Are there differences in the chemical form of trace minerals on bioavailability?
Traditionally, supplemental trace minerals have been supplied to livestock in the form of inorganic salts: sulfates, oxides and chlorides, such as copper sulfate or copper chloride. The use of organic trace minerals has increased due to reports of improved feed efficiency, growth, reproduction and immune response. One study showed that the bio-availability of zinc proteinate was 159% of the bio-availability of zinc sulfate in rats, while another study showed that zinc methionine had 300-400% the potency of zinc sulfate in young channel catfish. Work by Jerry Spears from North Carolina reviewed the effects of feeding zinc methionine to cattle and reported improved performance, carcass quality and immune response. The following table, developed by Wayne Greene from Texas A&M, compares the bio-availability of several trace elements from different sources. Relative bioavailability of trace minerals from different sources (adapted from W.
