Abstract:
The concentration of trace elements in the liver is used as an indicator of the mineral nutritional status of an animal, as a benchmark
of environmental mineral exposure, to follow the metabolism of an element in the body and for various other purposes.
Concentrations are expressed on a wet (fresh) liver basis or on a dry liver basis. From a literature search and evidence from an
analytical laboratory, large variations (varying from < 20% to > 40%) have been recorded on the percentage of moisture in the
livers of ruminants. Such variations potentially compromise the interpretation of results on mineral concentrations in livers, and
preclude robust comparisons between studies. Among the factors that can affect the moisture content of livers are: inconsistencies
in sampling and preparation of liver samples; exposure to toxic substances; ill-health of the animal; fat content of the liver; and age
of the animal. It was estimated that the mean dry matter (DM) content of the livers of healthy ungulates containing less than 1%
liver fat is between 27.5% and 28.5%, and on a fat-free basis 25–26% DM. For routine analyses of liver samples it is suggested that
to limit variations owing to differences in liver moisture content, liver mineral concentrations should be expressed on a DM basis,
and for in-depth scientific studies on mineral metabolism on a dry, fat-free basis. However, if mineral concentrations are expressed
on a wet basis, it is advisable to supply the liver DM content as well.
