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

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.

1996 ◽  
Vol 63 (2) ◽  
pp. 289-296 ◽  
Author(s):  
N. Quiniou ◽  
J. Noblet ◽  
J.-Y. Dourmad

AbstractThe effect of energy supply on physical composition of body weight gain between 45 and 100 kg was studied in Large White castrated males (cLW), crossbred Pietrain × Large White castrated males (cPPX) and boars (bPPX). The pigs were either given food ad libitum and kept in individual pens in experiment 1, or allocated to four energy levels (0·70, 0·80, 0·90, and 1·00 ad libitum) and kept in metabolism cages in experiment 2. Daily protein supplies were calculated to be the same at the four energy levels within each type of pig and non-limiting for growth. Five additional animals for each type of pig were slaughtered at 45 kg. Daily tissue gain was measured according to the comparative slaughter technique. The daily lean gain increased with metabolizable energy (ME) intake according to a linear-plateau relationship whereas the daily fat gain increased linearly. The type of pig significantly affected the slope of the relationship between lean gain and ME intake (from 15 to 22 g per extra MJ ME) but not the slope of the relationship between fat gain and ME intake (10 g per extra MJ ME on average). Increased energy intake was associated with increased fatness of body-weight gain, which was higher in cLW and cPP× than in bPP×.


Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3893 ◽  
Author(s):  
Desiree M. Sigala ◽  
Adrianne M. Widaman ◽  
Bettina Hieronimus ◽  
Marinelle V. Nunez ◽  
Vivien Lee ◽  
...  

Sugar-sweetened beverage (sugar-SB) consumption is associated with body weight gain. We investigated whether the changes of (Δ) circulating leptin contribute to weight gain and ad libitum food intake in young adults consuming sugar-SB for two weeks. In a parallel, double-blinded, intervention study, participants (n = 131; BMI 18–35 kg/m2; 18–40 years) consumed three beverages/day containing aspartame or 25% energy requirement as glucose, fructose, high fructose corn syrup (HFCS) or sucrose (n = 23–28/group). Body weight, ad libitum food intake and 24-h leptin area under the curve (AUC) were assessed at Week 0 and at the end of Week 2. The Δbody weight was not different among groups (p = 0.092), but the increases in subjects consuming HFCS- (p = 0.0008) and glucose-SB (p = 0.018) were significant compared with Week 0. Subjects consuming sucrose- (+14%, p < 0.0015), fructose- (+9%, p = 0.015) and HFCS-SB (+8%, p = 0.017) increased energy intake during the ad libitum food intake trial compared with subjects consuming aspartame-SB (−4%, p = 0.0037, effect of SB). Fructose-SB decreased (−14 ng/mL × 24 h, p = 0.0006) and sucrose-SB increased (+25 ng/mL × 24 h, p = 0.025 vs. Week 0; p = 0.0008 vs. fructose-SB) 24-h leptin AUC. The Δad libitum food intake and Δbody weight were not influenced by circulating leptin in young adults consuming sugar-SB for 2 weeks. Studies are needed to determine the mechanisms mediating increased energy intake in subjects consuming sugar-SB.


1982 ◽  
Vol 34 (3) ◽  
pp. 355-357 ◽  
Author(s):  
R. T. Cowan ◽  
J. J. Robinson ◽  
I. McDonald

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.


1990 ◽  
Vol 64 (3) ◽  
pp. 625-637 ◽  
Author(s):  
M. G. Macleod

Heat production (HP) and the intake and retention of energy and nitrogen were measured at 20° in growing female broiler fowl given diets with metabolizable energy (ME) contents ranging from 8 to 15 MJ/kg at each of two crude protein (nitrogen × 6.25; CP) contents (130 and 210 g/kg). ME intake was partially controlled by the birds, but increased by 30% over the range of dietary ME concentration. CP intake varied directly with dietary CP:ME ratio, indicating that control of energy intake took priority and that food intake did not increase in order to enhance amino acid intake on low-CP diets. Maintenance energy requirement and fasting HP were not affected by diet. Although the HP of fed birds was significantly affected by dietary energy source, there was no evidence for regulatory diet-induced thermogenesis as energy intake increased. Total energy retention doubled on the higher-energy diets as a result of increased intake and retention efficiency in the absence of any compensation by diet-induced thermogenesis. The proportion of energy retained as fat was negatively correlated with dietary CP:ME ratio. It was concluded that the growing female broiler fowl responded to large differences in energy intake and dietary CP concentration not by changes in rate of energy dissipation as heat but by changes in the quantity of energy retained and in the partition of retained energy between body protein and body fat.


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

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.


1969 ◽  
Vol 20 (2) ◽  
pp. 375 ◽  
Author(s):  
Graham N McC

Energy, carbon, and nitrogen balances were determined in adult wether sheep given a diet of lucerne hay and whole oats at several planes of nutrition between fasting and ad libitum. Four sheep were studied when their weight was c. 30 kg (10% fat) and later when they weighed c. 75 kg (33% fat); another four were studied at c. 70 kg (30% fat) and later at c. 45 kg (16% fat). The most obvious effect of fatness was loss of appetite. Voluntary food intake began to decline when body weight approached 60 kg and was half of the maximal amount when the sheep weighed 70 kg or more; one very fat sheep ate only 100–200 g food/day for several weeks. 1n addition, environmental changes such as transfer from a pen to a cage or respiration chamber often caused temporary inappetence when the sheep were in fat condition but seldom when they were lean. Fasting metabolic rate increased with body weight in accordance with the relationship generally applicable to adult sheep except when the sheep were in the anorectic phase of obesity, at which time their metabolic rate was 30–40% above normal. The digestibility of the diet was not dependent on the fatness of the sheep, nor was the relationship between metabolizable and digestible energy. At each level of feeding, the heaviest sheep produced most heat, but differences were less than at fasting; oxidation of fat, rather than protein, was responsible. When daily heat production and metabolizable energy were both expressed as multiples of the fasting energy loss, all sheep conformed to one relationship; the same held for the relation between energy balance and metabolizable energy. Net efficiency (change of energy balance divided by change of metabolizable energy intake) was 78% for maintenance and 55% for production, irrespective of body condition. Gross efficiency (energy storage divided by gross energy intake) was strongly influenced by body condition. When fed ad libitum, thin sheep achieved an efficiency of c. 26 % and fat sheep reached 21 % whereas anorectic very fat sheep never exceeded 10%. Thin, fat, and very fat sheep required 400, 500 and 650 g dry matter/day respectively for maintenance (zero gross efficiency).


1996 ◽  
Vol 63 (2) ◽  
pp. 277-288 ◽  
Author(s):  
N. Quiniou ◽  
J.-Y. Dourmad ◽  
J. Noblet

AbstractBetween 45 and 100 kg body weight, Large White castrated males (cLW), and crossbred Pietrain × Large White castrated males fcPP×) and boars (bPP×) were either given food ad libitum in experiment 1 or allocated to four energy levels (0·70, 0·80, 0·90, 1·00 ad libitum) in experiment 2. Daily protein and amino acid supplies were calculated to be non-limiting for growth. Protein (PD) and lipid (LD) deposition rates were measured according to the comparative slaughter technique over the whole experimental period (experiments 1 and 2) and according to the nitrogen and energy balance technique at four stages of growth: 48, 64, 79 and 94 kg mean body weight (experiment 2). Average daily gain increased linearly with metabolizable energy (ME) intake, the slope of the relationship being significantly different between types of pig (from −28 to +36 g per additional MJ ME). Daily PD increased with ME intake above maintenance (MEp) according to a linear-plateau relationship in the three types of pig: the slope was significantly affected by type of pig (from +3·4 to 6·0 g per extra MJ MEp) but not by stage of growth. Daily LD increased linearly with MEp intake; neither the type of pig nor the stage of growth affected its slope (+13-5 g per extra MJ MEp). The LD/PD ratio in the extra body-weight gain associated with increased energy intake was affected only by the type of pig.


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