All mineral elements present in poultry feed at elevated level
can produce several adverse health problems to poultry. Therefore,
the essential as well as heavy metals must be restricted in the diet
at the adequate levels in order to achieve best response and to offer
protection for the poultry as well as consumers. For the safety of
both, dietary maximum tolerable levels of these elements have
been provided which is serving as guidelines to control the quality
of poultry feeds. National research council (NRC) has published the
maximum tolerable levels (MTL) as well as required concentrations
of certain dietary minerals for poultry (NRC, 1980, 1994).
As there are many possible dietary sources of toxic elements for
poultry, but satisfactory quality control measures at the poultry
feed industries tied with good manufacturing practices and knowledgeable
nutritionists can significantly decrease the probability of
considerable contamination.