The efficiency of conversion of ingested food to unit of body substance (ECI, also termed "growth efficiency") is an index measure of food fuel efficiency in animals. The ECI is a rough scale of how much of the food
ingested is converted into growth in the animal's
mass
Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physi ...
. It can be used to compare the growth efficiency as measured by the weight gain of different animals from consuming a given quantity of food relative to its size.
The ECI effectively represents efficiencies of both
digestion
Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into th ...
(approximate digestibility or AD) and
metabolic efficiency, or how well digested food is converted to mass (efficiency of conversion of digested food or ECD). The formula for the efficiency of food fuel is thus:
:
These concepts are also very closely related to the
feed conversion ratio (FCR) and feed efficiency.
References
Food science
Metabolism
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