A comparison of methods for estimating the metabolisable energy of a sample of grass meal

Jönsson, G.; McNab, J. M.

doi:10.1080/00071668308416749

Cited by 19 publications

(7 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Much of the subsequent debate, which has taken place concerning the effectiveness of these rapid methods, has tended to revolve around which is the better system to use, AME or TME (Farrell, 1981;Sibbald, 1981). However, it has been our contention that, because AME and TME are mathematically related to each other (Jonsson and McNab, 1983), assays should be judged on how well food intake and endogenous energy losses (EEL) can be measured and that whether AME or TME values are derived from the data is largely irrelevant (McNab and Fisher, 1982). The assay devised (Sibbald, 1976) and subsequently modified (Sibbald, 1979;Sibbald and Morse, 1983) to derive TME values suggests a means of measuring food intake very precisely and a simple way of determining EEL.…”

Section: Introductionmentioning

confidence: 99%

Modified assay for true and apparent metabolisable energy based on tube feeding

McNab

Blair

1988

British Poultry Science

Self Cite

128

View full text Add to dashboard Cite

1. To improve the accuracy with which true metabolisable energy (TME) values of feedingstuffs are determined, a modification to the assay based on tube-feeding is proposed. 2. To ensure that the gastrointestinal tracts of the experimental birds are as empty as possible at the start of the assay it is recommended that the normal food is withdrawn 48 h before tube-feeding. 3. In order to partly alleviate the effects of starvation, all birds are given two doses of 25 g glucose (as an aqueous solution) about 40 and 16 h before tube-feeding. Birds, from which endogenous energy losses are to be derived, are fed 50 g glucose rather than given no food. 4. All birds are given 50 ml water by tube about 32 h after feeding to overcome any effects induced by low water intake. 5. A comparison of the two procedures with 8 feedingstuffs showed that the mean coefficient of variation was reduced from 5.5% to 1.5% for TME and from 4.7% to 1.8% for TME.

show abstract

Section: Introductionmentioning

confidence: 99%

Modified assay for true and apparent metabolisable energy based on tube feeding

McNab

Blair

1988

British Poultry Science

Self Cite

128

View full text Add to dashboard Cite

show abstract

“…In bioassays where chicks are fed ad libitum, RN is usually positive and AME> AME n (Sibbald and Slinger, 1963). When reference and substituted diets are fed, IE and RN often differ among treatment groups (Jonsson and McNab, 1983), and this contributes to variation in AME and AME n values. In assays with adult cockerels fed ad libitum, RN tends to vary about zero, causing AME and AME n values to be similar.…”

Section: Discussionmentioning

confidence: 99%

Relationships Between Apparent and True Metabolizable Energy and the Effects of a Nitrogen Correction

Wolynetz

Sibbald

1984

Poultry Science

View full text Add to dashboard Cite

Some relationships among four common estimates of bioavailable energy (BE), namely apparent (AME) and true (TME) metabolizable energy and their nitrogen-corrected equivalents (AME n , TME n ) are discussed. Data from four poultry experiments are used to illustrate the relationships.In terms of accuracy, both AME and AME n substantially underestimate BE at low feed intakes. Within the range of practical ad libitum feed intakes, AMEAME n when RN>0. At low intakes, TME overestimates BE but the difference is less than the underestimation of BE either AME or AME n . The bioassay for TME n provides a good estimate of BE at all levels of intake.The precision of the BE estimators tends to increase with feed intake and is usually greater when a nitrogen correction is applied. The variance associated with the excreta energy of fasted control birds causes the TME and TME n estimates to be less precise than the corresponding AME and AME n values at a specific level of feed intake.Theoretical considerations and experimental evidence indicate that TME n is the most useful estimate of BE for practical purposes.(Key words: apparent metabolizable energy, true metabolizable energy, nitrogen correction, bioavailable energy interrelationships)

show abstract

“…A notable feature of these results is the consistent AME and AME n values using the DSQ, conventional and Farrell methods, irrespective of diet or food consumption (see also Longe and Tona, 1988). Criticism has been levelled at Downloaded by [] at 00:03 05 February 2015 the Farrell method (Sibbald, 1985) because several workers have been unable to obtain satisfactory food intakes; consequently AME values were depressed (Jonsson and McNab, 1983;Schang and Hamilton, 1982). Had these workers trained their roosters to consume their daily maintenance food allowance according to recommendations in the original procedure and pelleted the experimental diets (Farrell, 1977(Farrell, , 1978a, such difficulties would probably not have arisen.…”

Section: Apparent Metabolisable Energy Corrected To Nitrogen Balance mentioning

confidence: 96%

The estimation of endogenous excreta and the measurement of metabolisable energy in poultry feedstuffs using four feeding systems, four assay methods and four diets

Farrell

Thomson

Preez

et al. 1991

British Poultry Science

View full text Add to dashboard Cite

1. Four different methods (dual semi-quick (DSQ), conventional, a true metabolisable energy (ATM) method and Farrell's rapid method) were used to measure in adult roosters the apparent metabolisable energy (AME) and true metabolisable energy (TME) of four maize-based diets with bran inclusions of 0, 200, 400 and 600 g/kg 2. Daily food intakes per bird were 75 g (or ad libitum) (H), 35 g (M) and 10 g (L). AME values determined by DSQ, conventional and Farrell methods were not different at the two highest intakes but were depressed at L intakes. ATM method often gave different values from other methods, particularly at the lowest intake. 3. The linear relationships between food intake and excreta energy yielded intercept values of 13 to 32 kJ/d for three methods; but ATM method yielded intercepts of 31 to 52 kJ/d. In a separate experiment it was demonstrated that a linear model may not be the most appropriate fit to such data. Removal of data for the 10 g/d intake yielded linear regression equations with intercepts not significantly different from zero for the two continuous feeding methods (i.e. a zero estimate for endogenous urinary and metabolic faecal energy (EEL), but for the two methods using a single input after fasting, intercepts were almost always positive. This confirms Härtel's (1986) observation of the absence of EEL under continuous feeding but its ever presence using a TME assay. 4. Correction of AME for EEL to obtain TME tended to increase values for all diets and also within a diet with decreasing intakes. The effect of correcting AME to nitrogen balance (n) was to give AME n values that were more consistent between diets and reduced differences between methods. For the conventional method differences between the three intakes on all diets were greatly reduced. 483 Downloaded by [] at 00:03 05 February 2015 484 D. J. FARRELL ETAL.5. There is reason to be concerned about the many different metabolisable energy values obtained using the ATM method compared to the three other methods and the basis for correcting for endogenous excreta. It is concluded that because of the uncertainty of EEL values, their variation and application, the AME system should be retained.

show abstract

A comparison of methods for estimating the metabolisable energy of a sample of grass meal

Cited by 19 publications

References 12 publications

Modified assay for true and apparent metabolisable energy based on tube feeding

Modified assay for true and apparent metabolisable energy based on tube feeding

Relationships Between Apparent and True Metabolizable Energy and the Effects of a Nitrogen Correction

The estimation of endogenous excreta and the measurement of metabolisable energy in poultry feedstuffs using four feeding systems, four assay methods and four diets

Contact Info

Product

Resources

About