Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : January 28, 2024
Accepted : March 19 2024
Published online : March 31, 2024
doi:10.24659/gsr.11.1_51

Original article

Effects of ostrich meat intake on amino acid metabolism and growth hormone
secretion: A clinical trial by repeated measurement
Yoshikazu Yonei * 1), Mari Ogura * 1, 2), Masayuki Yagi 1), Ikuro Kawasaki 1), Chieko Sakiyama 1),
Yoshiko Kawaguchi 3), Masayuki Kurokawa 3), Tomoko Tsuji 3)* equally contributed
1) Anti-Aging Medical Research Center and Glycative Stress Research Center,
Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan
2) Department of Food and Nutrition, Kyoto Bunkyo Junior College, Kyoto, Japan3) Yoshinoya Holdings Co., Ltd, Tokyo, Japan

Abstract

Purpose: Chicken (especially breast meat) is a popular food for health-conscious people due to its low fat and high protein
content. In this study, we focused on ostrich meat (OM), which is attracting attention from the perspective of Sustainable
Development Goals (SDGs), and examined changes in blood amino acid composition after consumption, and compared it withblood composition after consuming chicken meat (CM).
Methods: The subjects were 9 healthy men and women (2 men, 7 women, 23.0 ± 1.2 years old, BMI 20.1 ± 2.2). The test
foods were OM food and CM (breast meat) food with adjusted protein content (20 g). CM food was consumed for the first 7
days and after a 1-month rest period, the subjects started taking OM for the latter 7 days. Blood tests were then performed at
1 day and 7 days after intake, respectively.
Results: Seven days after ingesting the test food, the plasma amino acid composition showed a significant increase in taurine
with OM intake, and a slight increase in citrulline and 3-methylhistidine with CM intake, while there was no difference in the
total amino acid content. There was no difference in plasma aldehyde (3-deoxyglucosone, glyoxal, methylglyoxal) between
the two groups, showing no difference in aldehyde trapping effect. Peripheral blood tests showed that the red blood cell count,hemoglobin content, and hematocrit value decreased by 3 to 5 % when CM was ingested due to iron loss by blood sampling,whereas this was alleviated when OM, which has a high iron content, was ingested. No adverse events were observed during
the study period.
Conclusion: Among high-protein, low-fat avian meats, ostrich meat is richer in taurine and iron than chicken breast, making
it a useful food for health-conscious people.

KEY WORDS: ostrich meat, amino acids, taurine, iron, glycative stress

Introduction
In recent years, when considering the food situation,
we have entered an era in which it is necessary to consider
contributions to improving nutritional status and reducing
the risk of starvation on a global scale. Plant-based foods
made from legumes and cultured mycelium, which are more
efficiently produced as protein foods than grain-fed meat,
are also being researched as new food resources with low
environmental impact. The ostrich used in this study has

a low environmental impact and is a sustainable livestock.
Flightless birds such as ostriches are called “ratites” andbelong to the taxonomic group “paleognathians”. Ostriches,found in Africa, were the first of the modern paleognathians
to diverge from other species. The flightlessness of ratites
is not necessarily due to their primitive nature, but rather asa result of them adapting to life on the ground in order tosurvive 1, 2).
The ostrich, which evolved to survive on the Africansavannah, has a long intestine and excellent digestive ability,

Contact Address: Professor Yoshikazu Yonei, MD, PhD
Anti-Aging Medical Research Center,
Graduate School of Life and Medical Sciences, Doshisha University
1- 3, Tatara Miyakodani, Kyotanabe, Kyoto, 610- 0394 Japan
TEL & FAX: +81-774-65-6394 e -mail: yyonei@mail.doshisha.ac.jp
Co-authors: Ogura M, m-ogura@po.kbu.ac.jp; Yagi M, yagi@yonei-labo.com;
Kawasaki I, ctuh2011@mail4.doshisha.ac.jp; Sakiyama C, csakiyam@mail.doshisha.ac.jp;
Kawaguchi Y, y.kawaguchi@yoshinoya.com; Kurokawa M, m.kurokawa@yoshinoya.com;
Tsuji T, t.tsuji@yoshinoya.com_ 51 _

Glycative Stress Research 2024; 11 (1): 51-61(c) Society for Glycative Stress ResearchOstrich Meat Consumption and Plasma Amino Acids

and its abundance of intestinal bacteria produces a large
amount of amino acids, allowing it to absorb nutrients withhigh efficiency. According to the Ministry of Agriculture,
Forestry and Fisheries document “ Did you know? Japan's
food situation”, the amount of grain (corn equivalent)
required to produce 1 kg of livestock products is 11 kg forbeef, 7 kg for pork, and 4 kg for chicken 3). On the other hand,
ostrich meat requires 4 kg of grain (calculated based on theassumption that 40 kg of meat can be obtained from 100
kg of ostrich). However, the main feed is not grains such as
corn, so the advantage is that the feed is inedible for humans(e.g., grass and vegetable scraps from food factories).
Regarding skeletal muscles, the wing and pectoral
muscles have degenerated, but the skeletal muscles of theskeleton, thighs, and hips have evolved to enhance runningability in order to escape from natural enemies 4, 5). Therefore,
ostrich thigh meat may contain nutritional components that
help maintain muscle strength and endurance. In this study,
we investigated changes in blood amino acid composition
when ostrich meat was ingested and compared it with blood
composition after ingesting chicken meat.

MethodTest implementation system

This study was evaluated by an ethics review committee
consisting of a third party not involved in the study, in orderto ensure the human rights and safety of test participants andthe reliability of test data. The Ethics Review Committee for
Research Involving Human Subjects of the Glycation StressResearch Association approved this study (approval number
2022-007, November 7, 2022). The study was conducted from
December 2022 to January 2023 at the Anti-Aging ResearchCenter, Faculty of Biomedical Sciences, Doshisha University(principal investigator: Yoshikazu Yonei) based on the study
implementation plan (UMIN study ID: UMIN000049501).
In conducting the study, we complied with ethical principles
based on the Declaration of Helsinki (amended at the 2013
WMA Fortaleza General Meeting “ Brazil” ) and the ethicalguidelines for life science and medical research involving
human subjects ( Notification No. 1 of the Ministry of
Education, Culture, Sports, Science and Technology, Ministryof Health, Labor and Welfare, and Ministry of Economy,
Trade and Industry, 2021).

5) Those who regularly consume high protein foods such asprotein powder.
6) Those who are pregnant, breastfeeding, or may become
pregnant.
7) Those who are currently participating in another humanclinical trial, or 3 months have passed since participating
in another human clinical trial.
8) Those who regularly take the following supplements/
health foods (e.g., vitamins, folic acid, iron).
9) Other individuals who are judged by the study director to
be inappropriate as subjects for this study
This study started with 9 people, and on the final testday (Visit-6), 2 people were unable to undergo the test due
to reasons unrelated to this study. All test subjects were
included in the analysis at the post- test case review meeting,and any data that could not be collected were treated as
missing data.

Study design

As test foods, ham (protein amount 20 g) with ostrich
meat (Yoshinoya Holdings Co., Ltd., Tokyo, Japan) wasused as ostrich meat meal (OM) (Fig. 1 ), and Salad chicken(commercial product, protein content 20 g) with chicken
breast meat (CM) was used as a control meal. The nutritional
components of OM and CM are shown in Table 1. Table 2
shows the amino acid content per 100 g of OM.
The test schedule is shown in Fig. 2. First, subjects
were given a designated basic meal (BM, 200 g of steamed
rice and a rice seasoning topping) and a cup of miso soup

Subject

After conducting a study briefing session, nine healthy
men and women between the ages of 20 and 40 who had
given prior written consent to participate in this study andwho did not meet the following exclusion criteria were
included as subjects.
1) Those who are currently suffering from some kind of
disease and are receiving drug treatment.
2) Persons with a past or current history of serious disordersof the liver, kidneys, heart, lungs, blood, etc.
3) Subjects with severe anemia.
4) Persons who may develop allergic symptoms to test foods,
or those who may develop severe allergic symptoms toother foods or medicines.

_ 52 _

Fig. 1. Appearance of test food (ostrich meat).
Table 1. Nutritional composition.

Water (g)Energy (kcal)
Protein (g)Carbohydrate (g)Fat (g)Sodium (mg)Control food
Steamed chicken(87 g)

Test food
Smoked ham(91 g)

6 2.4
96
20.0
1.6
1.1
282

6 2.2
112
20.0
4.4
1.5
783

Glycative Stress Researchfor dinner on the day before the test (– 1 day) and on the dayof the test (day 0, Visit -1 and Visit-4). Subjects came to thefacility without ingesting breakfast on the day they started
taking the test food ( Visit-2 and Visit-5), and after coming
to the facility, they ingested OM ( Visit-5) or CM (Visit-2)
along with BM. For the following 5 days, subjects consumed
OM or CM with BM at breakfast. For dinner on the 6 thday, they ingested the same BM and a cup of miso soup as
on day –1 and 0, and on the 7 th day of intake, they came tothe facility without having breakfast (Visit-3 and Visit- 6),
and after coming to the facility, they ingested OM ( Visit- 6)
or CM (Visit-3) along with BM. For Visit-1 and Visit- 4,
physical measurements and blood samples were taken after
the visit. For Visit-2, Visit-3, Visit-5, and Visit- 6, after

physical measurements were taken, the test food was ingested
as described above, and after a 3-hour waiting period, blood
samples were obtained.

Evaluation item

Body measurements
Physical measurements included height, weight, bodyfat percentage, and body mass index (BMI). A TANITA
multi-frequency body composition meter MC-780A-N
portable type ( Tanita Co., Ltd., Tokyo) was used for bodycomposition testing.
Blood test
Peripheral blood tests and biochemical tests were
performed using blood samples. The evaluation items
this time were amino acid analysis, vitamin B12, glucose,
plasma aldehyde (3- deoxyglucosone; 3D G, glyoxal; GO,methylglyoxal; MGO), and peripheral hematology tests (whiteblood cell count [ WBC], red blood cell count [RBC],
hemoglobin [Hb], hematocrit [Ht], mean corpuscularvolume [ MCV ], mean corpuscular hemoglobin [MCH],
mean corpuscular hemoglobin concentration [MCHC],
platelet count). Among the tests using blood samples, blood
aldehyde was measured at the Glycation Stress ResearchCenter, Faculty of Biomedical Sciences, Doshisha University(Kyotanabe, Kyoto, Japan), and other items were measured at
LSI Medience Co., Ltd. (Tokyo, Japan).

Table 2. Amino acid composition.
Amino acid content per 100 g ostrich meat
Arginine
LysineHistidine
Phenylalanine
Tyrosine
LeucineIsoleucine
Methionine
ValineAlanineGlycineProlineGlutamic acid
SerineThreonine
Aspartic acid
Tryptophan
CystineTaurine1.32 g1.85 g0.56 g0.94 g0.73 g0.75 g1.02 g0.55 g1.08 g1.23 g0.93 g0.91 g3.78 g0.94 g0.98 g1.91 g0.29 g0.27 g0.12 gday – 1
Breakfast
Phase Ⅰ

Visit - 1
day 0

Meals as usual

Visit - 2
day 1

day 2

No
meal ※

Designated meals

day 5

day 6

day 7

No
meal ※

Visit - 4
day 0

Meals as usual

Designatedmeals

Meals as usual
Visit - 5
day 1

day 2

No
meal ※

day 3

day 4

day 5

day 6

Meals
as usual
Visit - 6
day 7

Nomeal ※

OM + Steamed rice
Meals as usual

Lunch
Dinnerday 4

Visit - 3

Meals as usual

day – 1
Breakfastday 3

Steamed chicken + Steamed rice

Lunch
DinnerPhase II

Statistical analysis
Statistical analysis was performed using the statisticalanalysis software Excel Statistics (Social Information Service,
Tokyo). Paired t test was used for comparative analysis with
Day 0. Student’s t test was used for between-group analysis.
A significant difference was defined as a risk rate of lessthan 5%. No outliers were set. However, if data could not
be obtained due to testing problems, or if there were major
problems with the reliability of the data, they were treated as
missing values and no alternative values were used.

Designated meals

Meals as usualFig. 2. The test schedule.

Designated
meals

Meals
as usual

No meal ※ = Participants did not eat at home, but took the test meal (Steamed chicken+Steamed rice or OM+Steamed rice) aftercoming to the testing site. OM, ostrich meat.

_ 53 _

Ostrich Meat Consumption and Plasma Amino Acids

ResultPlasma aldehydes (3DG, GO, MGO)

General backgroundThe general background of the 9 subjects for analysis
was 2 males and 7 females, age 23.0 ± 1.2 years, height162.0 ± 7.7 cm, weight 52.7 ± 6.6 kg, body fat percentage
26.0 ± 6.6 %, and BMI 20.1 ± 2.2 ( Table 3 ).

Table 3. Anthropometry.
Mean
year

23.0

±

1.2

Heightcm

16 2.0±7.7

Weight

kg

52.7

±

6.6

Body fat

%

26.0

±

6.6

20.1

±

2.2

BMI

Hematological tests

SD

Age

n = 9. BMI, body mass index; SD, standard deviation.

Amino acid analysis

Table 4 and Fig. 3 show the results of plasma amino acidanalysis. The blood amino acid analysis at each visit showed
that, in the OM intake group, the amino acids (taurine,
threonine, asparagine, proline, glycine, alanine, citrulline,
valine, cystine, methionine, isoleucine, leucine, tyrosine,β-alanine, phenylalanine, ornithine, 1-methylhistidine,
histidine, lysine, 3-methylhistidine, tryptophan, and arginine)significantly increased on the first day of intake (day 1, Visit-5)
and on the 7th day of intake (day 7, Visit-6) compared tobefore intake (day 0, Visit- 4). In addition, the glutamineand Fisher ratios significantly increased on day 7 ( Visit- 6 )compared to day 0 ( Visit- 4).
On the 7 th day of intake, significant differences wereobserved between the OM intake group and the CM intake
group in taurine, citrulline, and 3-methylhistidine. Taurine
was increased in the OM intake group on both days 1 (Visit-2,
5) and day 7 (Visit - 3, 6, p < 0.01). 3-Methylhistidine wassignificantly increased ( p < 0.01) on the day 1 (Visit -2, 5)
and day 7 ( Visit -3, 6), but the amount of change was slight.
A significant increase in citrulline was observed in the CM
intake group on day 7 (Visits -3 and 6, p < 0.5). There was nodifference in total amino acid content (sum of measurement
items) between the two groups.

Vitamin B12

Vitamin B12 significantly increased on day 7 of CM
intake (Visit-3) compared to day 0 ( Visit-1), but there wasno significant difference between groups compared to the
OM intake group ( Table 5 ).

Blood glucose (PG)

Among blood aldehydes, no significant changes wereobserved in 3DG and GO in both the OM and CM intake
groups. MGO significantly increased on day 1 (Visit-2) andday 7 (Visit-3) of CM intake compared to day 0 (Visit-1).
There were no differences between groups in the amount ofchange for any item ( Table 6 ).

Blood glucose (PG) significantly decreased on day 1 of
OM intake (Visit-5) compared to day 0 (Visit-4), and there
was a significant difference between groups compared to the
CM intake group (p < 0.01, Table 5 ). The CM intake group
showed a significant decrease on day 7 (Visit-3) compared
to day 0 (Visit-1), but there was no significant difference
between the groups.

Changes in peripheral blood are shown in Table 7 andFig. 4. In the CM intake group, the RBC count, Hb content,
and Ht on day 1 (Visit-2) and day 7 (Visit-3) significantly
decreased compared to day 0 (Visit-1). The effect remainedeven on day 7; the rate change rate was −3. 4 % in RBC,
− 5.0 % in Hb content, and −3.4 % in Ht.
On the other hand, the decrease in these three items
was alleviated in the OM intake group. The RBC count wassignificantly decreased on the first day (Visit-5) compared
to before intake (Visit-4) (Fig. 4-a ). No significant decrease
was observed on day 7 ( Visit-6). No significant decrease in
Hb or Ht was observed at any time point compared to day 0(Visit-4) (Fig. 4-b, c ).
In a group comparison with the CM intake group, there
was no significant difference in RBC on day 7 (Visit- 6) ofintake. It was shown that the decrease in the OM intake
group was significantly alleviated on day 1 of RBC (Visit-5),
and on day 1 and day 7 of Hb and RBC (Visit-5, 7).
MCV significantly increased only on day 7 of OM
intake (Visit- 6) compared to day 0 (Visit-4) with a significant
difference between the groups ( Fig. 4-d ).

Discussion

Summary of results

The main goal of this study is to observe the changes
in blood amino acids due to the intake of ostrich meat (20 gof protein) and to compare it with that of chicken meat (20g of protein). The subjects were 9 healthy men and women(2 men, 7 women, 23.1 ± 1. 2 years old, BMI 20.1 ± 2.2).
The first half was one week of CM intake, and after a rest
period (one month), the second half was OM intake. Bloodbiochemical tests including plasma amino acid analysis
were performed, and a comparative analysis was performed
between the OM intake group and the CM intake group.
As a result of plasma amino acid analysis, there wasno difference in the total amount between the OM intake
group and the CM intake group, but an increase in taurine
concentration was observed in the OM intake groupregarding the composition.
Since there was no difference in plasma aldehyde (3DG,
GO, MGO) between the two groups, there was no difference
in aldehyde trapping effect. When there is postprandial
hyperglycemia, multiple types of aldehyde-producing chain
reactions (aldehyde sparks) occur, which induce alkylationand carbonylation modifications to proteins in the bloodand cells. However, as the total amino acids increased afteringesting the test food, both OM and CM are excellent foodsin that they can be expected to have an aldehyde trapping
effect.

_ 54 _Glycative Stress Research

Table 4. Plasma amino acid concentration.
Before and after analysis
Group

Before intake (day 0)nTaurinenmol/mL

Hydroxyproline *nmol/mL

Threoninenmol/mL

Serinenmol/mL

Asparagine

nmol/mL

Glutamine

nmol/mL

Glutamic acidnmol/mL

Prolinenmol/mL

Glycinenmol/mL

Alaninenmol/mL

Citrulline

nmol/mL

α -Amino- n butyric acidnmol/mL

Valinenmol/mL

Cystinenmol/mL

Methionine

nmol/mL

Isoleucine

nmol/mL

Leucinenmol/mL

Tyrosine

nmol/mL

Alanine *nmol/mL

Phenylalanine

nmol/mL

Monoethanolamine

nmol/mL

Ornithine

nmol/mL

1-Methylhistidine * nmol/mL
Histidine

nmol/mL

Lysinenmol/mL

3- Methylhistidine * nmol/mL
Tryptophan

nmol/mL

Arginine

nmol/mL

Fischer ratio

nmol/mL

OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM
OM
CM

9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9

Mean

SD

45.38 ± 4.54
45.54 ± 3.00
11.73 ± 9.35
8.31 ± 2.28
128.37 ± 27.04
111.39 ± 26.19
130.58 ± 22.80
121.87 ± 13.67
47.60 ± 6.66
45.04 ± 5.04
22.69 ± 6.80
19.34 ± 4.71
534.03 ± 68.40
500.97 ± 64.50
140.16 ± 37.75
136.19 ± 46.98
233.74 ± 46.51
214.47 ± 27.72
355.99 ± 82.39
342.46 ± 94.89
25.52 ± 3.14
24.00 ± 4.16
21.38 ± 4.78
19.43 ± 7.71
204.36 ± 25.92
190.30 ± 24.60
37.97 ± 6.44
33.80 ± 5.74
27.87 ± 3.61
26.37 ± 3.59
62.74 ± 8.53
53.14 ± 9.23
109.44 ± 14.52
107.59 ± 16.54
63.77 ± 8.20
57.74 ± 7.51
5.30 ± 0.00
7.56 ± 0.77
61.21 ± 7.34
60.30 ± 7.56
9.02 ± 1.38
9.29 ± 0.81
57.19 ± 12.83
65.32 ± 11.94
14.38 ± 6.17
9.87 ± 5.41
85.62 ± 13.87
86.01 ± 8.06
158.62 ± 18.47
153.36 ± 24.04
6.00 ± 0.00
5.30 ± 0.00
70.37 ± 15.50
70.06 ± 14.24
82.92 ± 17.36
64.07 ± 17.85
3.04 ± 0.44
2.99 ± 0.31

day 1

Between-group analysis

vs day 0

n

Mean

9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9

59.22 ± 8.02
51.49 ± 5.57
9.41 ± 2.66
10.92 ± 1.99
162.84 ± 29.53
176.14 ± 34.11
138.27 ± 25.40
152.79 ± 26.93
64.47 ± 8.82
68.04 ± 13.42
18.41 ± 3.54
23.32 ± 4.28
556.99 ± 51.19
603.58 ± 72.86
169.91 ± 30.81
183.94 ± 47.05
257.37 ± 48.08
282.19 ± 44.70
426.56 ± 58.66
468.60 ± 57.97
29.91 ± 6.42
33.76 ± 6.95
20.57 ± 4.16
22.07 ± 7.34
263.79 ± 27.75
306.29 ± 29.35
34.08 ± 6.38
40.07 ± 6.08
42.76 ± 6.32
45.23 ± 8.84
101.76 ± 17.80
116.47 ± 20.99
158.41 ± 24.81
179.30 ± 30.00
81.42 ± 15.56
86.80 ± 11.73
17.96 ± 4.41
26.14 ± 5.58
77.79 ± 7.29
78.57 ± 8.64
9.02 ± 0.98
9.68 ± 1.21
88.41 ± 20.06
93.14 ± 17.48
33.04 ± 6.64
39.43 ± 6.47
95.20 ± 10.75
111.20 ± 18.31
256.93 ± 17.76
285.84 ± 53.35
5.92 ± 0.75
7.01 ± 0.96
80.21 ± 10.55
87.99 ± 7.17
120.31 ± 15.79
128.27 ± 34.58
3.31 ± 0.34
3.65 ± 0.33

SD

day 7

p value

n

Mean

0.000
0.003
0.453
0.008
0.001
0.000
0.130
0.005
0.000
0.001
0.092
0.001
0.105
0.003
0.007
0.001
0.042
0.002
0.007
0.004
0.044
0.002
0.367
0.042
0.002
0.000
0.000
0.015
0.000
0.000
0.000
0.000
0.001
0.001
0.008
0.000
0.000
0.000
0.000
0.001
1.000
0.313
0.000
0.001
0.000
0.000
0.008
0.003
0.000
0.000
0.027
0.000
0.014
0.003
0.000
0.000
0.082
0.000

7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
9
7
7

70.17 ± 6.68
49.70 ± 6.22
12.66 ± 6.96
10.91 ± 2.99
170.89 ± 47.13
177.20 ± 34.48
138.57 ± 29.11
139.51 ± 25.17
69.39 ± 14.14
63.70 ± 12.96
21.06 ± 5.80
20.84 ± 4.91
607.99 ± 78.28
615.40 ± 78.43
184.71 ± 40.88
183.43 ± 43.51
255.30 ± 37.70
253.10 ± 52.39
452.86 ± 91.19
461.09 ± 66.96
32.03 ± 5.55
37.27 ± 6.52
21.69 ± 5.38
19.41 ± 3.92
317.89 ± 46.54
334.10 ± 47.93
45.09 ± 6.87
38.72 ± 5.80
46.60 ± 7.42
45.08 ± 10.81
126.77 ± 23.50
123.57 ± 26.12
194.99 ± 29.30
185.06 ± 34.10
90.44 ± 11.44
96.83 ± 20.26
22.01 ± 3.40
24.62 ± 7.46
89.30 ± 12.07
84.06 ± 11.85
9.01 ± 0.69
9.22 ± 0.88
95.47 ± 25.78
91.90 ± 19.29
45.63 ± 6.67
50.06 ± 8.54
108.53 ± 13.96
108.54 ± 14.87
298.71 ± 34.02
282.17 ± 52.08
6.64 ± 0.80
8.58 ± 0.96
91.07 ± 8.74
97.59 ± 10.36
126.29 ± 26.34
133.19 ± 37.61
3.55 ± 0.26
3.59 ± 0.43

SDvs day 0

day 1

day 7

p valuep valuep value

0.009

0.000

0.102

0.719

0.018

0.297

0.022

0.522

0.268

0.474

0.003

0.064

0.011

0.520

0.157

0.437

0.027

0.533

0.159

0.673

0.077

0.045

0.024

0.872

0.012

0.329

0.000

0.177

0.311

0.862

0.041

0.654

0.186

0.575

0.126

0.217

0.042

0.998

0.673

0.262

0.467

0.617

0.639

0.239

0.032

0.108

0.033

0.433

0.166

0.544

0.000

0.000

0.151

0.760

0.050

0.242

0.034

0.541

0.000
0.089
0.195
0.044
0.008
0.002
0.161
0.070
0.001
0.003
0.168
0.264
0.022
0.002
0.001
0.002
0.036
0.025
0.013
0.010
0.004
0.000
0.857
0.989
0.001
0.000
0.004
0.022
0.000
0.001
0.001
0.000
0.000
0.001
0.000
0.000
0.000
0.000
0.000
0.000
0.736
0.713
0.004
0.006
0.000
0.000
0.000
0.000
0.000
0.000
0.019
0.000
0.010
0.003
0.002
0.001
0.049
0.001

* Statistical analysis was performed using input values due to the data below the detection sensitivity. Paired t test was used for comparative analysis with
Day 0. Student’s t test was used for between-group analysis. OM, ostrich meat; CM, chicken meat; SD, standard deviation.

_ 55 _

Ostrich Meat Consumption and Plasma Amino Acids**

TaurineThreonine
Asparagine
Glutamine
ProlineGlycine
AlanineCitrulline*

ValineMethionine
Isoleucine
LeucineTyrosineß-Alanine
Phenylalanine
Ornithine
1-Methylhistidine
Histidine
Lysine3-Methylhistidine
Tryptophan**

Arginine

0.0

50.0

100.0
OM

150.0
CM

Fig. 3. Changes in plasma amino acids on day 7 of intake.

200.0

250.0
(nmol/mL)

Results are expressed as mean ± SD. * p < 0.05, ** p < 0.01 by Student’s t test, n = 9. OM, ostrich meat; CM, chicken
meat; SD, standard deviation.

_ 56 _Glycative Stress Research

Table 5. Plasma vitamin B12 and glucose concentration.
Before and after analysis
Group

Vitamine B12

pg/mL

Glucosemg/dL

Before intake (day 0)

day 1

SD

n

Mean

Between-group analysis

vs day 0
SD

day 7
Mean

SD

vs day 0

day 1

day 7

p valuep valuep value

0.848

0.151

0.000

0.223

n

Mean

p valuenOM9488.78 ± 122.35

9 523.44 ± 139.04

0.343

7 574.29 ± 190.35

0.382

CM

9

503.67 ± 237.27

9 547.11 ± 232.63

0.173

9 620.67 ± 304.24

0.005

OM

9

80.89 ± 5.15

965.56 ± 9.92

0.000

7

80.29 ± 12.54

0.762

CM

9

79.44 ± 5.23

981.89 ± 7.72

0.337

9

72.11 ± 6.92

0.009

Paired t test was used for comparative analysis with Day 0. Student’s t test was used for between-group analysis. OM, ostrich meat; CM, chicken meat;SD, standard deviation.

Table 6. Plasma aldehyde concentration.
Before and after analysis
Group

3DG

μg/mL

GO

μg/mL

MGO

μg/mL

Before intake (day 0)

day 1

SD

Between-group analysis

vs day 0

n

Mean

n

Mean

OM

9

0.098 ± 0.028

9

0.096 ± 0.025

SD

CM

9

0.087 ± 0.020

90.081 ± 0.019

OM

9

0.021 ± 0.007

9

CM

9

0.079 ± 0.143

OM

9

CM

9

day 7

p valuevs day 0

day 1

day 7

p valuep value

0.636

0.505

0.727

0.341

0.083

0.273

n

Mean

SD

p value0.759

70.103 ± 0.015

0.906

0.175

9

0.078 ± 0.018

0.379

0.020 ± 0.005

0.464

7

0.036 ± 0.031

0.324

9

0.054 ± 0.101

0.717

9

0.036 ± 0.023

0.418

0.770 ± 0.862

90.798 ± 0.886

0.467

7

1.085 ± 1.037

0.305

0.405 ± 0.593

90.601 ± 0.770

0.046

9

0.698 ± 0.820

0.054

Paired t test was used for comparative analysis with Day 0. Student’s t test was used for between-group analysis. 3DG, 3-deoxyglucosone; GO, glyoxal;
MGO, methylglyoxal; OM, ostrich meat; CM, chicken meat; SD, standard deviation.

Table 7. Peripheral blood test.
Before and after analysis
Group

Before intake (day 0)
n

WBC

/μL

RBC

×10^4/μL

Hb

g/dL

Ht

%

MCV

fL

MCH

pg

MCHC

%

Plt

×10^5/μL

Mean

SD

day 1
n

Mean

Between-group analysis

vs day 0SD

day 7

p value

n

Mean

SD

vs day 0

day 1

day 7

p valuep valuep value

0.697

0.930

0.037

0.156

0.004

0.017

0.027

0.014

0.619

0.035

0.060

0.357

0.073

0.247

0.074

0.496

OM

9 6155.56 ± 1071.98

9 5455.56 ± 1393.72

0.025

7 5642.86 ± 2224.45

0.745

CM

9 6422.22 ± 1299.38

9 5900.00 ± 1139.20

0.197

9 6044.44 ± 1220.30

0.321

OM

9

465.44 ± 29.74

9458.00 ± 36.35

0.335

7

450.43 ± 25.04

0.568

CM

9

481.89 ± 35.83

9454.22 ± 35.42

0.001

9

465.67 ± 39.91

0.001

OM

9

14.27 ± 0.96

9

14.11 ± 1.12

0.415

7

13.77 ± 0.84

0.118

CM

9

14.98 ± 1.14

913.99 ± 1.12

0.000

9

14.23 ± 1.26

0.000

OM

9

43.27 ± 3.07

942.47 ± 2.86

0.218

7

42.93 ± 2.19

0.529

CM

9

44.91 ± 3.36

942.21 ± 2.89

0.001

9

43.39 ± 3.09

0.002

OM

9

92.78 ± 3.15

992.67 ± 2.58

0.849

7

95.43 ± 4.03

0.038

CM

9

93.33 ± 3.13

992.89 ± 2.96

0.225

9

93.22 ± 3.12

0.860

OM

9

30.66 ± 0.80

930.80 ± 0.64

0.429

7

30.57 ± 0.79

0.372

CM

9

31.08 ± 0.74

930.81 ± 0.83

0.037

9

30.57 ± 0.71

0.011

OM

9

32.99 ± 0.74

933.21 ± 0.64

0.139

7

32.07 ± 0.83

0.003

CM

9

33.37 ± 0.54

9

33.11 ± 0.71

0.257

9

32.77 ± 1.00

0.033

OM

9

29.59 ± 6.03

929.21 ± 5.58

0.521

7

32.03 ± 4.91

0.563

CM

9

28.91 ± 4.25

927.16 ± 4.72

0.005

9

28.87 ± 4.32

0.933

Paired t test was used for comparative analysis with Day 0. Student’s t test was used for between-group analysis. WBC, white blood cell; RBC, red blood
cell, Hb hemoglobin, Ht Hematocrit value; MCV, mean corpuscular volume; MCH, mean corpuscular hemoglobin; MCHC, mean corpuscular hemoglobin concentration: Plt, platelet count; OM, ostrich meat; CM, chicken meat; SD, standard deviation.

_ 57 _

Ostrich Meat Consumption and Plasma Amino Acids

a)

b)

RBC
OM

0
-5

- 0.2

-10

- 0.4

*

-25
-30

c)

-1.2

day 7

###
Before intake

d)

Ht
OM

1

day 1

day 7

MCV

2.5

CM

0.5

OM

*

1.5

- 0.5

CM

#

2

0

1

-1

*

- 1.5
-2

0.5
##

0
- 0.5

- 2.5
-3

###

-1

day 1

*

**

- 0.8

##
Before intake

CM

- 0.6
##

-20

OM

0

CM

-15

Hb

##
Before intake

day 1

-1

day 7

Before intake

day 1

day 7

Fig. 4. Changes of RBC profiles.
a) Red blood cell (RBC) count, b) Hemoglobin (Hb), c) Hematocrit (Ht), d) mean corpuscular volume. (MCV). Results

expressed as mean values. * p < 0.05, ** p < 0.01 vs CM, Student’s t test, n = 9, # p < 0.5, ## p < 0.01, ### p < 0.001 vs day 0 by
Paired t test. OM, ostrich meat; CM, chicken meat,

Peripheral blood tests showed decreases in RBC, Hb
and Ht in the CM intake group, which are considered to beiron-deficiency changes, but these were alleviated in OM( Fig. 4 ).
MCV significantly increased only in the OM intake
group on day 7 (Visit-6) compared to before intake (day 0,
Visit-4) with a significant difference between the groups.
MCHC significantly decreased on day 7 in both the OM and
CM intake groups, and this change is considered to be due
to iron deficiency. In the group that ingested OM potentiallywith high iron content, RBC, Hb, and Ht were maintained,
and it is assumed that the fluctuations in MCV also reflect
the homeostatic effect of OM intake. Additionally, the irondeficiency changes observed in the subjects' red blood cells
were due to blood sampling. Such fluctuations have been
observed in clinical trials in the past 6).
The discussion is necessary regarding the fact thatvitamin B12 was higher in CM than in OM. The subjects inthis study had a reduced blood volume due to blood sampling(although the condition cannot be called anemic), so they
consumed iron and vitamin B12 to maintain homeostasis,
activating blood-forming function.

It is speculated that B12 consumption increased in
the OM intake group because iron and vitamin B12 were
utilized for recovery. Whereas, in the CM intake group,iron supplementation was insufficient, hematopoiesis andhemoglobin synthesis were not as active, and vitamin B12
consumption was likely to be correspondingly low. As aresult, it is possible that the blood vitamin B12 concentrationin the CM intake group was higher than that in the OM
group. In order to maintain homeostasis of hematopoietic
function, it is desirable to ingest necessary components suchas iron, B12, and folic acid as food coexisting with proteinfrom the diet, before taking them as supplement ingredients.
Taurine is a sulfur-containing amino acid-like compoundthat exists in a free state in living organisms. In food, it isabundant in squid, octopus, shellfish, crustaceans, and fish(heart, spleen, and blood meat). The taurine content (mg/100g) of the main foods is oysters (1130), clams (1080), octopus(830), and squid (770). The taurine content of livestock meatis low, such as pork (22) and beef (30). The taurine content
of chicken meat varies depending on the part, including thighmeat (412), wing meat (97), and breast meat (29) 7).

_ 58 _Glycative Stress Research

Ostrich meat nutritional information
This survey revealed that ostrich meat (120) is richer intaurine than chicken breast meat, which can be said to be anoteworthy feature along with being rich in iron.
Comparing the nutritional content (per 100 g) of chicken
and ostrich meat, ostrich thigh meat (21.9 g protein, 1.8 g
fat, 104 kcal) and chicken breast (23.3 g protein, 1.9 g fat,
105 kcal) are similar. However, it should be noted that someparts of chicken are high in fat; thighs with skin-on (16.6 g
protein, 14.2 g fat, 190 kcal), and thighs without skin (23.3 g
protein, 5.0 g fat, 105 kcal) 8).
Chicken thighs are rich in taurine, but even without theskin, they have a rather high amount of fat. Chicken breastis a popular food among health-conscious people, and its
composition is high in protein and low in fat, similar to
ostrich meat, but ostrich meat is superior in terms of taurine
and iron supplementation. As a result of examining the lipid
composition of five different edible parts of the ostrich (leg,thigh, heart, gizzard, and liver), the thigh had the highest
PUFA/saturated fatty acids (SFA) and the highest n - 6/
n -3 ratio, showing the most favorable lipid quality index 9).
Ostrich thigh meat may have an advantage in this regard, so
we would like to compare it with other meats.

TaurineTaurine exists in almost all tissues in the living
body. The human body contains 0.1% of body weight oftaurine, and a person weighing 60 kg has approximately
60 g of taurine 10). of this, 60 -70 % is located in muscles,
where it plays an important role in muscle contraction andmaintenance of muscle function through C a 2+ mobilization,
osmotic pressure regulation, and antioxidant effects 11).
Taurine is a molecule (H2N-CH 2 -CH 2 -SO 3H) that plays
an important role in living organisms, and is synthesizedfrom sulfur-containing amino acids (methionine andcysteine). Since taurine does not have a carboxyl group, it is
not classified as an amino acid, and in principle does notconstitute a protein, and exists in a free state in the blood,tissue fluid, and cells of living organisms. Taurine is thesecond most concentrated amino acid in the brain after
glutamate. When taurine passes through biological membranes,
a transporter (taurine transporter: TauT ) is involved in theprocesses of gastrointestinal absorption 12), renal tubular
reabsorption 13, 14), and blood-retinal barrier passage 15). In
the liver, γ- amino butyric acid transporter 2 (GAT2) 16) is
involved.
Taurine can be derived from diet or synthesized within
the body (particularly in the liver). Dietary taurine is absorbed
from the gastrointestinal tract via TauT, transported to theliver via the portal vein, and taken up by hepatocytes via
GAT2 16). It is then supplied to tissues and cells throughout
the body via the hepatic vein. Some taurine is conjugatedwith bile in the liver, secreted into the intestinal tract, andexcreted in feces. Blood taurine is excreted into the renal
tubule via the renal glomerulus, and is reabsorbed dependingon taurine sufficiency.
Taurine also plays an important role in maintaining
homeostasis, which keeps the body and cells in a normal
state.
Since taurine suppresses lipid peroxidation, it isgenerally said to have antioxidant ability, but in reality it
is an aldehyde trapping effect by the -NH2 group. In theprocess of lipid peroxidation, fatty acids are oxidized dueto oxidative stress (excess of ROS and free radicals) andfatty acid-derived aldehydes are formed 17), causing glycationstress (excess of aldehydes). Many aldehydes are strong
electrophilic compounds and alkylate and modify biologicalmacromolecules such as nucleic acids and proteins 18).
Oxidative stress and glycative stress (including alkylationstress and carbonylation stress) should be appropriately
distinguished.
Various experimental results have shown that taurine
increases or preserves glutathione (GSH) 19), but this also
requires the perspective of glycative stress. By reducing
MGO, a typical biological aldehyde, by trapping, the loadon glyoxalase (an enzyme that metabolizes MGO, which
consumes GSH as a coenzyme) is reduced, and GSH isconserved. Reduction of intracellular aldehydes is thought
to prevent the accumulation of abnormal proteins such ascarbonylated proteins and advanced glycation end products(AGEs), thereby preventing an increase in ER stress.
Furthermore, cytoplasmic taurine is important as amolecule responsible for regulating osmotic pressure 20).
During high osmotic loads such as dehydration, taurine
moves into cells and protects the cells, and during low
osmotic loads such as water intoxication, taurine moves outof cells.
Taur ine modification of tR NA encoded by
mitochondrial DNA is essential for mitochondria to function
physiologically 21, 22). When taurine becomes insufficiently
modified due to lack of taurine or genetic mutations ( i.e.,
mitochondrial disease), normal protein synthesis is inhibited,
disrupting the electron transport chain and reducing energy
production.
Taurine has the effect of conjugating with bile acids,
reducing toxicity and regulating the affinity of bile acids
with the specific nuclear receptor FXR and G proteincoupled receptor TGR-5. It is involved in the regulation ofenergy metabolism in the body 23).
At the site of inflammation, it neutralizes the bactericidal
substance (hypochlorous acid) secreted by neutrophils andacts to control excessive inflammatory reactions 24).
Compared to reports on cultured cells and experimental
animals, there are fewer studies on taurine in humans.
An international epidemiological research study (WHOCARDIAC Study) conducted by Yamori and colleagues
for over 30 years, targeting approximately 20,000 people
in 25 countries around the world, has shown that dietarytaurine intake may be effective in preventing lifestyle-relateddiseases. Dietary taurine intake, as measured by urinary
taurine excretion, was found to be negatively correlatedwith ischemic heart disease mortality rate 25). Furthermore,
it has been shown that people who consume large amountsof taurine are more likely to have proper blood pressure andblood cholesterol levels, and less likely to be obese 26).

Ostrich evolution and skeletal muscle

The characteristics of ostrich meat are thought tohave been acquired through the process of evolution.
Flightless birds such as ostriches are called ratites (Ratitae).
South American snipe ostriches ( Tinamidae) can fly, and_ 59 _

Ostrich Meat Consumption and Plasma Amino Acids

together with ratites they form a taxonomic group called“Palaeognathae”. Ostriches, which are found in Africa,
were the first living Palaeognathae to separate from otherspecies. The most likely theory is that this divergence took
place more than 100 million years ago, when Palaeognathae
speciated in conjunction with the breakup of Gondwana, orthat it occurred 79 million years ago, based on research thatemphasizes DNA analysis 27).
Ratites is a general term for birds belonging to the order
Ostriformes, which includes the ostrich (Struthio camelus),rhea (Rhea americana), cassowary (Casuarius casuarius), emu(Dromaius novaehollandiae), moa (Dinornithidae), epiornis(Aepyornis), and kiwis (Apteryx mantelli). All of these species
are terrestrial, unable to fly, and, with the exception of thekiwis, are all large birds. It is thought that the reason ratites
cannot fly is not necessarily because they are primitive, but
because their wings and pectoral muscles have degenerated
as they adapted to life on the ground 1, 2).
Ostriches have evolved the ability to run, reaching
speeds of 70 km/h. It is possible to travel several kilometersat speeds of 50 to 60 km/h. The ostrich's running performance
depends on its well-developed buttocks and upper thighs, awell-balanced anatomical structure, and the characteristics
of powerful and durable muscles 4, 5). In particular, taurine
is an essential amino acid for the energy production in
mitochondria, so it seems to play an important role inexerting both muscle strength and endurance.

needed accumulates in the body. On the other hand, when the
body is deficient in taurine, the kidney tubules increase taurine
reabsorption to suppress urinary excretion and maintain theamount of taurine in the body. It was determined that there is
no problem with the safety of ostrich meat.

Conclusion
The ostrich's feed consists mainly of grass, which is noteaten by humans, and the production of ostrich meat is said
to have a low environmental impact. Among high-protein,low-fat avian meats, ostrich meat is richer in taurine and ironthan chicken breast, and has been shown to be useful as a safe
food ingredient. Among high-protein, low-fat avian meats,
ostrich meat is richer in taurine and iron than chicken breast,and has been shown to be useful as a safe food ingredient for
health-conscious consumers. Ingestion of the test foods (OM,
CM) increased the plasma total amino acid concentration,
which is expected to have an aldehyde trapping effect, andthe foods are also excellent in alleviating aldehyde sparks
that occur secondary to postprandial hyperglycemia.

Conflict of interest declaration
Ltd.

SafetyNo adverse events or side effects caused by the test
product were observed during the study period or after
the study was completed. Taurine is taken into cells via
transporters as necessary. Excess taurine is quickly excreted
from the kidneys into the urine, and no more taurine than isThis study was supported from Yoshinoya Holdings Co.,

Funding
No competitive research grants were obtained.

Reference
1) Morioka H. Japanese name classification of world birds.

1 - Ostrichformes - Scythidae. Japanese Journal ofOrnithology. 1980; 29: 99-102. (in Japanese)2) Udagawa T, Morioka H. Primary color new bird searchencyclopedia. Hokuryukan, Tokyo, 2003. (in Japanese)3) Ministry of Agriculture, Forestry and Fisheries (MAFF).
Do you know? Japan's food situation: Japan's food selfsufficiency rate, food self-sufficiency, and food security.
MAFF: Annual Report on Food, Agriculture and Rural
Areas in Japan FY 2016. (in Japanese)
https://www.maff.go.jp/j/pr/annual/attach/pdf/kokumin-2.
pdf4) Smith NC, Wilson AM, Jespers KJ, et al. Muscle
architecture and functional anatomy of the pelvic limb of
the ostrich (Struthio camelus). J Anat. 2006; 209: 765-779.
5) Rankin JW, Rubenson J, Hutchinson JR. Inferring muscle
functional roles of the ostrich pelvic limb during walking
and running using computer optimization. J R Soc Interface.
2016; 13: 20160035.

6) Ogura M, Takabe W, Yagi M, et al. Study for investigationof symptomatic improvement and safety of the ingestionof rooster comb degradation product containing lowmolecular hyaluronic acid (INJUV) in individuals withknee and lower back pain; open-label trial with no control
group. Glycative Stress Res. 2018; 5: 55-67.
7) Kondo K, Nakajima J. Taurine contents in the meats.
Research Reports of Nagano Prefecture General Industrial
Technology Center. 2007; 2: F27-F28. (in Japanese)8) Ministry of Education, Culture, Sports, Science andTechnology (MEXT). Standard tables of food compositionin Japan-2020 (8th edition). MEXT. Office for Resources
Policy Division, Science and Technology Policy Bureau.
2020. (in Japanese)
https://www.mext.go.jp/a_menu/syokuhinseibun/mext_
01110.html
9) Antunes IC, Ribeiro MF, Pimentel FB, et al. Lipid profileand quality indices of ostrich meat and giblets. Poult Sci.
2018; 97: 1073-1081.

_ 60 _Glycative Stress Research10) Akanuma S, Kubo Y, Hosoya K. The pharmacokinetics oftaurine and the role played by transporters in its dynamics.
Taurine Research. 2015; 1: 44-46. (in Japanese)
11) Spriet LL, Whitfield J. Taurine and skeletal muscle
function. Curr Opin Clin Nutr Metab Care. 2015; 18: 96101.
12) Tochitani S. Taurine: A maternally derived nutrient
linking mother and offspring. Metabolites. 2022; 12: 228.
13) Han X, Patters AB, Jones DP, et al. The taurine
transporter: mechanisms of regulation. Acta Physiol (Oxf).
2006; 187: 61-73.
14) Chesney RW, Han X, Patters AB. Taurine and the renal
system. J Biomed Sci. 2010; 17 Suppl 1: S4.
15) Ito T, Miyazaki N, Schaffer S, et al. Potential anti-aging
role of taurine via proper protein folding: A study fromtaurine transporter knockout mouse. Adv Exp Med Biol.
2015; 803: 481- 487.
16) Ikeda S, Tachikawa M, Akanuma S, et al. Involvement of
γ-aminobutyric acid transporter 2 in the hepatic uptake of
taurine in rats. Am J Physiol Gastrointest Liver Physiol.
2012; 303: G291-G297.
17) Sato K, Zheng Y, Martin-Morales A, et al. Generation ofshort chain aldehydes and glyceraldehyde 3-phosphate
dehydrogenase (GAPDH). Glycative Stress Res. 2022; 9:129-134.
18) Uchida K. Formation of acrolein and its conjugate withproteins during lipid peroxidation. Journal of Japan Oil
Chemists' Society. 1988; 47: 1207-1215. (in Japanese)
19) Baliou S, Adamaki M, Ioannou P, et al. Protective role oftaurine against oxidative stress (Review). Mol Med Rep.
2021; 24: 605.
20) Burg MB. Molecular basis of osmotic regulation. Am J
Physiol. 1995; 268: F983-F996.
21) Schaffer SW, Jong CJ, Warner D, et al. Taurine deficiency
and MELAS are closely related syndromes. Adv Exp Med
Biol. 2013; 776: 153-165.
22) Miyazaki T, Sasaki SI, Toyoda A, et al. Impaired bile
acid metabolism with defectives of mitochondrial-tRNA
taurine modification and bile acid taurine conjugation in
the taurine depleted cats. Sci Rep. 2020; 10: 4915.
23) Sharma R, Long A, Gilmer JF. Advances in bile acidmedicinal chemistry. Curr Med Chem. 2011; 18: 40294 052.
24) Marcinkiewicz J, Kontny E. Taurine and inflammatory
diseases. Amino Acids. 2014; 46: 7-20.
25) Yamori Y, Nara Y, Ikeda K, et al. Is taurine a preventive
nutritional factor of cardiovascular diseases or just a
biological marker of nutrition? Adv Exp Med Biol. 1996;
403: 623-629.
26) Sagara M, Murakami S, Mizushima S, et al. Taurine in
24-h urine samples is inversely related to cardiovascularrisks of middle aged subjects in 50 populations of theworld. Adv Exp Med Biol. 2015; 803: 623-636.
27) Yonezawa T, Segawa T, Mori H, et al. Phylogenomics andmorphology of extinct paleognaths reveal the origin andevolution of the ratites. Curr Biol. 2017; 27: 68-77.

_ 61 _