MEASUREMENT OF BIOAVAILABLE ENERGY IN POULTRY FEEDINGSTUFFS: A REVIEW

1982 ◽  
Vol 62 (4) ◽  
pp. 983-1048 ◽  
Author(s):  
I. R. SIBBALD

The importance of knowing the bioavailable energy (BE) content of poultry feedingstuffs is discussed in terms of economics, feed intake and the environment. The partition of ingested dietary energy is described and the effects of nutrient intake and of the microflora of the alimentary canal are outlined. Indirect biological, physical and chemical assays for BE are described and appraised. Procedures common to several direct bioassays for BE are discussed and points to consider in choosing between total excreta collection and the use of an indicator are presented. Assays for digestible energy, apparent metabolizable energy, true metabolizable energy and net energy are described. Variables affecting estimates of BE such as bird type, assay environment, assay diet and intake, assay design, the nitrogen correction, and metabolic plus endogenous losses are considered and a bioassay is recommended. The review concludes with brief speculation about future developments in the field of feedingstuff evaluation. Key words: Review, Energy, Assays, Methodology, Bioavailable

1977 ◽  
Vol 57 (2) ◽  
pp. 365-374 ◽  
Author(s):  
I. R. SIBBALD ◽  
K. PRICE

Thirty samples of wheat and 28 samples of oats were assayed for true and apparent metabolizable energy (TME, AME). Within grains, the difference TME−AME increased with decreasing AME values; there is evidence that this trend is associated with reduced voluntary consumption of AME assay diets containing low energy grains. The TME and AME data were compared with ME values predicted from physical and chemical data describing the grains. Previously published prediction equations were tested and new equations were derived. Comparisons between predicted and observed data suggested that both the TME and AME values of wheat were predicted with insufficient accuracy and precision for practical use. Similar comparisons using the oat data showed high correlations between observed and predicted values, although the predictions were no more accurate than for wheat; however, when data describing four samples of naked oats were removed, the correlations were reduced substantially. Comparisons involving data for the hulled oats indicated that most equations were able to predict AME better than TME. Multiple regression analysis was used to identify those combinations of variables best able to predict TME data. No combination of variables was best for both wheat and oats. The combinations of variables used in published equations performed quite well. With four variables, the percentage of the TME variation explained was as high as 52 for wheat, 82 for oats and 64 for hulled oats. Predictions based on air-dry data are associated with higher correlations than those based on dry matter data, but the air-dry predictions are the less useful in practice. The reason for this is discussed.


2019 ◽  
Vol 99 (4) ◽  
pp. 848-857 ◽  
Author(s):  
Sara Robinson ◽  
Elijah G. Kiarie

Production and metabolic consequences of feeding 49-wk-old Shaver white hens a high-energy low-crude-protein (HELP) diet were investigated over 6 wk. The test diets included standard diet [2750 kcal kg−1apparent metabolizable energy (AME) and 17.5% crude protein (CP)], HELP (3000 kcal kg−1of AME and 13.0% CP) diet, and HELP top dressed with selenium (HELP + Se). All diets had 0.3 mg Se kg−1as part of premix. Hens (33) were procured, three birds necropsied for baseline liver samples, and the rest placed in individual cages and allocated diets (n = 10). Feed intake (FI), hen day egg production (HDEP), and egg weight (EW) were monitored weekly. Plasma and liver samples were collected from all birds. Birds fed standard and HELP diets had similar (P > 0.05) FI (with exception of weeks 4 and 5) and HDEP, whereas HELP + Se depressed (P < 0.05) feed and nutrient intake at weeks 5 and 6, HDEP, and EW. There were no (P > 0.05) diet effects on hepatic weight and crude fat content. Birds fed HELP diets had lower (P > 0.05) concentration of plasma total protein, macrominerals, and some enzymes. Overall, HELP diet had minimal impact on production and metabolism; however, addition of Se had negative effects on hen performance.


1961 ◽  
Vol 57 (3) ◽  
pp. 419-425 ◽  
Author(s):  
K. L. Blaxter ◽  
F. W. Wainman

1. The utilization of the energy of the same ration by sheep and by cattle was measured using three steers and three sheep in twenty-one and twentyfour experiments, respectively. Five different amounts of the ration were given to each steer and six different amounts to each sheep.2. No differences of any magnitude were found in the percentage losses of dietary energy in faeces, in urine or as methane if comparisons were made at comparable nutritional levels. Faecal energy losses increased and urine energy losses and methane production fell with increase in feeding level, the feeding level being defined as the ratio of food intake to that required to attain an energy retention of zero.3. The net availability of metabolizable energy for maintenance was the same in both species at 80·4%. The net availability of energy for the production of fat was 53·5 ± 1·4 in sheep and 51·4 ± 2·6 in cattle.4. The results are discussed in relation to the effect of the amount of food given on the utilization of its energy. It is pointed out that net energy per unit of food declines with increasing intake, due firstly to a decline in digestibility and secondly to the fact that oxidative processes operative at and below maintenance are more efficient processes than is the synthesis of fat.


2019 ◽  
Vol 97 (7) ◽  
pp. 3056-3070 ◽  
Author(s):  
Emily A Petzel ◽  
Evan C Titgemeyer ◽  
Alexander J Smart ◽  
Kristin E Hales ◽  
Andrew P Foote ◽  
...  

AbstractTwo experiments were conducted to measure rates of ruminal disappearance, and energy and nutrient availability and N balance among cows fed corn husks, leaves, or stalks. Ruminal disappearance was estimated after incubation of polyester bags containing husks, leaves or stalks in 2 separate ruminally cannulated cows in a completely randomized design. Organic matter (OM) that initially disappeared was greatest for stalks and least for husks and leaves (P < 0.01), but amounts of NDF that initially disappeared was greatest for husks, intermediate for stalks, and least for leaves (P < 0.01). Amounts of DM and OM that slowly disappeared were greatest in husks, intermediate in leaves, and least in stalks (P < 0.01). However, amounts of NDF that slowly disappeared were greatest in leaves, intermediate in husks, and least in stalks (P < 0.01). Rate of DM and OM disappearance was greater for leaves, intermediate for husks and least for stalks, but rate of NDF disappearance was greatest for stalks, intermediate for leaves, and least for husks (P < 0.01). Energy and nutrient availability in husks, leaves, or stalks were measured by feeding ruminally cannulated cows husk-, leaf-, or stalk-based diets in a replicated Latin square. Digestible energy lost as methane was less (P = 0.02) when cows were fed leaves in comparison to husks or stalks, and metabolizable energy (Mcal/kg DM) was greater (P = 0.03) when cows were fed husks and leaves compared with stalks. Heat production (Mcal/d) was not different (P = 0.74) between husks, leaves, or stalks; however, amounts of heat produced as a proportion of digestible energy intake were less (P = 0.05) among cows fed leaves in comparison to stalks or husks. Subsequently, there was a tendency (P = 0.06) for net energy available for maintenance from leaves (1.42 Mcal/kg DM) to be greater than stalks (0.91 Mcal/kg DM), and husks (1.30 Mcal/kg DM) were intermediate. Nitrogen balance was greater when cows were fed leaves, intermediate for husks, and least for stalks (P = 0.01). Total tract digestion of NDF was greater (P < 0.01) for husks and leaves compared with stalks. Husks had greater (P = 0.04) OM digestibility in comparison to stalks, and leaves were intermediate. Apparently, greater production of methane from husks in comparison to leaves limited amounts of energy available for maintenance from husks even though total-tract nutrient digestion was greatest when cows were fed husks or leaves.


2021 ◽  
pp. 101288
Author(s):  
M.M. Khalil ◽  
M.R. Abdollahi ◽  
F. Zaefarian ◽  
P.V. Chrystal ◽  
V. Ravindran

1958 ◽  
Vol 195 (3) ◽  
pp. 654-658 ◽  
Author(s):  
F. W. Hill ◽  
L. B. Carew ◽  
A. van Tienhoven

Increased fat production in diethylstilbestrol-treated chicks was found to be due primarily to increased energy consumption and to a lesser extent to preferential synthesis of fat at the expense of protein tissue. This was shown in experiments comparing normal and estrogen-treated male chicks with respect to gains in live weight, fat and protein at two planes of nutrition, and the yield of metabolizable and productive (net) energy which they obtained from the diet. It was found that the fattening effect could not be due to increased digestibility, increased net energy yield from absorbed nutrients, or lowered heat production. Under the influence of estrogen, total tissue gain expressed in Calories was increased, and was composed of greater fat gain and lower protein gain. Tissue energy gains were a linear function of metabolizable energy consumption. This relationship predicted equal tissue energy gains under pair-feeding conditions, which was confirmed experimentally.


2016 ◽  
Vol 54 (2) ◽  
pp. 214-226
Author(s):  
O. A. CASTELÁN-ORTEGA ◽  
C. G. MARTÍNEZ-GARCÍA ◽  
F. L. MOULD ◽  
P. DORWARD ◽  
G. C. MIRANDA-DE LA LAMA ◽  
...  

SUMMARYThe objectives were to assess the following: (1) the relationship between sward height and chemical composition of four pasture types in association with grazing behaviour and body condition score (BCS) of dairy cows, and (2) the possibility of developing predictive equations of the nutrient intake and grazing behaviour within a continued grazing system. Pasture type had a significant (p < 0.01) effect on nutrient supply from January to June for all pastures investigated. Ryegrass–white clover pasture (RW) had the highest metabolizable protein and metabolizable energy, followed by kikuyu pasture (KP), which was significantly (p < 0.001) higher than native pastures 1 and 2 (NP1 and NP2). The highest values for effective grazing time, bite rate and BCS were found when dairy cows grazed RW followed by KP, NP2 and NP1. The results suggested that pasture type and sward height influenced grazing behaviour and BCS of dairy cows during the dry season. In the same vein, RW showed higher effective grazing time, bite rate, nutrient intake and BCS than the other three pastures suggesting that RW pastures that appear to be more expensive than native pastures could result in superior cow performance.


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