6.1.2.4. Indirect calorimetry: calculation of energy turnover

Measurement of O2 consumption (VO2) allows calculation of honey bee energy turnover (P, metabolic power) by multiplication with the caloric equivalent (oxyjoule equivalent, CE). This is called indirect calorimetry.

          P (W) = VO2 × CE   (l O2 s-1 × J l O2-1  =  J s-1  =  W)                   (Equation 2)

 The caloric equivalent depends on the substrate combusted in an animal's metabolism. In honey bees this is mainly carbohydrates (Rothe and Nachtigall, 1989). Table 2 summarizes some values of the caloric equivalent and of the calorific value of biological substrates.

Table 2. Caloric equivalents (oxyjoule equivalents) and calorific values of biological substrates.

Substrate

Caloric equivalent (kJ l O2-1)

Calorific value (kJ g-1)

Carbohydrates
general mean
sucrose
glucose


~21.15
21.117
21.0


~17.2
16.8
15.6

Lipids

~19,6

~38,9

Proteins

~19,65

~17,2

 

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