digestibility

Digestibility describes the amount of energy or nutrients absorbed with a food that is not excreted in the faeces . The digestibility is usually given in percent (max. 100) or as a factor (max. 1.0).

Determination of digestibility

Determining the digestibility of food can be done in several ways:

" In vivo " methods are studies on living things and are most often used in duodenal living things, which include apparent and true digestibility .
In situ , i.e. through investigations “directly on site”, e.g. B. directly in the rumen of ruminants through so-called fistulation and " in sacco " methods (see nylon bags)
In vitro , for example through simulation or laboratory analysis

Types of digestibility

Apparent and true digestibility

A distinction is made between apparent and true digestibility. The apparent digestibility is determined by comparing the substance supplied with the substance removed ( faeces ) . The relative deviation represents the degree of digestibility. ${\ displaystyle {\ text {sV}}}$ ${\ displaystyle A}$ ${\ displaystyle F}$

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However, this is actually only an "apparent" digestibility, since parts produced by the intestinal flora are also added during the digestive tract . Only when these proportions are factored out do you get what is known as true digestibility ( ). ${\ displaystyle e}$ ${\ displaystyle {\ text {wV}}}$

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Faecal and ileal digestibility

Decisive for the degree of digestibility is at which point in the digestion the faeces are measured. One speaks of faecal digestibility when the differences are measured over the entire intestine (ie from the mouth to the anus). Whereas, the ileal digestibility of only the difference to the terminal ileum measures. The faecal measurement can overestimate the digestibility compared to the ileal measurement, since the catabolic processes predominate in the large intestine , which means that a large part of the substances absorbed there is broken down again or otherwise excreted (e.g. as urine ).

Individual evidence

↑ ^a ^b ^c ^d Helmut Meyer, Josef Kamphues, Britta Dorbencker, Michael Fröhlich: Supplements for animal nutrition: For study and practice . 12th edition. Hannover, Germany, ISBN 978-3-7944-0241-0 , pp. 13 ff .
↑ Wesseling, Bernhard .: On the effectiveness of feed amino acids in pigs . 1st edition Cuvillier, Göttingen 2004, ISBN 3-86537-002-0 , p. 7th ff .

[:0-1] Helmut Meyer, Josef Kamphues, Britta Dorbencker, Michael Fröhlich: Supplements for animal nutrition: For study and practice . 12th edition. Hannover, Germany, ISBN 978-3-7944-0241-0 , pp. 13 ff .

[2] Wesseling, Bernhard .: On the effectiveness of feed amino acids in pigs . 1st edition Cuvillier, Göttingen 2004, ISBN 3-86537-002-0 , p. 7th ff .