ◽  
S.D. Johnston
Keyword(s):  
Beef Cattle ◽  
Energy Requirement ◽  
Energy Requirements ◽  
Maintenance Energy ◽  
High Fibre ◽  
Energy Retention ◽  
Metabolisable Energy ◽  
Maintenance Energy Requirement ◽  
Using Data ◽  
Gut Metabolism

The maintenance energy requirement of an animal can be defined as the daily metabolisable energy (ME) intake at which it is in zero energy balance. Maintenance energy requirements can be estimated either by measuring fasting metabolism or from a regression relationship between ME intake and energy retention for a number of animals given a range of ME intakes. However maintenance energy requirements may vary according to the composition of the diet, as higher intakes of high-fibre diets have promoted greater rates of gut metabolism than lower intakes of low-fibre diets. In the present study maintenance energy requirements of beef cattle and lambs have been estimated by regressions between ME intake and energy retention using data from a series of studies involving diets based on grass silage or fresh grass and concentrates.

scholarly journals Maintenance energy requirements and forage intake of purebred vs. crossbred beef cows1

2020 ◽  
Vol 4 (2) ◽  
pp. 1182-1195
Author(s):  
Claire E Andresen ◽  
Aksel W Wiseman ◽  
Adam McGee ◽  
Carla Goad ◽  
Andrew P Foote ◽  
...  
Keyword(s):  
Energy Requirement ◽  
Growth Efficiency ◽  
Energy Requirements ◽  
Maintenance Energy ◽  
Calf Growth ◽  
Crossbred Cows ◽  
Breed Type ◽  
Main Effect ◽  
Forage Intake ◽  
Maintenance Energy Requirement

Abstract The objective of this study was to investigate the impacts of cow breed type and age on maintenance requirements, feed energy utilization, and voluntary forage intake. The main effect of breed type included Angus (ANG; n = 32) and Hereford × Angus (HA; n = 27) lactating cows. The main effect of age included 2- and 3-yr-old (YOUNG; n = 29) and 4- to 8-yr-old (MATURE; n = 30) cows. Within breed type and age class, cows were randomly assigned to 1 of 2 pens for a total of 8 pens, each housing 7 to 9 cow/calf pairs. To determine maintenance energy requirements, cows and calves were limit-fed for 105 d to body weight (BW) and body condition score (BCS) stasis. There were no differences between breeds in cow hip height, BW, average milk yield (P > 0.31), diet digestibility, or cow maintenance energy requirement (P = 0.54). Crossbred cows had greater BCS (P < 0.05) throughout the experiment. Efficiency of calf growth was not different between breeds when expressed as feed intake of the cow/calf pair nor as energy intake of the pair per unit of calf BW gain (P ≥ 0.31). Young cows produced less milk per day and per unit of BW0.75 (P < 0.01); however, there was no effect of cow age on maintenance energy requirement, diet digestibility, or efficiency of calf growth (P > 0.10). Subsequently, a 45-d experiment was conducted to determine voluntary low-quality forage intake. Cows were housed in dry-lot pens equipped with shade, windbreaks, and feed bunks with free-choice access to clean water and a chopped hay ration was provided ad libitum to determine forage intake. Daily forage intake was lower (P = 0.05) for HA compared with ANG (123 vs. 132 g/kg BW0.75, respectively) although there was no difference in BW. However, HA cows sustained greater BCS (P < 0.01). There was no difference (P = 0.60) in forage intake per unit of BW0.75 due to cow age. Results indicate similar calf growth efficiency among breed types although crossbred cows maintained greater body energy stores and consumed less low-quality forage during the voluntary intake experiment. These differences could not be attributed to lower maintenance energy requirements. Neither maintenance energy requirement nor calf growth efficiency was different between young and mature cows.

scholarly journals Faecal endogenous loss of calcium in young sheep

1989 ◽  
Vol 61 (1) ◽  
pp. 59-65 ◽  
Author(s):  
J. S. Chrisp ◽  
A. R. Sykes ◽  
N. D. Grace
Keyword(s):  
White Clover ◽  
Dry Matter ◽  
Research Council ◽  
Agricultural Research ◽  
Energy Requirement ◽  
Energy Requirements ◽  
Maintenance Energy ◽  
Agricultural Research Council ◽  
The Mean ◽  
Maintenance Energy Requirement

1. Two groups of eight 6–7-month-old wether lambs were offered either a frozen ryegrass (Lolium perenne L.)-white clover (Trifolium repens L.) pasture or a ryegrass-white clover hay, containing 12.1 and 6.4 g calcium/ kg dry matter (DM) respectively. Within groups the amounts offered to individual sheep ranged from 0.5 to 2.0 times the estimated maintenance energy requirements.2. A single intravenous injection of 150 μCi 45Ca as CaCl2. 2H2O, and stable balances were used to determine absorption, faecal endogenous loss and balance of Ca.3. Faecal endogenous loss of Ca increased by 1.2 mg/kg body-weight (W) per d with each g/kg W per d increase in DM intake regardless of the diet. At any DM intake the mean faecal endogenous loss was 5.5 mg/kg W per d higher in the sheep offered the frozen herbage diet when compared with those on the hay diet. At any Ca intake the mean faecal endogenous loss was 6.9 mg/kg W higher in sheep offered the hay diet compared with those on the frozen herbage.4. At feeding levels of about 1.5–2 times the estimated maintenance energy requirement the observed faecal endogenous loss of Ca ranged from 35 to 50 mg/kg W per d, which is two- to threefold greater than the present estimate of the Agricultural Research Council (1980) of 16 mg/kg W per d.5. A simple model to explain the variation in faecal endogenous loss of Ca between the present study with young sheep and that with lactating ewes (Chrisp et al. 1989) also offered herbage diets is developed, which incorporates the concept of a true endogenous loss related to DM intake and a net endogenous loss reflecting the extent of re-absorption of Ca endogenous losses within the gastrointestinal tract.

scholarly journals Differences in Taurine Synthesis Rate among Dogs Relate to Differences in Their Maintenance Energy Requirement

2007 ◽  
Vol 137 (5) ◽  
pp. 1171-1175 ◽  
Author(s):  
Kwang S. Ko ◽  
Robert C. Backus ◽  
John R. Berg ◽  
Michael W. Lame ◽  
Quinton R. Rogers
Keyword(s):  
Energy Requirement ◽  
Synthesis Rate ◽  
Maintenance Energy ◽  
Maintenance Energy Requirement

Field peas as a feed for growing and finishing pigs. 2. Effects of substituting peas for meat meal or fish meal in conventional diets

1984 ◽  
Vol 24 (127) ◽  
pp. 507 ◽  
Author(s):  
RL Davies
Keyword(s):  
Pisum Sativum ◽  
Fish Meal ◽  
Energy Requirement ◽  
Growing Pigs ◽  
Maintenance Energy ◽  
Finishing Pigs ◽  
Finishing Diets ◽  
Meat Meal ◽  
Field Peas ◽  
Maintenance Energy Requirement

In three experiments the effects of substituting field peas (Pisum sativum) for meat meal and/or fish meal in diets fed to growing and finishing pigs were studied. The inclusion of up to 28% peas in growing and finishing diets did not affect the digestible energy intake of pigs fed at up to 3.5 times their maintenance energy requirement. When peas comprised 53% of a diet fed to growing pigs, intake was depressed by 8%. With the exception of this diet, responses were consistent with changes in dietary lysine. It is concluded that, at up to about 40% of the diet, the lysine and energy value of field peas to growing and finishing pigs is consistent with analysed levels of these nutrients.

A Study on the Determination of the Maintenance Energy Requirement in Growing Goats

2020 ◽  
Vol 40 (2) ◽  
pp. 111-116
Author(s):  
Sang Uk Chung ◽  
◽  
Qi-Man Zhang ◽  
Se Young Jang ◽  
Yeong Sik Yun ◽  
...  
Keyword(s):  
Energy Requirement ◽  
Maintenance Energy ◽  
Maintenance Energy Requirement ◽  
Growing Goats

scholarly journals Pichia pastoris Exhibits High Viability and a Low Maintenance Energy Requirement at Near-Zero Specific Growth Rates

2016 ◽  
Vol 82 (15) ◽  
pp. 4570-4583 ◽  
Author(s):  
Corinna Rebnegger ◽  
Tim Vos ◽  
Alexandra B. Graf ◽  
Minoska Valli ◽  
Jack T. Pronk ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Growth Rates ◽  
Specific Growth ◽  
Energy Requirement ◽  
Maintenance Energy ◽  
Content Type ◽  
Chemostat Cultures ◽  
Zero Growth ◽  
Maintenance Energy Requirement ◽  
Specific Growth Rates

ABSTRACTThe yeastPichia pastorisis a widely used host for recombinant protein production. Understanding its physiology at extremely low growth rates is a first step in the direction of decoupling product formation from cellular growth and therefore of biotechnological relevance. Retentostat cultivation is an excellent tool for studying microbes at extremely low specific growth rates but has so far not been implemented forP. pastoris. Retentostat feeding regimes were based on the maintenance energy requirement (mS) and maximum biomass yield on glucose (YX/Smax) estimated from steady-state glucose-limited chemostat cultures. Aerobic retentostat cultivation enabled reproducible, smooth transitions from a specific growth rate (μ) of 0.025 h−1to near-zero specific growth rates (μ < 0.001 h−1). At these near-zero specific growth rates, viability remained at least 97%. The value ofmSat near-zero growth rates was 3.1 ± 0.1 mg glucose per g biomass and h, which was 3-fold lower than themSestimated from faster-growing chemostat cultures. This difference indicated thatP. pastorisreduces its maintenance energy requirement at extremely low μ, a phenomenon not previously observed in eukaryotes. Intracellular levels of glycogen and trehalose increased, while μ progressively declined during retentostat cultivation. Transcriptional reprogramming toward zero growth included the upregulation of many transcription factors as well as stress-related genes and the downregulation of cell cycle genes. This study underlines the relevance of comparative analysis of maintenance energy metabolism, which has an important impact on large-scale industrial processes.IMPORTANCEThe yeastPichia pastorisnaturally lives on trees and can utilize different carbon sources, among them glucose, glycerol, and methanol. In biotechnology, it is widely used for the production of recombinant proteins. For both the understanding of life in its natural habitat and optimized production processes, a better understanding of cell physiology at an extremely low growth rate would be of extraordinary value. Therefore, we have grownP. pastorisin a retentostat, which allows the cultivation of metabolically active cells even at zero growth. Here we reached doubling times as long as 38 days and found thatP. pastorisdecreases its maintenance energy demand 3-fold during very slow growth, which enables it to survive with a much lower substrate supply than baker's yeast.

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