DEPOSITION OF ORGANIC TRACE METAL COMPLEXES AS FEED ADDITIVES IN FARM ANIMALS

Abstract

Trace elements are essentials for maintenance and production of farm animals, but most of the feedingstuffs do not contain adequate amount of most of them, therefore supplementation of complete feeds with trace elements is necessary. However, the rate of absorption and tissue deposition of trace elements from different complexes is also different which may have food safety aspects because of the maximum level of some trace minerals. The present review, based on scientifically proved data, discuss about the rate of absorption and deposition of different metal (Cu, Zn, Fe and Mn) proteinates, amino acid chelates (e.g lysine, methionine, methyl-hydroxy-methionine) and humic acid complexes of trace elements. The results showed that metal proteinates have higher rate of tissue accumulation as compared to inorganic salts, and additionally some metal-proteinates (e.g. copper-proteinate) also improves the tissue deposition of manganese. Metal propionates, as possible new trace element supplements have positive effects on the rate of absorption which was proved by the higher blood serum levels. In the case of humic acid chelates there are some data about their positive effect on bioavailability of trace minerals but those were not scientifically proven. In conclusion it can be stated that organic metal complexes have better bioavailability than their inorganic counterparts, in particular modern farm animal genotypes with higher requirement level and also in stress conditions.