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Zinc / Zinc sources
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Functions
The element zinc is essential for plants, animals, and humans.
It activates several enzymes and is a component of many important
metallo-enzymes. Zinc is the most abundant intracellular trace
mineral in animals and total body zinc approaches that of iron.
The element is critically involved in cell replication and in
the development of cartilage and bone. Signs of zinc deficiency
in animals and humans include retarded growth, abnormal skeletal
formation, delayed sexual development, alopecia, dermatitis,
abnormal feathering, and impaired reproduction in both males
and females. Fetal abnormalities occur and hatchability of eggs
is reduced.
Many animal diets require supplementation with zinc because
of either low dietary levels or the presence of dietary factors
that decrease bio-availability of the mineral (e.g. phytic acid).
Zinc is primarily absorbed from the small intestine.
Zinc is supplemented in diets for all species of livestock in
the range of 30 to 250 ppm to cover their requirements. The
supplementation rate of zinc for poultry is mostly lowest, while
this is highest for pigs. Zinc is mostly supplemented as zinc
oxide or zinc sulphate in animal diets.
- Quality
parameters
BIOLOGICAL AVAILABILITY
Both zinc oxide and zinc sulphate ensure an excellent bio-availability
of the supplied zinc source.
The
high bio-availability of both zinc compounds is well documented
in the literature and an overview is presented in the EMFEMA
Bioavailability Guide. The findings can be summarized as follows:
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The
zinc bio-availabilities for zinc oxide and zinc sulphate
show no meaningful differences in pigs and ruminants |
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In
poultry however, some studies showed an equal availability
for zinc oxide, while other studies showed a reduced availability
compared to zinc sulphate. The scientific committee concluded
that the relative zinc bio-availability for zinc oxide
compared to zinc sulphate in poultry depended heavily
on the processing method, origin, texture and Zn content
of the zinc oxide. |
UNDESIRABLE ELEMENTS
The zinc oxide and zinc sulphate offered to the market by the
Emfema member producers comply with directive 2002/32/EC of
7 may 2002 on undesirable substances in animal feed.
- Analytical
methods
| zinc |
EDTA tritration |
| lead |
atomic
absorption spectrometry |
| cadmium |
atomic
absorption spectrometry |
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