TECHNICAL
Comparing ORGANIC SELENIUM sources
Pierre-André Geraert
Mickaël Briens
Yves Mercier Y.G. Liu
There is a growing interest in using selenium (Se) based products as an antioxidant,
not only for breeding stock, but also for commercial animals. A wide range of products
is available. The question is how to choose the most efficient one? Chemical analysis
does not appear sufficient to appreciate the bioavailability of the large range of
dietary sources of selenium available for animal feeding. Tissue Se deposition is a
reliable criteria to evaluate the bio-efficacy of various Se sources write PIERRE-ANDRÉ
GERAERT, MICKAËL BRIENS, YVES MERCIER and Y.G. LIU*.
26
(H2Se) to synthesize de novo SeCys.
A rapid bioavailability test to
evaluate efficacy potential of
selenium sources
In normal conditions, the Se
content in the breast muscle of
day-old chicks depends on the Se
supply in breeder’s diets. If not
supplemented with Se or only with
sodium selenite, chicks show a
decrease of their muscle Se content
at day 7 compared to hatch. Based
on 7-d dietary supplementation of
young chicks, the authors developed
a rapid evaluation test on biological
value of different organic Se sources
using muscle Se concentration.
Seleno yeast: not all the
same yet very difficult in
differentiation
Numerous study reports have
demonstrated that Se-yeasts may
Figure 1: Selenomethionine content of various seleno-yeasts (SY) from different
producers and different batches of production.
Selisseo av. 99.5%
100
90
80
Se-Met in % Total Se
wide range of products is
available; from inorganic, sodium
selenite or selenate coated or
not, even nanoparticles to organic
forms such as selenized yeasts,
chelates of selenium methionine
(SeMet), pure forms of SeMet or
hydroxy-selenomethionine, and
some complexes sources of Se
based on mixing mineral Se with
glycinates, proteinates, etc. It has
been confirmed that, comparing
with mineral selenium, its organic
forms are better absorbed thus serve
selenium needs more efficiently.
Research has revealed that
selenium incorporated as
selenocysteine (SeCys) is the key
amino acid supporting the antioxidant properties of most of the
25 selenoproteins identified in
animal species or humans such as
glutathione peroxidase, thioredoxine
reductase and methionine sulfoxide
reductase. However, this SeCys has
to be synthetized de novo by the
cells and cannot be supplied through
feeds. Dietary SeCys undergoes
complete transformation to selenide
v
A
SY1 av. 38.9%
70
SY2 av. 62.8%
SY3 av. 58.1%
SY4 av. 63.2%
60
50
40
30
20
10
0
SY1 SY2 SY3 SY4 Selisseo
ASIAN POULTRY MAGAZINE – August 2015
Figure 2: Comparative muscle Se deposition at 7 days of age in broilers fed Se at
chelate
Figure
Comparative
muscle
Se(0.2
deposition
at Se).
7 days of age in broilers fed Se atSelenomethionine
the same dietary
the
same2:dietary
incorporation
level
ppm total
incorporation level (0.2 ppm total Se).
As for chelates of minerals (Zn, Cu,
100
96
100
Mn) which show better bioavailability
of several minerals, producers have
tried to develop so-called chelates of
80
selenium. However, Se is a metalloid
and cannot be chelated. The only true
65
70
available chelate existing is a chelate
60
of selenomethionine with Zn, thus a
50
source of SeMet and Zn. However,
50
methionine or selenomethionine
40
are absorbed through the same
transporters and chelating methionine
30
23
20
19
or SeMet with Zn, indeed enhances
20
Zn absorption, but will reduce SeMet
absorption (Figure 2). Moreover,
10
chelation has often been promoted to
0
enhance stability of the molecule, it is
SS
GLY
PRO
SY1
SY2 CHEL
SM
SO
however clear that such weak bond
Naselenite
selenite
(SS),
Se-glycinate
Se-proteinate
(PRO), Seleno-yeasts
(SY1chelate
and SY2),
of improve the stability. Anyway,
cannot
Na
(SS),
Se-glycinate
(GLY),(GLY),
Se-proteinate
(PRO), Seleno-yeasts
(SY1 and SY2),
of chelate
selenomethionine
and
(CHEL),
selenomethionine
pure OH-SeMet
SO). Se deposition
selenomethionine
and
zinczinc
(CHEL),
pure pure
selenomethionine
(SM) or(SM)
pure or
OH-SeMet
(Selisseo,(Selisseo,
SO).
measuring the stability of such
from
Se-Yeasts
the SeMet
the yeasts
vs.(45
65%
SY1
Se
deposition
fromdepends
Se-Yeastson
depends
on thecontent
SeMet of
content
of the (45
yeasts
vs.for
65%
for and
SY1 SY2,
and respectively).
chelate in feed processing is almost
SY2, respectively).
conventional
A new Se-yeast source has recently appeared based on Torula yeast. Its specificityimpossible
lies on the through
fact
and this rapid in vivo test
that it does not contain mainly SeMet but seleno-homolanthionine (SeHLan). However,analyses
such a yeast
seemsvary
difficult
to analyse
a batch-to-batch
basis, as
laboratories do
not possess
a calibration
to analyse
onmost
a batch-to-batch
basis,
in their
SeMet on
contents
is the
only way to determine the
v largely
sample
for this
guarantee
willasthus
only
be based on
Se. Moreover, bioavailability
scientists
most
laboratories
dototal
not possess
from
supplier
toSeHLan.
supplier The
as well
as
of such a molecule.
compared
pure SeMet
and SeHLan on ratsaand
concluded
SeHLan
being
only 60% of SeMet efficiency.
calibration
sample
for this
SeHLan.
from
batch-to-batch
of production
More recent works compared Se-Torula yeast with other Se-yeasts, without measuringGlycinates
their SeMet and Proteinates of
The guarantee will thus only be based
(Figure 1). Indeed, to produce a
contents, suggesting similar efficacy between those yeasts. It further points out the importance
Se:
justofmixture of inorganic Se
totalcomparing
Se. Moreover,
scientists
Se-yeast,
process is based
onSe-yeastson
completethe
characterization
of the
when
efficacy.
and
organic materials
compared pure SeMet and SeHLan
growing a yeast on mineral Se
on rats and concluded SeHLan being
allowing
the yeasts tochelate
integrate part
Selenomethionine
Another type of selenium sources is
As Se
for into
chelates
of minerals
which
show
of severaloften
minerals,
60%
of better
SeMetbioavailability
efficiency. More
of this
SeMet.
Managing(Zn, Cu, Mn)only
mentioned as organic ones: the
producers have
tried to
so-called chelates
of selenium.
However,
Se is a metalloid
and cannot
be
recent works
compared
Se-Torula
fermentation
process
fordevelop
optimum
glycinates,
proteinates
or complexes.
chelated.
Thewhile
only true
available
is a other
chelate
of selenomethionine
with Zn, thus a source
yeast with
Se-yeasts,
without
yeast
growth,
feeding
the chelate existing
These sources are usually obtained
of SeMet and Zn. However, methionine or selenomethionine
areSe
absorbed
the for
same
transporters
Stability oftheir
organic
sources:through
important
optimal
efficiency
measuring
SeMet
contents,
yeasts
with mineral Se that is toxic, is
through
mixing
mineral Se (Na
and chelating methionine or SeMet with Zn, indeed
enhancesabove,
Zn absorption,
SeMet
As mentioned
measuringbut
thewill
totalreduce
Se content
in various Se sources is easy, but determ
suggesting
similar
efficacy
between
already
rather
tricky
and
often
gives
selenite)
and
amino
acids organic
or soyasolutions have b
absorption (Figure 2). Moreover, chelation has
often
been
promoted
to
enhance
stability
of
the
molecule,
chemical form is much more difficult. Since Se does not disappear, many
those
yeasts.
It further
points
rise
large variability
the process,
protein
hydrolysates.
As
for chelates,
it isto
however
clear thatinsuch
weak bond cannot
improve
stability.
Anyway, measuring
the
stability
of
tested
under the
various
feed
processing
conditions
or even
challenging
conditions
but only total Se co
out
themeasured.
importance
of an
complete
leading
to variations
the SeMetis almost impossible
were
approach
does not
reveal
the
of organic
such chelate
in feedin
processing
throughSuch
conventional
analyses
and
this
rapid
in dynamics
vivo is not
Se
being
atrue
metalloid
proneSe sources.
test is thewhich
only way
to only
determine
of such aofmolecule.
characterization
the Se-yeasts
contents,
is the
activethe bioavailability
to complexation. Using this rapid
Extrusion
as used
in aquafeed or petfood processing represents the harshest and most challen
when
comparing
efficacy.
part in the end product. Measuring
7-d broiler test, it has been possible
feed processing.
Under
the stability of hydroxy-SeMet (HMSeBA, Selisseo) has b
Glycinates
and Proteinates
of Se:
of inorganic
Se such
and conditions,
organic materials
the
total Se content
of the yeasts
is just mixture
determined
using
either
a
standard
0.2
ppm
concentration
Another type of selenium sources is often mentioned as organic ones: the glycinates, proteinatesororeven for analytical precision 2 ppm th
easy,
but determining SeMet content
measurement
of HMSeBA
andSe
not(Na
total
Se. In both
conditions,
HMSeBA displayed fully stable with
complexes. These sources are usually obtained
through
mixing
mineral
selenite)
and
aminoat
acids
Figure
3: Stability
of hydroxy-selenomethionine
included
0.2 or 2 ppm total
recovery
rates
higher
than
95%prone
(Figure
3).
isornot
often
performed
in routine
soya
protein
hydrolysates.
As for chelates,
Se
being
a
metalloid
is
not
to
complexation.
Using
Se to extrusion processing (115-130°C, 115 bars) - recoveries before or after
lab
often
at the
thisand
rapid
7-d not
broiler
test,user’s
it haslevel.
been possible to measure the benefits of such selenium sources on Se
extrusion.
Figure 3: Stability of hydroxy-selenomethionine included at 0.2 or 2 ppm total Se to extrusio
Depending
onthe
themuscular
deposition
of this
deposition in
tissue.
Figure 2 clearly shows no additional value of those so-called organic
processing (115-130°C, 115 bars) - recoveries before or after extrusion.
Se sources
over more
mineral
Se. to get
SeMet,
it is even
difficult
1.9
2
a precise measurement.
1.8
Figure 2 clearly shows that the
1.8
efficiency of Se deposition in breast
1.6
muscle of 7-d chicks is largely
ADISSEO Asia Pacific Pte Ltd I 30 Hill Street #03-03 I Singapore 179360
1.4
Tel: +65
6543 of
1121 I Fax: +65 6545 3547 I www.adisseo.com I feedsolutions.adisseo.com
influenced by the SeMet
content
Company Registration No: 200108221W
1.2
the yeasts. The variation of SeMet
content of various Se-yeasts has
1
shown a range from 21 to 70%
0.8
depending on source or between
0.6
different batches of the same product.
0.4
A new Se-yeast source has recently
0.21
0.2
0.2
appeared based on Torula yeast.
Its specificity lies on the fact that it
0
does not contain mainly SeMet but
Before
After
Before
After
seleno-homolanthionine (SeHLan).
2 ppm
2 ppm
0.2 ppm
0.2 ppm
However, such a yeast seems difficult
80
HMSeBA (mg/kg)
Muscle Se (mg/kg)
TECHNICAL
90
28
However, not all pure Se molecules exhibit the same behaviour. Pure L-SeMet appeared to be
ASIAN POULTRY
MAGAZINE
August 2015
unstable when mixed with a standard premix containing
trace minerals
and–vitamins
and even mor
unstable when adding choline chloride.
Stability of organic Se sources:
important for optimal efficiency
As mentioned above, measuring
the total Se content in various Se
sources is easy, but determining
its chemical form is much more
difficult. Since Se does not disappear,
many organic solutions have been
tested under various feed processing
conditions or even challenging
conditions but only total Se contents
were measured. Such an approach
does not reveal the true dynamics of
organic Se sources.
Extrusion as used in aquafeed or
petfood processing represents the
harshest and most challenging feed
processing. Under such conditions,
the stability of hydroxy-SeMet
(HMSeBA, Selisseo) has been
determined using either a standard
0.2 ppm concentration or even for
analytical precision 2 ppm through
measurement of HMSeBA and not
total Se. In both conditions, HMSeBA
displayed fully stable with recovery
rates higher than 95% (Figure 3).
However, not all pure Se molecules
exhibit the same behaviour. Pure
L-SeMet appeared to be unstable
when mixed with a standard premix
containing trace minerals and
vitamins and even more unstable
when adding choline chloride.
Figure 4 shows that under
challenging conditions such as 40°C,
75% relative humidity for a month,
up to 85 % of the SeMet was no
Figure 4: Stability of pure SeMet or hydroxy-SeMet under challenging conditions
(open bags, 40°C, 75% RH, 1 month) as measured by SeMet or HMSeBA
Figure
4: Stability of pure SeMet or hydroxy-SeMet under challenging conditions (ope
recoveries.
75% RH, 1 month) as measured by SeMet or HMSeBA recoveries.
100
90
80
% Recovery
to measure the benefits of such
selenium sources on Se deposition in
the muscular tissue. Figure 2 clearly
shows no additional value of those
so-called organic Se sources over
mineral Se.
70
-75% -83%
60
50
40
30
20
10
0
100
83
73.7
Selisseo
Pure
Premix
100
25
16.6
SeMet
Premix + choline
Conclusion
longer detected from the sample
is definitely to enhance tissue Se
Although there are a large variety of selenium sources on the market, most of suppliers o
compared
to
less
than
20%
with
notform.
onlyItasisSeMet,
theto have a meth
total selenium content, plus an indication ofdeposition
its chemical
important
HMSeBA.
reserve
form,
but
more
as
the
determine their respective availability. When evaluating Se sources, it is also important to h
functional
form:
SeCys,
part HMSeBA
of the
guaranteed
stability in feed processing conditions
used
in the
industry.
or hydroxy
Conclusion
selenoproteins.
SeCysofshould
selenomethionine represents a pure, reliable
and stable source
organicthus
selenium.
be the best predictor of the efficacy
Although there are a large variety
Se sources
deposition
a reliable
evaluate
the source.
bio-efficacy
of various
Se sourc
selenium
Clearly,
the
ofTissue
selenium
on is
the
market, criteriaoftothe
organic
mineral form.
The objective
dietary Se(HMSeBA)
supplementation
is definitely
to enh
appeared
to be
most oforsuppliers
only provide
total of theOH-SeMet
Se
deposition
not only
the reserve
more as the
functional
form: SeCys,
theform,
mostbut
bio-available
form
of organic
selenium
content,
plusasanSeMet,
indication
selenoproteins.
thus be the best
the efficacy
of the selenium sour
Se topredictor
enhanceoftissue
SeCys contents
of its chemical SeCys
form. Itshould
is important
the OH-SeMet (HMSeBA) appeared to be the most bio-available form of organic Se to enha
even compared to other SeMet
to have a methodology to determine
SeCys contents even compared to other SeMet sources.
sources. AP
their respective availability. When
evaluating
Se
sources,
it
is
also
*Pierre-André Geraert ([email protected]) Director Innovation Marketing,
important to have a guaranteedResearch Manager AntiOxidants and Yves Mercier
([email protected])
stability in feed processing conditions
([email protected])
are with Adisseo France SAS. Y.G. Liu ([email protected]
used in the
industry.Services
HMSeBA&orBusiness Development, Adisseo Asia Pacific Pte Ltd. Refe
President,
Technical
*Pierre-André Geraert (pierre-andre.
available
from the authors. represents
hydroxy-selenomethionine
[email protected]) Director Innovation
a pure, reliable and stable source of
Marketing, Mickaël Briens, (mickael.
[email protected])
Research Manager
[file end]
organic selenium.
AntiOxidants and Yves Mercier (yves.
Tissue Se deposition is a reliable
[email protected]) are with Adisseo
criteria to evaluate the bio-efficacy
France SAS. Y.G. Liu (kevin.liu@adisseo.
com) is Vice President, Technical Services &
of various Se sources, either organic
Business Development, Adisseo Asia Pacific
or mineral form. The objective of
Pte Ltd. References are available from the
the dietary Se supplementation
authors.
ADISSEO Asia Pacific Pte Ltd I 30 Hill Street #03-03
Tel: +65 6543 1121 I Fax: +65 6545 3547 I www.adisseo.com I feeds
Comp
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29