Energy metabolisable

Wilkinson (1984) presents information showing that the amount of metabolisable energy utilised on dairy farms can vary by more than a factor of four. He suggests that high levels of efficiency can be achieved by ... 

Fodder crops are useful in organic rotations they are high yielding crops with high levels of metabolisable energy. They will also serve as a cleaning crop for weeds. 

Changes in dietary metabolisable energy supply do not seem to affect the expression of immunity to GIN (Donaldson et al., 1997 Houdijk et al.,... 

Im, H.L., Ravindran, V., Ravindran, G., Pittolo, P.H. and Bryden, W.L. (1999) The apparent metabolisable energy and amino acid digestibility of wheat, triticale and wheat middlings for broiler chickens as affected by exogenous xylanase supplementation. Journal of the Science of Food and Agriculture 79,1727-1732. 

Ravindran, V., Tilman, Z.V., Morel, P.C.H., Ravindran, G. and Coles, G.D. (2007) Influence of (3-glucanase supplementation on the metabolisable energy and ileal nutrient digestibility of normal starch and waxy barleys for broiler chickens. Animal Feed Science and Technology 134,45-55. 

Roberts, S- 0., Coward, W Schlingenseipen, K., Nohiia, V, and Lucas, A. (1986). Comparison of the doubly labeled water ( H2 0) method with indirect calorimetry and a nutrient balance study for simultaneous determination of energy expenditure, water intake, and metabolisable energy intake in preterm infants. Am.. Clin. Natr. 44,315-322. 

Figure 4. Energy production in the form of biofuels (straw and biogas), metabolisable energy in crops and fossil energy use for crop production ...

Metabolisable energy in crop production Fossil energy use for crop production... 

Metabolisable energy (ME) content is predicted using DE content and certain characteristics concerning the composition of the feedstuff linked to energy losses in the form of gas and urine. The transformation equations are specific for each type of animal. In the case of poultry, ME is measured directly since energy losses in faeces and urine cannot easily be separated. 

In conclusion.TMEn is the best estimation of the metabolisable energy of a diet because it is independent of the level of ingestion and does not into account the endogenous fraction that does not come directly from the diet Theoretically, only TMEn values are additive However, when ingestion levels are close to spontaneous ingestion levels in the birds, AMEn and TMEn are similar. 

Figure 6. Protocol for the measurement of metabolisable energy used by INRA.

Carre and Rozo, 1990 Fisher and McNab, 1987) taking into account the average chemical composition given in the tables. They are metabolisable energy values at zero nitrogen balance. 

Bourdillon A., Carre B., Conan L, Duperray J., Huyghebaert G., Leclercq B., Lessire M., McNab J. M.,Wiseman J., 1990. European reference method for the in vivo determination of metabolisable energy v ith adult cockerels reproducibility, effect of food intake and comparison with individual laboratory methods. Brit Poult Se/ 31,557-565. 

Fisher C., McNab J., 1987. Techniques for determining the metabolisable energy (ME) content of poultry feed. 

Metabolisable energy (ME) can be predicted from digestible energy using regression equations between the ME/DE ratio and the chemical composition of the feed materials. These equations were established by INRA, using a data file of 79 results. 

There are few data on the digestibility of amino acids in fish. In general, the digestibility of crude protein reflects quite accurately that of amino acids. Due to the fact that the measurement of metabolisable energy is difficult and also of little benefit in fish nutrition (Cho and Kaushik, 1990), we have chosen to use digestible energy data. 

Apparent metabolisable energy corrected for zero nitrogen balance, in MJ/kg... 

Factors affecting the metabolisable energy values of foods... 

Table 11.1 Metabolisable energy values of some typical foods (MJ/kg DM)...

Fig. 11.3 The difference method for estimating the heat increment of foods. A is the basal metabolism and B and C represent heat production at metabolisable energy intakes of 40 MJ and 100 MJ, respectively. For the sake of simplicity, the relationship between heat production and metabolisable energy intake is shown here as being linear, i.e. ABC is a straight line however, as explained later in the chapter, this is not usually the case.

In indirect calorimetry, using respiratory exchange, heat production is estimated, and energy retention is calculated as the difference between metabolisable energy intake and heat production (as in Table 11.2). An alternative approach is to estimate energy retention more directly and to calculate heat production by difference. 

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