There are currently a significant number of chemical, structural, and bioavailable
differences among the various sources of organic microelements used in bird rations.
The most common organic sources of Mn, Zn, Fe, Cu can be the compounds with
specific amino acids, amino acid complexes, protein, polysaccharides and organic
acids.
One of the most popular commercial sources of organic Manganese is Mn-
proteinate. However, Wang et al. [11], assessing the biological availability of Mn-
proteinate and Mn-sulfate in chicken broilers, based on several linear regressions
between Mn concentration, superoxide dismutase activity (MnSOD) and mRNA
(MnSOD) level in the gray tissue, did not reveal any significant differences (P>0.21)
in bioavailability between these sources. Lu L. et al. [7] were investigating the
influence of various sources of Manganese on slaughter indices, meat quality, lipid
oxidation, activity of individual enzymes in internal fat and meat, and the level of
mRNA (MnSOD) in broiler chicken meat. The birds that received the source of
Manganese in the form of Mn AA A or Mn AA B had a lower (P<0.05) activity of
lipoprotein lipase in internal fat, lower content of malondialdehyde (P<0.03) in pelvic
limb muscles, the higher activity of MnSOD (P<0.02) and the level of mRNA MnSOD
in the thoracic muscles and muscles of the pelvic limbs than those receiving MnSO
4
x
H
2
O. Thus, the results of this experiment confirm that organic Manganese is more
affordable than inorganic.
In studies on laying hens, when adding Mn-proteinate to the ration, the scientists
received better indices of the weight of birds, the weight of eggs and their strength, the
strength of the large tibia versus the use of Mn-sulfate [12]. According to the authors,
these positive changes are associated with the redistribution of mineral elements in the
body of hens and with a certain accumulation of Manganese in the bone tissue, which
the use of organic forms of Mn contributed to.
The results of most experiments performed in recent years have demonstrated a
high relative biological availability of organic Zn sources, even if this has not always
been reflected in improving the productivity. Brooks et al. indicate a high relative
bioavailability of Zn in the body of chicken broilers with the use of Zinc propionate.
When comparing Zinc propionate with sulfate by the body weight of chickens, the Zn
concentration in the large ankle and, in fact, the whole bone tissue, the better biological
availability, which made 116-119 %, was established.
Some positive changes in growth rates and immunological characteristics have
been observed when feeding the elevated levels of Zinc (90-120 mg/kg) in the form of
glycinate, but no probable difference was observed in these indices between the groups
that consumed 120 mg/kg of Zinc of either organic or inorganic origin [9].
Interesting results were obtained by Attia et al. [5] when feeding different sources
of Zinc (oxide and Bio-Plex®) young ducks. Scientists have found somewhat negative
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