scholarly journals Application of the law of diminishing returns to describing the relationship between metabolizable energy intake and growth rate in broilers

2001 ◽  
Vol 10 (4) ◽  
pp. 661-670 ◽  
Author(s):  
H. Darmani Kuhi ◽  
E. Kebreab ◽  
E. Owen ◽  
J. France
Keyword(s):  
Growth Rate ◽  
Energy Intake ◽  
Metabolizable Energy ◽  
Diminishing Returns ◽  
The Law ◽  
Metabolizable Energy Intake ◽  
The Relationship

A comparative evaluation of functions for the analysis of growth in male broilers

2003 ◽  
Vol 140 (4) ◽  
pp. 451-459 ◽  
Author(s):  
H. DARMANI KUHI ◽  
E. KEBREAB ◽  
S. LOPEZ ◽  
J. FRANCE
Keyword(s):  
Body Weight ◽  
Fixed Point ◽  
Energy Intake ◽  
Body Weight Gain ◽  
Energy Requirement ◽  
Metabolizable Energy ◽  
Wide Range ◽  
Diminishing Returns ◽  
Metabolizable Energy Intake ◽  
The Relationship

Data from six studies with male broilers fed diets covering a wide range of energy and protein were used in the current two analyses. In the first analysis, five models, specifically re-parameterized for analysing energy balance data, were evaluated for their ability to determine metabolizable energy intake at maintenance and efficiency of utilization of metabolizable energy intake for producing gain. In addition to the straight line, two types of functional form were used. They were forms describing (i) diminishing returns behaviour (monomolecular and rectangular hyperbola) and (ii) sigmoidal behaviour with a fixed point of inflection (Gompertz and logistic). These models determined metabolizable energy requirement for maintenance to be in the range 437–573 kJ/kg of body weight/day depending on the model. The values determined for average net energy requirement for body weight gain varied from 7·9 to 11·2 kJ/g of body weight. These values show good agreement with previous studies. In the second analysis, three types of function were assessed as candidates for describing the relationship between body weight and cumulative metabolizable energy intake. The functions used were: (a) monomolecular (diminishing returns behaviour), (b) Gompertz (smooth sigmoidal behaviour with a fixed point of inflection) and (c) Lopez, France and Richards (diminishing returns and sigmoidal behaviour with a variable point of inflection). The results of this analysis demonstrated that equations capable of mimicking the law of diminishing returns describe accurately the relationship between body weight and cumulative metabolizable energy intake in broilers.

A note on the effects of body fatness and level of food intake on the rate of fat loss in lactating ewes

1982 ◽  
Vol 34 (3) ◽  
pp. 355-357 ◽  
Author(s):  
R. T. Cowan ◽  
J. J. Robinson ◽  
I. McDonald
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Body Fat ◽  
Metabolizable Energy ◽  
Body Fatness ◽  
Fat Loss ◽  
Body Fat Content ◽  
Metabolizable Energy Intake ◽  
Image Position ◽  
The Relationship

ABSTRACTData from three comparative slaughter experiments involving a total of 73 ewes were used to study the influence of body fat content at the start of lactation (X1 kg) and of metabolizable energy intake (X2, MJ/day), on the rate of loss of body fat by lactating ewes over the first 6 weeks of lactation (Y, g/day). The relationship was described by the equation:Thus the rate of fat loss was greater for ewes with higher initial fat contents, but the differential became less as metabolizable energy intake increased. Since increases in body fatness depress food intake it was not possible to prevent loss of body fat during early lactation in fat ewes given high concentrate diets ad libitum. The likely response in milk yield to increase in body fatness at parturition is therefore strongly dependent on the relative levels of body fatness and metabolizable energy intake. The value of any improvement in condition of the ewe at parturition may be considerable when metabolizable energy intake during lactation is low but much less when it is expected to be high.

scholarly journals Estimation of the total efficiency of metabolizable energy utilization for maintenance and growth by cattle in tropical conditions

2005 ◽  
Vol 34 (3) ◽  
pp. 1006-1016 ◽  
Author(s):  
Douglas Sampaio Henrique ◽  
Ricardo Augusto Mendonça Vieira ◽  
Pedro Antônio Muniz Malafaia ◽  
Maurício Cordeiro Mancini ◽  
André Luigi Gonçalves
Keyword(s):  
Energy Intake ◽  
Heat Production ◽  
Metabolizable Energy ◽  
Energy Utilization ◽  
Total Efficiency ◽  
Net Energy ◽  
Tropical Conditions ◽  
Metabolizable Energy Intake ◽  
The Relationship ◽  
Direct Measures

Data of 320 animals were obtained from eight comparative slaughter studies performed under tropical conditions and used to estimate the total efficiency of utilization of the metabolizable energy intake (MEI), which varied from 77 to 419 kcal kg-0.75d-1. The provided data also contained direct measures of the recovered energy (RE), which allowed calculating the heat production (HE) by difference. The RE was regressed on MEI and deviations from linearity were evaluated by using the F-test. The respective estimates of the fasting heat production and the intercept and the slope that composes the relationship between RE and MEI were 73 kcal kg-0.75d-1, 42 kcal kg-0.75d-1 and 0.37. Hence, the total efficiency was estimated by dividing the net energy for maintenance and growth by the metabolizable energy intake. The estimated total efficiency of the ME utilization and analogous estimates based on the beef cattle NRC model were employed in an additional study to evaluate their predictive powers in terms of the mean square deviations for both temperate and tropical conditions. The two approaches presented similar predictive powers but the proposed one had a 22% lower mean squared deviation even with its more simplified structure.

scholarly journals Growth Rate and Energetics of Arabian Babbler (Turdoides squamiceps) Nestlings

The Auk ◽  
2001 ◽  
Vol 118 (2) ◽  
pp. 519-524 ◽  
Author(s):  
Avner Anava ◽  
Michael Kam ◽  
Amiram Shkolnik ◽  
A. Allan Degen
Keyword(s):  
Growth Rate ◽  
Energy Intake ◽  
Body Mass ◽  
Energy Content ◽  
Metabolizable Energy ◽  
Logistic Growth ◽  
Growth Rate Constant ◽  
Adult Body Mass ◽  
Group Members ◽  
Metabolizable Energy Intake

Abstract Arabian Babblers (Turdoides squamiceps) are territorial, cooperative breeding passerines that inhabit extreme deserts and live in groups all year round. All members of the group feed nestlings in a single nest, and all group members provision at similar rates. Nestlings are altricial and fledge at about 12 to 14 days, which is short for a passerine of its body mass. Because parents and helpers feed nestlings, we hypothesized that the growth rate of nestlings is fast and that they fledge at a body mass similar to other passerine fledglings. Using a logistic growth curve, the growth rate constant (k) of nestlings was 0.450, which was 18% higher than that predicted for a passerine of its body mass. Asymptotic body mass of fledglings was 46 g, which was only 63% of adult body mass, a low percentage compared to other passerines. Energy intake retained as energy accumulated in tissue decreased with age in babbler nestlings and amounted to 0.29 of the total metabolizable energy intake over the nestling period. However, energy content per gram of body mass increased with age and averaged 4.48 kJ/g body mass. We concluded that our hypothesis was partially confirmed. Growth rate of babbler nestlings was relatively fast compared to other passerine species, but fledgling mass was relatively low.

scholarly journals 223 Evaluation of dietary characteristics and empty body chemical components affecting the relationship between heat production and metabolizable energy intake in growing beef cattle

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 158-159
Author(s):  
Phillip A Lancaster
Keyword(s):  
Chemical Composition ◽  
Energy Intake ◽  
Body Fat ◽  
Heat Production ◽  
Metabolizable Energy ◽  
Energy Concentration ◽  
Chemical Components ◽  
Data Set ◽  
Metabolizable Energy Intake ◽  
The Relationship

Abstract Metabolizable energy required for maintenance varies with diet and empty body chemical composition. The objective was to quantify the relationships of dietary characteristics and empty body chemical composition with heat production. A literature search was performed to compile data (31 studies, 214 treatment means) on metabolizable energy intake (MEI) and composition of empty body gain in growing steers and heifers. Data analysis were performed using R statistical package for mixed models with study as random variable. Nonlinear regression of energy gain (EG) on MEI indicated the relationship was not curvilinear in this data set, likely due to lack of negative values of EG. Further analyses were conducted using a linear model. Dietary characteristics of roughage level (0–100% of diet DM) and CP (10–25% diet DM), metabolizable energy concentration (1.3–3.3 Mcal/kg DM), and roughage type were evaluated in the model. Roughage sources were categorized into no roughage, silage, hay, pellets, silage + pellets, and hay + pellets. Of the empty body chemical components, proportion of fat in the empty body (EBFp) and in the gain (EBFgp) had a significant (P < 0.001) interaction with MEI on HP. Of the dietary characteristics, roughage level and type had a significant (P < 0.001) interaction with MEI on HP; however, when both were included in the model, roughage type was not significant (P > 0.10). The final model was 47.01 ± 12.54 + 0.630 ± 0.05*MEI – 132.3 ± 64.7*EBFp + 0.0007 ± 0.0001*MEI*Roughage level + 0.753 ± 0.24*MEI*EBFp – 0.268 ± 0.032*MEI*EBFgp with an R2 of 0.919 and an AIC of 1614 compared with 0.867 and 1695 for the simple linear regression model of HP on MEI. In conclusion, greater empty body fat decreased the intercept, and greater empty body fat proportion and levels of roughage in the diet increased the slope between HP and MEI, whereas greater percentage of fat in the empty body gain decreased the slope between HP and MEI.

Metabolizable energy intake of client-owned adult cats

2015 ◽  
Vol 99 (6) ◽  
pp. 1025-1030 ◽  
Author(s):  
M. Thes ◽  
N. Koeber ◽  
J. Fritz ◽  
F. Wendel ◽  
B. Dobenecker ◽  
...  
Keyword(s):  
Energy Intake ◽  
Metabolizable Energy ◽  
Metabolizable Energy Intake ◽  
Adult Cats

Effect of air temperature and energy intake on body mass, body composition and energy requirements in sheep

2002 ◽  
Vol 138 (2) ◽  
pp. 221-226 ◽  
Author(s):  
A. ALLAN DEGEN ◽  
B. A. YOUNG
Keyword(s):  
Energy Intake ◽  
Body Mass ◽  
Air Temperature ◽  
Total Body Water ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Water Volume ◽  
Air Temperatures ◽  
Metabolizable Energy Intake ◽  
Total Body

Body mass was measured and body composition and energy requirements were estimated in sheep at four air temperatures (0 °C to 30 °C) and at four levels of energy offered (4715 to 11785 kJ/day) at a time when the sheep reached a constant body mass. Final body mass was affected mainly by metabolizable energy intake and, to a lesser extent, by air temperature, whereas maintenance requirements were affected mainly by air temperature. Mean energy requirements were similar and lowest at 20 °C and 30 °C (407·5 and 410·5 kJ/kg0·75, respectively) and increased with a decrease in air temperature (528·8 kJ/kg0·75 at 10 °C and 713·3 kJ/kg0·75 at 0 °C). Absolute total body water volume was related positively to metabolizable energy intake and to air temperature. Absolute fat, protein and ash contents were all affected positively by metabolizable energy intake and tended to be related positively to air temperature. In proportion to body mass, total body water volume decreased with an increase in metabolizable energy intake and with an increase in air temperature. Proportionate fat content increased with an increase in metabolizable energy intake and tended to increase with an increase in air temperature. In contrast, proportionate protein content decreased with an increase in metabolizable energy intake and tended to decrease with an increase in air temperature. In all cases, the multiple linear regression using both air temperature and metabolizable energy intake improved the fit over the simple linear regressions of either air temperature or metabolizable energy intake and lowered the standard error of the estimate. The fit was further improved and the standard error of the estimate was further lowered using a polynomial model with both independent variables to fit the data, since there was little change in the measurements between 20 °C and 30 °C, as both air temperatures were most likely within the thermal neutral zone of the sheep. It was concluded that total body energy content, total body water volume, fat and protein content of sheep of the same body mass differed or tended to differ when kept at different air temperatures.

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