J. Biomedical Science and Engineering, 2013, 6, 185-191 JBiSE
http://dx.doi.org/10.4236/jbise.2013.62022 Published Online February 2013 (http://www.scirp.org/journal/jbise/)
Effects of dietary CoQ10 and α-lipoic acid on CoQ10 levels
in plasma and tissues of eggs laying hens
Petra Jazbec Krizman, Andrej Smidovnik, Alenka Golc Wondra, Mitja Krizman, Mirko Prosek
National Institute of Chemistry, Ljubljana, Slovenia
Received 17 December 2012; revised 17 January 2013; accepted 23 January 2013
ABSTRACT
In this paper we described the effect of administrated
CoQ10, and alfa-lipoic acid on the concentration of
total CoQ10 in plasma end body tissues of eggs laying
hens. Organisms raise a complex network of enzymes,
metabolites and molecules with antioxidant activities
in order to prevent oxidative damage of theirs bodies.
Adequate blood concentrations of small weight mole-
cules ingested with food and food additives are im-
portant for the proper functioning of the antioxidant
defense. To test this hypothesis we prepared following
experiment. Forty weeks old hens were selected from
two genotypes; Ross 308 broiler mothers and Loh-
mann breed hens. Animals were fed for a period of 84
days. Concentrations of supplemented CoQ10 and A L A
were calculated from feed instruction tables so each
hen received an average of approximately 5 mg of
CoQ10 and 50 mg of ALA per kg of animal weight per
day. During the experiment blood samples were taken
and at the end of the experiment different body tis-
sues (heart, liver, breast, legs) were collected and ana-
lyzed with ori gina lly d eveloped HPLC-MS/MS metho d
based selective ionization with LiCl on MRM scan-
ning. We found a number of interesting and unex-
pected results. Supplemented CoQ10 increased con-
centrations of coenzyme CoQ10 in plasma and differ-
ent hen’s tissues. Increased concentration of CoQ10 is
the result of its transfer with chylomicrons from the
digestive tract to various organs of the body and to
the liver where exogenous and endogenous CoQ10 has
been re-redistributed through lipoproteins. Supple-
mented ALA caused much greater concentration of
CoQ10 in different tissues and plasma then CoQ10.
Plausible explanation of our results is such that ALA
may regenerates the antioxidants and accelerate the
formation of endogenous CoQ10 which is distributed
with lipoprotein carriers and increases overall con-
centration of CoQ10. Our experiments definitely show
that Lipoic acid beside glutathione promotes also a
synthesis of CoQ10 and increases the total concentra-
tion especially in liver and heart tissues.
Keywords: Laying Hens; Coenzyme Q10; α-Lipoic Acid;
Antioxidant Network; Fodder Additive
1. INTRODUCTION
Living organisms have to raise a complex system of en-
zymes, metabolites and molecules with antioxidant ac-
tivities in order to prevent oxidative damage of theirs
bodies [1,2]. Until recently, scientists believed that each
antioxidant worked separately, independently of the oth-
ers. Research performed at the Packer Lab at the Univer-
sity of California at Berkeley showed that there is a dy-
namic connection among certain key antioxidants. These
special antioxidants operate together and represent a dy-
namic defense of an organism. Antioxidants in this net-
work terminate oxidation processes by removing or
quenching free radicals and are capable of slowing or
preventing the oxidation [3].
The expression antioxidant network was first pre-
sented by Packer [4], who stated that antioxidants do not
act alone but are linked together into a network. Interac-
tion of antioxidants had been already noticed before
Packer, but he was the first who outlined a concept of a
network based on the five molecules; CoQ10, ascorbic
acid (vitamin C), tocopherol (vitamin E), glutathione and
lipoic acid. The diagram of the antioxidant network built
from reduced and oxidized forms of: lipoic acid, glu-
tathione, CoQ10, vitamin C and vitamin E is presented in
Figure 1. On the top at standard redox potential of less
than –0.315 V is the net supplied with protons from
NADH (the reduced form of Nicotinamide adenine dinu-
cleotide NAD+ a coenzyme found in all living cells), and
NADPH (the reduced form of Nicotinamide adenine di-
nucleotide phosphate NADP+). At –0.220 V FADH2 (the
reduced form of a redox cofactor flavin adenine dinu-
cleotide FAD involved in several important reactions in
metabolism) supports reduced form of CoQ10. In hydro-
philic phases a considerable protection is produced from
degradation product with antioxidant activity, like uric

P. J. Krizman et al. / J. Biomedical Science and Engineering 6 (2013) 185-191 186
Figure 1. The diagram of the antioxidant network built from reduced and oxidized forms of:
lipoic acid, glutation, CoQ10, vitamin C and vitamin E is presented. The net is embedded
between the endogenous cellular reduction system and exogenous antioxidants from a diet.
acid at +0.590 V.
Administered food may increase concentrations of vi-
tamins and coenzymes in the network. The antioxidants
from plants; carotenoids, flavonoids and polyphenols
also protect antioxidant network but only in the redox
range between +0.400 V and +0.700 V. From the Figure
1, it is possible to conclude that the operation of antioxi-
dant network is complex function [5-7], but also very
logical. Regeneration of net strongly depends on high
concentration of NADH and NADPH.
Our previous research work connected with industrial
poultry farming indicates the hypothesis that chickens
and hens could be very suitable candidates for scientific
estimation of the intensity of oxidative stress and protect-
tive effect of Low Molecular Weight Antioxidants [8,9].
The aim of this study was to determine the effects of a
scientifically selected diet on the content of several anti-
oxidants in blood plasma and some animal tissues. Ad-
ministered food provided necessary conditions for exis-
tence of adequate blood levels of enzymes, coenzymes,
which together with the large number of administered
small weight molecules were responsible for correct
functioning of body antioxidant defense. To test this hy-
pothesis we had to develop new reliable analytical meth-
ods for assessing the amount of antioxidants in plasma
and animal tissues. In present study the concentrations of
total amount of CoQ10 in different body tissues and blood
plasma of laying hens are presented. Oxidized form of
CoQ10 after prolonged feeding with food fortified with
CoQ10, and α-Lipoic acid (ALA) were measured with
originally developed HPLC-MS/MS method [10].
2. MATERIALS AND METHODS
2.1. Experimental Design
Forty weeks old hens were selected from two genotypes;
Ross 308 broiler mothers and Lohmann breed hens. Ani-
mals were housed in wire laying cage (one bird per cage)
and fed on the commercial feed NS-val (Ross) and NSK
(Lohmann) prepared in Perutnina Ptuj, Slovenia) for 2
weeks before the experiment started. Animals received
the supplemented diet on the first day of the experiment
and were fed for a period of 12 weeks. Concentrations of
supplemented CoQ10 and ALA were calculated from feed
instruction tables [11,12]. Each hen received an average
of approximately 5 mg of CoQ10 and (or) 50 mg of ALA

P. J. Krizman et al. / J. Biomedical Science and Engineering 6 (2013) 185-191 187
per kg of animal weight per day. During the 84 days pilot
raise, all animals were treated under identical environ-
mental and growing conditions. Tests were done in op-
timal breeding and healthy conditions. The required
amount of CoQ10 was provided as the water soluble addi-
tive originally synthesized in our laboratory (Laboratory
for Food Chemistry, National Institute of Chemistry,
Ljubljana, Slovenia) by in-capsulation of CoQ10 into corn
dextrin. The applied food grade alfa-lipoic acid and raw
CoQ10 were purchased from Linyi Tianliheng Trade Co
(China).
During the experiment the blood samples were taken
five times, at the start (day 1) and 21, 42, 63, and 84 days
after the experiment was introduced. Up to 2 ml of blood
were taken from vene cutaneae ulnaris. After the end of
the experiment hens were sacrificed and different body
tissues (heart, liver, breast, leg) were separated and stored
together with plasma end blood samples in cool storage
at −80˚C until the start of analyses.
All experimental procedures were done according to
the guidelines for the care and use of experimental ani-
mals at Biotechnical faculty, Department of Animal Sci-
ence, University of Ljubljana, Slovenia. Experiments on
animals were approved by Ethic Committee of the Min-
istry of Agriculture, Forestry and Food of the Republic
of Slovenia.
2.2. Materials and Methods
2.2.1. Che mi c al s
Methanol, ethanol, 2-propanol, 1,4-dioxane, acetonitrile,
hexane, perchloric acid and acetic acid (LC grade) were
supplied by Merck (Darmstadt, Germany). CoQ10 stan-
dard and Sodium borohydride were purchased from Sigma
Aldrich (Steinheim, Germany).
 -Cyclodextrin (food grade)
was supplied by Xi’an Hong Chang Pharmaceuticals Co.
(China), and CoQ10 (pharmaceuticals grade) by Linyi
Tianliheng Trade Co (China).
2.2.2. Experimental Procedures
Samples were prepared with following procedures: 400
µL of heparined blood was denaturated with 200 µL of
10% perchloric acid in ethanol. Analites were extracted
three times with 2 mL of n-hexane and the combined
organic extracts were concentrated with rotary evapora-
tor (Rotavapor R-144 Büchi, Switzerland). The residue
was dissolved again in 200 µL of 2-propanol and ana-
lyzed with HPLC-ESI-MS/MS.
Part of chicken breasts, legs, wings, whole hearts and
livers were mixed with H2O and homogenized for 3 min-
utes with Ultraturax at 20.000 rpm into a homogenous
paste. 10 g of the homogenized sample were weighed
into 50 mL centrifuge tube. 15 mL of warm (35˚C - 40
˚C) distilled water was added and intensively mixed for 5
minutes. Fat was extracted twice with 20 mL of solvent
mixture consisting of chloroform and methanol (2:1, v/v).
The combined extracts were concentrated and dried in a
stream of nitrogen. The oil residue was dissolved again
in 5 mL of 2-propanol.
Plasma and tissues concentrations of total CoQ10 were
quantified with Sciex API-4000 QTRAP LC/MS/MS sys-
tem from Applied Biosystems /MDS (Sciex Concord,
ON, Canada), equipped with TurboIonSprayTM ioniza-
tion system and connected to HPLC system constructed
from LDC Constametric 4100 pump, and SpectraSystem
AS3000 autosampler.
The reduced and oxidized form of CoQ10 were suc-
cessfully separated by LC column-LUNA C18 (2), 3 μm,
100 × 4.6 mm (Phenomenex, Torrance, CA, USA). Both
forms were eluted with an isocratic mobile phase (ace-
tonitrile: 2-propanol, 55:45) at a flow rate of 0.5 mL/min.
The injection volume was 2.0 µL. For efficient ionization
a solution of 0.5 µM LiCl (0.5 mL LiCl/L mobile phase)
was added directly into container of mobile phase. Sciex
Analyst software was used to perform data analysis and
peak integration.
2.2.3. Stati stical Anal ysi s
All statistics were run using Statgraphic plus Ver. 4. An
analysis of variance (ANOVA) and a Student t-test were
employed to evaluate differences between groups with
respect to plasma levels, and the relationship between
concentration levels and supplementation time.
3. RESULTS
Reliable quantitative determination of CoQ10 in biologi-
cal samples presented in Tables 1 and 2 was enabled
with HPLC-MS/MS analytical method based on im-
proved selective ionization of reduced and oxidized form
of CoQ10 with added LiCl, and scanning in MRM scan
mode. A quasi-molecular ion was formed with the added
lithium ion in positive ESI-MS ionization mode. The
parent ion for CoQ10 was 869.7 m/z (M + Li)+ and se-
lected fragment ion was 241.1 m/z. The linearity rang,
was from 0.02 to 5.0 mg/L (ppm), LOD was lower than
0.02 mg/kg and LOQ was 0.04 mg/kg. Obtained sensi-
tivity is nearly 50 times higher than the sensitivity of our
previously used analytical methods, mostly single step
HPLC-MS.
Nevertheless the new analytical method enables si-
multaneous determination of reduced and oxidized form,
we selected sample preparation with an oxidation step
and measured the total CoQ10. In this way effects of un-
controlled oxidation were eliminated [13].
The plasma levels of total CoQ10 in chicken’s and
hen’s plasma are shown in Table 1 and Figure 2. Some
results are taken from one of our previous study with

P. J. Krizman et al. / J. Biomedical Science and Engineering 6 (2013) 185-191 188
Table 1. CoQ10 content (mg/L) in the hens and chickens plasma
samples. (a) Hens (genotype Ross) started to administer 5 mg
CoQ10 or 50 mg lipoic acid in 37th week on day 266 and ex-
periment was stopped after 50 weeks on day 350; (b) Laying
hens (genotype Lohmann) started with fortified feed, (5 mg
CoQ10 or 50 mg lipoic acid) on 35th week and experiment was
stopped in 47th week; (c) CoQ10 content (mg/L) in the chicken
plasma (genotype Ross) after daily intake of CoQ10 (5 mg) and
lipoic acid (50 mg) on kg of body weight. Chickens started
with fortified feed on day 16 and experiment was stopped on
day 41.
(a)
CoQ10 (mg/L) sdx
Day of sampling
GControl 10
CoQ
G GALA
266 1.99 ± 0.46 2.13 ± 0.79 2.18 ± 0.64
287 1.82 ± 0.51 2.23 ± 0.91 2.78 ± 0.35
308 2.11 ± 0.63 2.50 ± 0.53 3.01 ± 0.75
329 1.77 ± 0.46 2.37 ± 0.42 2.86 ± 0.54
350 1.98 ± 0.38 2.38 ± 0.53 2.90 ± 0.86
(b)
CoQ10 (mg/L) sdx
Day of sampling
GControl 10
CoQ
G GALA
266 2.05 ± 0.801.98 ± 0.42 2.06 ± 0.34
287 2.10 ± 0.482.23 ± 0.68 3.04 ± 0.50
308 2.03 ± 0.492.29 ± 0.51 2.92 ± 0.75
329 2.20 ± 0.602.30 ± 0.28 2.95 ± 0.97
350 1.93 ± 0.222.38 ± 0.43 2.85 ± 0.76
(c)
CoQ10 (mg/L) sdx
Day of sampling
GControl 10
CoQ
G GALA
16 0.46 ± 0.06 0.47 ± 0.09 0.46 ± 0.09
28 0.59 ± 0.15 0.84 ± 0.33 0.94 ± 0.38
40 0.92 ± 0.26 1.78 ± 0.70 1.34 ± 0.13
chickens and demonstrate a constant increase of CoQ10
concentration in chicken plasma [9] during the first weeks
of chicken’s live. In the control group the starting con-
centration in day 16 was 0.46 mg/L and the final concen-
tration in day 40 was 0.92 mg/L. At the same time con-
centrations increased from 0.47 mg/L to 1.78 mg/L in the
group which administered CoQ10, and in the group fed
with ALA supplement, from 0.46 mg/L to 1.35 mg/L. A
similar trend was observed in the experiment with hens.
In the control group the level of CoQ10 was practically
constant, and the average plasma concentration was around
2.0 mg/L. In the test group administering CoQ10 the level
slightly increased, and the average concentration was
about 2.32 mg/L, at the same time in the ALA adminis-
tering group the average concentration was even higher,
2.75 mg/L. The increased plasma level in animals after
administering of CoQ10 was seen in many experiments
and was expected [14]. Meanwhile the high increase of
CoQ10 concentration in plasma after ALA supplementa-
tion was something new that we did not expect, because
so far in the literature was not possible to find such
information.
After many repeated experiments we have come to
believe that the results obtained are credible and logical
effect of ALA antioxidant protection. The research work
of Packer 1995, Han 1997 and Sen 1997 and some others
[15-17] showed that Lipoic acid could serve as a pro-
glutathione agent and could enhance the cellular level of
glutathione (GSH).
Our experiments show that Lipoic acid increases con-
centrations of CoQ10. From obtained results it was not
possible to conclude if the increased concentrations were
the result of boosted production of endogen CoQ10 or
improved protection of exogenous CoQ10. New updated
experiments will be needed if we want to clarify the
obtained results.
Now our opinion is that both options may be involved,
increased production in liver tissue and reduction of oxi-
dative stress which may additionally save the endogen
CoQ10. Our experiments have also shown that the increase
in CoQ10 plasma concentrations in young chickens is
greater than in adult hens during the supplementation
with CoQ10 and ALA. This result may be explained with
stronger oxidative stress to which laying hens are ex-
posed.
In Table 2 are presented concentrations of CoQ10 in
different tissues of laying hens. In our experiment two
genotypes Ross and Lohmann were used. Hans were
divided into three groups, control, CoQ10, and ALA
group. In each group there were 12 animals of each
genotype.
Concentrations of supplemented CoQ10 and ALA were
calculated and each hen received an average amount of
approximately 5 mg of CoQ10 or 50 mg of ALA per kg of
animal weight, per day. In one group 7 animals of each
genotype were selected and followed during the experi-
ment. Plasma, meat and organ samples were taken from
the same, at the start selected birds.
Measured values were evaluated in the two different
ways. In the first step each genotype was processed
separately. In the next step the average values taken from
the both genotypes were prepared. These values are
shown in Table 3.
We selected such solution, nevertheless some signifi-
cant differences were observed between two genotypes,
because we wanted to get enough reliable information
related to the difference between supplementation with
CoQ10 and ALA, regardless of genotype.
Measured values were evaluated in the two different

P. J. Krizman et al. / J. Biomedical Science and Engineering 6 (2013) 185-191 189
Table 2. Concentration of CoQ10 in different hens tissues after 84 days of supplementation with CoQ10 and ALA.
Tissue Genotype Control
Conc. (mg/kg)
+CoQ10
Conc. (mg/kg)
+ALA
Conc. (mg/kg)
Ross 53.7 ± 3.2 48.4 ± 4.5 64.6 ± 9.8
Liver Lohman 56.1 ± 8.3 59.2 ± 3.6 58.3 ± 14.0
mean 54.9 ± 1.7 53.8 ± 7.6 61.5 ± 5.4
Ross 55.6 ± 11.6 50.6 ± 10.6 52.4 ± 4.5
Heart Lohman 51.9 ± 4.2 56.7 ± 10.2 60.2 ± 14.2
mean 53.8 ± 2.6 53.6 ± 4.3 57.2 ± 6.8
Ross 12.3 ± 1.5 12.3 ± 1.8 14.0 ± 2.7
Breast Lohman 10.6 ± 0.7 12.1 ± 1.9 12.7 ± 1.3
mean 11.4 ± 1.2 12.2 ± 1.2 13.4 ± 0.9
Ross 17.2 ± 1.3 18.1 ± 4.7 19.1 ± 4.4
Leg Lohman 23.5 ± 3.1 26.6 ± 1.7 28.4 ± 0.7
mean 20.4 ± 4.4 22.4 ± 6.0 23.8 ± 6.5
Ross 1,87 ± 0.42 2.37 ± 0.47 2.75 ± 0.69
plasma Lohman 2.06 ± 0.41 2.22 ± 0.34 2.76 ± 0.87
mean 1.97 ± 0.18 2.30 ± 0.09 2.76 ± 0.04
increase of nearly 10% was recorded. The highest in-
crease was seen in plasma, nearly 15%. In the test group
which administered ALA the increase of CoQ10 was
much higher than in coenzyme group. In heart tissue the
final level of CoQ10 was more than 5% and in liver more
than 10% higher than in the control group. Concentra-
tions in meat tissues were very high, more than 15% and
in plasma nearly 40% higher than in control group. The
same trend is seen in both genotypes groups. Lipoic acid
produces much higher concentration of CoQ10 then sup-
plemented CoQ10 alone. It is interesting that Lohmann
hens have much higher response with both supplements.
It is also unexpected that concentrations in heart and
liver are not increased, in reality in some cases they are
even reduced. We explain these results with the influence
of oxidative stress which is obviously higher in the Ross
group then in the Lohmann group. Our results also show
that higher concentration of CoQ10 in plasma does not
automatically mean high concentrations of CoQ10 in tis-
sues.
Figure 2. CoQ10 content (mg/L) in the plasma of broilers and
hens genotype Ross, results are taken from two consecutive
experiments. Animals were fed with different fodder additives.
Applied labels: (—○—) control group; (—●—) 5 mg CoQ10;
(—Δ—) 50 mg ALA on 1 kg of birds weight approximately.
ways. In the first step each genotype was processed
separately. In the next step the average values taken from
the both genotypes were prepared. These values are
shown in Figure 3. We selected such solution, neverthe-
less some significant differences were observed between
two genotypes, because we wanted to get enough reliable
information related to the difference between supple-
mentation with CoQ10 and ALA, regardless of genotype.
Calculated values represent the amount of CoQ10 in con-
trol group and two experimental groups. They were ob-
tained from measured concentrations (mg/kg) multiplied
with estimated weights from instruction tables (kg) of
processed organs and meat tissues.
We tried to clarify the link between distribution, ac-
cumulation, and elimination of exogenous and endoge-
nous CoQ10 in animal tissues with a help of a model. We
wanted to determine if eaten lipoic acid busted a produc-
tion of new CoQ10 or only eliminate oxidation of it.
Concentrations of processed tissues were taken from our
experiments. The exogenous CoQ10 was transported from
column to liver with chylomicrons where it was pre-
packed to Apoproteins and redistributed through the body.
In both transport paths, lipoic acid may prevented the
decomposition of coenzyme. It also restored certain liver
functions [18,19] and in this way boosted the synthesis,
which increased the overall concentration of CoQ10. In
In our experiments supplemented CoQ10 was not ac-
cumulated in liver and heart, but in legs and breasts. An

P. J. Krizman et al. / J. Biomedical Science and Engineering 6 (2013) 185-191 190
Figure 3. Average CoQ10 levels in tissues and plasma of laying hens in control group and
after oral administration of CoQ10 and ALA are shown. Increased concentrations of CoQ10
are expressed in percent.
Table 3. Calculated values (mg/unit) of CoQ10 in different organs and body parts of hens of Ross and Lohmann genotype are shown.
Measured concentrations of CoQ10 (mg/kg) were multiplied with estimated weight of selected body parts.
Samples Control group Supplemented CoQ10 Supplemented ALA
Weight
(g)
*CoQ10
mg/kg
CoQ10
mg
*CoQ10
mg/kg
CoQ10
mg
Diff.
%
*CoQ10
mg/kg
CoQ10
mg
Diff.
%
Legs R 750 17.2 12.91 18.1 13.59 105.3 19.2 14.37 111.3
Breast R 550 12.3 6.74 12.3 6.77 100.5 14.0 7.70 114.2
Liver R 50 53.6 2.68 48.4 2.42 90.3 64.6 3.23 120.5
Hearth R 25 55.6 2.78 50.6 2.53 90.9 52.4 2.62 94.2
Blood R 250 1.9 0.97 2.3 1.16 120.2 2.75 1.37 142.1
∑ Ross 1625 26.08 26.48 101.5 29.30 112.3
Legs L 375 23.5 8.81 26.6 9.98 113.3 28.4 10.66 120.9
Breast L 330 10.6 3.49 12.0 3.97 113.9 12.7 4.19 120.0
Liver L 30 56.1 1.68 59.2 1.78 105.5 58.3 1.75 103.9
Hearth L 15 51.9 1.17 56.7 1.28 109.2 62.0 1.40 119.4
Blood L 150 2.1 0.46 2.3 0.51 109.3 2.76 0.62 134.1
∑ Lohmann 900 15.62 17.52 112.2 18.61 119.2

P. J. Krizman et al. / J. Biomedical Science and Engineering 6 (2013) 185-191 191
cells Lipoic acid took care of antioxidant network and
protected lipid membranes by elimination of uncontrolled
oxidation which resulted in higher levels of CoQ10.
Nevertheless the correlations between measured and
calculated values were good, we were not able to con-
clude which previously described option was prevalent,
and further experiments are necessary.
4. CONCLUSION
Lipoic acid is the most potent member of antioxidant
protection in a body. With electric potential of (−320 mV)
it may regenerate all other antioxidants. Results undoubt-
edly confirm the existence of an antioxidant network and
synergistic effect of administered low weight substances.
Our work demonstrates that ALA is able to influence not
only on the regeneration of glutathione but according to
our results also on regeneration of CoQ10.
5. ACKNOWLEDGEMENTS
This work was supported by the Slovenian Research Agency (Research
Project L1-2174) and the Perutnina Ptuj, d.d.. The authors wish to
thank, Prof. Dr. Antonija Holcman and Prof. Dr. Marko Volk for their
support in experiments with animals.
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