The Effect Of Supplementing A Rice Diet With Lysine, Methionine, And Threonine On The Digestibility Coefficient, Biological Value, And Net Protein Utilization Of The Proteins And On The Retention Of Nitrogen In Children


Parthasarathy, H.N.; Joseph, K.; Daniel, V.A.; Doraiswamy, T.R.; Sankaran, A.N.; Rao, M.N.; Swaminathan, M.; Sreenivasan, A.; Subrahmanyan, V.

Canadian Journal of Biochemistry 42: 385-393

1964


The effect of supplementing a rice diet providing about 1.3[long dash]1.4 g protein/kg body weight with lysine, methionine, and threonine individually or together on true digestibility coefficient (DC), biological value (BV), and net protein utilization (NPU) of the proteins was studied in girls aged 8[long dash]9 years. The retention of N on the rice diet was very low (9.5% of intake in the first series and 8.5% in the second series). The BV and NPU of the proteins of rice diet were 64.1 and 52.9 in the first series and 66.6 and 54.9 in the second series. Supplementation of the rice diet with lysine or methionine or lysine + methionine brought about a significant improvement in N retention (12.6, 12.0, 13.5% of intake) and in the BV (68.3, 66.3, 69.3) and NPU (54.8, 55.7, 55.8). When the rice diet was supplemented with lysine and threonine, a highly significant improvement in the N retention (18.9% of intake) and in the BV (77.4) and NPU (63.4) was observed. Addition of methionine to rice diet containing lysine and threonine resulted in a further improvement in N retention, BV and NPU of the diets. The net available protein (g/kg body weight) from the different diets were as follows: rice diet, 0.71; rice diet + lysine, 0.76; rice diet + methionine, 0.74; rice + lysine + methionine, 0.77; rice + lysine + threonine, 0.85; rice diet + lysine + threonine + methionine, 0.91; and skim milk powder diet, 0.96-0.98.

THE
EFFECT
OF
SUPPLEMENTING
A
RICE
DIET
WITH
LYSINE,
METHIONINE,
AND
THREONINE
ON
THE
DIGESTIBILITY
COEFFICIENT,
BIOLOGICAL
VALUE,
AND
NET
PROTEIN
UTILIZATION
OF
THE
PROTEINS
AND
ON
THE
RETENTION
OF
NITROGEN
IN
CHILDREN
H.
N.
PARTHASARATHY,
KANTHA
JOSEPH,
V.
A.
DANIEL,
T.
R.
DORAISWANIY,
A.
N.
SANKARAN,
M.
NARAYANA
RAO,
M.
SWAMINATHAN,
A.
SREENIVASAN,
AND
V.
SUBRAHMANYAN
Central
Food
Technological
Research
Institute,
Mysore,
India
Received
September
10,
1963
Abstract
The
effect
of
supplementing
a
rice
diet
providing
about
1.3-1.4
g
protein
per
kg
body
weight
with
lysine,
methionine,
and
threonine
individually
or
together
on
true
digestibility
coefficient
(DC),
biological
value
(BV),
and
net
protein
utiliza-
tion
(NPU)
of
the
proteins
has
been
studied
in
girls
aged
8-9
years.
The
retention
of
nitrogen
on
the
rice
diet
was
very
low
(9.5%
of
intake
in
the
first
series
and
8.5%
in
the
second
series).
The
BV
and
NPU
of
the
proteins
of
rice
diet
were
64.1
and
52.9
in
the
first
series
and
66.6
and
54.9
in
the
second
series.
Supplementation
of
the
rice
diet
with
lysine
or
methionine
or
lysine
methionine
brought
about
a
significant
improvement
in
N
retention
(12.6,
12.0,
13.5%
of
intake)
and
in
the
BV
(68.3,
66.3,
69.3)
and
NPU
(54.8,
55.7,
55.8).
When
the
rice
diet
was
supple-
mented
with
lysine
and
threonine,
a
highly
significant
improvement
in
the
N
retention
(18.9%
of
intake)
and
in
the
BV
(77.4)
and
NPU
(63.4)
was
observed.
Addition
of
methionine
to
rice
diet
containing
lysine
and
threonine
resulted
in
a
further
improvement
in
N
retention,
BV,
and
NPU
of
the
diets.
The
net
available
protein
(g/kg
body
weight)
from
the
different
diets
were
as
follows:
rice
diet,
0.71;
rice
diet
lysine,
0.76;
rice
diet
methionine,
0.74;
rice
diet
lysine
methionine,
0.77;
rice
diet
lysine
threonine,
0.85;
rice
diet
+
lysine
threonine
methionine,
0.91;
and
skim
milk
powder
diet,
0.96-0.98.
Introduction
The
nutritional
improvement
of
rice
proteins
by
amino
acid
fortification
has
been
the
subject
of
investigation
by
a
number
of
workers
(1-4).
Supplementa-
tion
of
rice
proteins
with
lysine
and
threonine
improved
to
a
significant
extent
the
biological
value
and
protein
efficiency
ratio
for
the
growing
rat
(1,
2).
Neither
lysine
nor
threonine
alone was
effective,
while
both
together
increased
growth
rates
approximately
threefold.
In
the
above
studies
no
beneficial
effect
was
observed
when
methionine
was
added
to
rice
diet
fortified
with
lysine
and
threonine.
Sure
(3),
however,
found
an
increase
in
the
protein
efficiency
ratio
of
rice
proteins
when
methionine
was
added
in
addition
to
lysine
and
threonine.
In
the
present
investigation,
the
effect
of
supplementing
a
rice
diet
with
lysine,
threonine,
and
methionine
individually
or
together
on
the
digestibility
co-
efficient
(DC),
biological
value
(BV),
and
net
protein
utilization
(NPU)
of
the
proteins
has
been
studied
in
children.
Experimental
The
metabolism
studies
were
carried
out
in
two
series.
The
first
series
related
to
studies
on
the
effect
of
addition
of
lysine
and
methionine
individually
or
Canadian
Journal
of
Biochemistry.
Volume
42
(1964)
385
386
CANADIAN
JOURNAL
OF
BIOCHEMISTRY.
VOL.
42,
1964
together
to
a
rice
diet
on
the
N
retention
and
NPU
of
the
diets
while
the
second
series
related
to
the
effect
of
addition
of
lysine
and
threonine
or
lysine,
threo-
nine,
and
methionine.
Subjects
The
subjects
of
the
study
were
girls
of
age
group
8-9
years
who
were
resi-
dents
of
a
local
boarding
home
in
Mysore
city.
The
first
series
of
studies
was
carried
out
with
six
girls
and
the
second
with
eight
girls.
The
ages,
heights,
and
weights
of
the
girls
are
given
in
Table
I.
All
of
them
belonged
to
the
low-
income
groups
and
were
subsisting
on
a
rice
diet
similar
to
the
one
used
in
this
experiment.
They
were
examined
clinically
and
found
free
from
diseases
likely
to
interfere
with
the
experiment.
TABLE
I
Ages,
heights,
and
weights
of
children
at
the
beginning
of
the
test
Series
I
Series
II
Girl
No.
Age
(years)
Height
(cm)
Weight
(kg)
Girl
No.
Age
(years)
Height
(cm)
Weight
(kg)
1
9
129.5
23.2
7
9
129.5
20.4
2
9
125.1
19.2
8
9
129.5
20.7
3
S
114.9
18.1
9
S
127.0
18.9
4
S
112.4
17.6
10
9
125.4
20.3
5
S
109.8
16.5
11
9
124.5
20.7
6 9
118.1
20.3
12
8
124.5
18.2
13
9
121.9
19.2
14
8
121.3
18.2
Experimental
Diets
and
Feeding
of
the
Children
The
rice
diet
used
in
the
present
investigation
was
similar
to
that
consumed
habitually
by
the
children
in
the
boarding
home.
It
consisted
mainly
of
rice
and
contained
small
amounts
of
legumes,
vegetables,
oil,
and
skim
milk
powder
and
provided
1580
kcal/day.
The
composition
of
the
experimental
diets
is
given
in
Table
II.
The
subjects
were
fed
three
times
a
day.
The
pattern
of
breakfast,
lunch,
and
dinner
was
similar
to
that
described
by
Reddy
et
al.
(5).
The
amino
acid
supplements
were
incorporated
in
rice
pudding
and
given
in
three
equal
doses
along
with
breakfast,
lunch,
and
dinner.
The
quantities
of
different
amino
acid
supplements
administered
to
each
subject
are
given
in
Table
II.
Methionine,
lysine,
and
threonine
were
added
in
amounts
to
bring
the
S-amino
acid
content
of
the
fortified
diet
to
a
level
present
in
FAO
reference
protein,
and
lysine
and
threonine
to
levels
present
in
milk
protein.
The
essential
amino
acid
content
of
the
different
diets,
determined
according
to
Krishna-
murthy
et
al.
(6),
is
given
in
Table
III.
The
intakes
of
essential
amino
acids
(mg/kg
body
weight)
from
the
different
diets,
as
compared
with
their
amino
acid
requirements,
are
given
in
Table
IV.
The
procedure
adopted
for
the
feeding
of
children
and
for
the
collection
of
PARTHASARATHY
ET
AL.:
PROTEIN
UTILIZATION
387
TABLE
II
Mean
daily
intake
(g)
of
foodstuffs
by
the
children
on
different
diets*f
Foodstuffs
Rice
dietI
Skim
milk
powder
Rice,
raw
milled
250.0
-
Sugar
45.0 45.0
Peanut
oil
(fortified
with
vitamins
A
and
D)
45.0
45.0
Salt
mixture§
5.0
5.0
Vitaminized
starch
5.0
5.0
Tur
dhal
(cajanus
cajan)
12.4
-
Condiments
8.0
-
Tapioca
flour
(washed
with
dilute
alkali)
-
125.0
Corn
starch
-
80.0
Skim
milk
powder
5.0
70.0
*All
the
diets
supplied
in
addition
(g/day):
common
salt,
12.0;
tamarind
fruit
pulp,
8.0;
non-leafy
vegetables
(knol
khol,
brinjals,
ladies
finger,
and
radish
white),
60.0;
onions,
20.0.
tEach
child
received
in
addition
50
mg
of
ascorbic
acid
daily
in
the
form
of
a
sweetened
drink.
IIn
the
I
series,
each
child
in
addition
received
316
mg
dl-methionine
during
the
2nd
period;
1128
mg
/-lysine
HC1
during
3rd
period;
and
316
mg
dl-methionine
and
1128
mg
1-lysine
IIC1
during
the
4th
period.
In
the
II
series,
each
child
in
addition
received
1128
mg
/-lysine
HC1
and
452
mg
dl-threonine
during
the
second
period;
and
1128
mg
1-lysine
HC1,
452
mg
dl-
threonine,
and
316
mg
dl-methionine
during
the
3rd
period.
§Osborne
and
Mendel
salt
mixture.
11Provided
the
daily
requirement
of
B
vitamins
as
recommended
by
the
(U.S.A.)
National
Research
Council,
Food
and
Nutrition
Board
(1958).
TABLE
III
Essential
amino
acid
content
(g/16
g
N)
of
the
mixed
proteins
of
the
different
diets
Amino
acids
Diets
FAO
reference
(1957)
protein
pattern
Ideal
reference
protein
pattern
A*
G
Arginine
5.75
3.86
6.6
Histidine
2.08
2.55
2.4
Lysine
4.49
7.45
4.2
7.5
Leucine
8.37
9.74
4.8
10.0
Isoleucine
4.81
6.25
4.2
6.6
Methionine
1.71
2.40
2.2
2.8
Cystine
1.26
0.94
-
2.0
Total
sulphur
amino
acids
2.97
3.33
4.2
4.8
Phenylalanine
5.26 4.87
2.8
5.8
Threonine
3.82
4.53
2.8
5.0
Tryptophan
1.08
1.39
1.4
1.6
Valine
6.47
6.93
4.2
7.0
Protein
scoref
FAO
pattern
71
79
100
-
Ideal
reference
protein
60
69
100
*The
essential
amino
acid
contents
(g/16
g
N)
of
the
diets
B,
C,
D,
E,
and
F
were
the
same
as
those
of
diet
A
except
in
the
following
respects.
Diet
B:
methionine,
2.94;
total
sulphur
amino
acids,
4.20.
Diet
C:
lysine,
8.0.
Diet
D:
lysine,
8.0;
methionine,
2.94;
and
total
sulphur
amino
acids,
4.20.
Diet
E:
lysine,
8.0;
and
threonine,
4.70.
Diet
F:
lysine,
8.0;
threonine,
4.70;
methionine,
2.94;
and
total
sulphur
amino
acids,
4.20.
tProtein
scores
of
diets
according
to
FAO
and
Ideal
protein
pattern
were
as
follows:
B,
77
and
60;
C,
71
and
62;
D,
71
and
62;
E,
77
and
67;
F,
77
and
67.
388
CANADIAN
JOURNAL
OF
BIOCHEMISTRY.
VOL.
42,
1964
TABLE
IV
Mean
daily
intake*
(mg/kg)
of
essential
amino
acids
by
the
children
from
the
different
diets
as
compared
with
the
amino
acid
requirements
Amino
acids
Basal
low-protein
diet
Diets
Amino
acid
requirementst
(mg/kg)
A
(rice
diet)
G
(low-protein
diet
+
skim
milk
powder)
Arginine
7.3
77.1
53.6
Histidine
2.1
27.6
35.4
Lysine
4.7
59.9
103.1
60.0
Leucine
10.9
111.9 134.9
45.0
Isoleucine
5.7
64.6
87.0
30.0
Methionine
2.1
22.9
33.3
27.0
Cystine
1.6
16.7
13.0
-
Total
sulphur
amino
acids
3.7
39.6
46.3
27.0
Phenvlalanine
6.3
70.3
67.7
27.0
Threonine
4.7
51.0
63.0
35.0
Tryptophan
1.6
14.5
19.3
9.0
Valine
8.9
86.5
95.8
33.0
*The
mean
daily
intakes
of
essential
amino
acids
by
the
children
from
diets
B,
C,
D,
E,
and
F
were
nearly
the
same
as
diet
A,
except
in
the
following
respects.
Diet
B:
methionine,
39.1;
total
sulphur
amino
acids,
55.8.
Diet
C:
lysine,
109.9.
Diet
D:
methionine,
40.1;
total
sulphur
amino
acids,
57.3;
and
lysine,
109.3.
Diet
E:
lysine,
107.6;
and
threonine,
63.3.
Diet
F:
lysine,
108.6;
methionine,
39.8;
total
sulphur
amino
acids,
57.2;
and
threonine,
63.8.
tData
of
Nakagawa
et
al.
(13-16).
excreta
was
similar
to
that
of
Tasker
et
al.
(7).
The
composition
of
the
low-
protein
diet
was
similar
to
the
one
used
by
Parthasarathy
et
al.
(8).
The
first
series
of
experiments
consisted
of
six
periods:
period
1,
rice
diet;
period
2,
rice
diet
±
methionine;
period
3,
rice
diet
±
lysine;
period
4,
rice
diet
±
lysine
methionine;
period
5,
low-protein
diet
±
skim
milk
powder;
and
period
6,
low-protein
diet.
The
second
series
consisted
of
five
periods:
period
1,
rice
diet;
period
2,
rice
diet
±
lysine
threonine;
period
3,
rice
diet
+
lysine
threonine
methionine;
period
4,
low-protein
diet
+
skim
milk
powder;
and
period
5,
low-protein
diet.
Each
period
was
of
10
days
duration.
The
first
5
days
were
considered
as
a
preliminary
period,
the
faeces
and
urine
being
collected
during
the
last
5
days.
Since
the
experimental
periods
were
of
short
duration,
the
design
adopted
was
not
likely
to
affect
the
interpretation
of
results.
A
similar
procedure
was
followed
by
Scrimshaw
et
al.
(9)
in
their
studies
on
the
effect
of
amino
acid
supplementation
of
a
maize
diet
on
nitrogen
reten-
tion
in
children.
The
nitrogen
in
the
diet,
urine,
and
faeces
was
determined
by
the
micro-Kjeldahl
method.
The
digestibility
coefficient
and
biological
value
of
the
proteins
of
the
diets
were
calculated
according
to
Tasker
et
al.
(7).
The
net
protein
utilization
(operative)
(NPU
(00
)
was
calculated
according
to
Platt,
Miller,
and
Payne
(10)
by
using
the
following
formula:
NPU
(00
=
(true
digestibility
coefficient
X
biological
value)
÷
100.
PARTHASARATHY
ET
AL.:
PROTEIN
UTILIZATION
389
Statistical
Treatment
of
Data
The
data
were
analyzed
by
the
analysis
of
variance
method
appropriate
for
randomized
block
design,
considering
each
subject
as
a
block,
and
differences
were
tested
for
significance
by
using
a
one-sided
or
two-sided
t
test,
whichever
is
appropriate.
Results
Data
regarding
the
endogenous
urinary
and
faecal
N
are
given
in
Table
V
and
those
of
digestibility
coefficient,
biological
value,
and
net
protein
utiliza-
tion
in
Table
VI.
The
net
available
protein
in
children
on
the
different
diets
is
given
in
Table
VII.
TABLE
V
Daily
urinary
and
faecal
excretion
(g)
of
nitrogen
by
the
children
on
low-protein
diet
Series
I
Series
II
Girl
No.
Urinary
Faecal
Total
Girl
No.
Urinary
Faecal
Total
1
1.28
0.84
2.12
7
1.16
0.89
2.05
2
1.01
0.73
1.74
8
1.22
0.73
1.95
3
0.95
0.75
1.70
9
1.10
0.83
1.93
4
0.90
0.79
1.69
10
1.03
0.89
1.92
5
0.S5
0.72
1.57
11
1.11
0.75
1.86
6
1.11
0.77
1.88
12
1.1.0
0.72
1.82
13
1.05
0.72
1.77
14
1.03
0.69
1.72
Mean
value
1.01*
0.77*
1.78*
1.10t
0.78t
1.881
±0.103
±0.076
±0.079
±0.023
±0.028
±0.038
*Mean
value
with
its
standard
error
(5
d.f.).
tMean
value
with
its
standard
error
(7
d.f.).
Essential
Amino
Acid
Intake
and
Requirements
(Tables
III
and
IV)
The
rice
diet
provided
daily
25.7
g
protein
(N
X
6.25);
of
this
rice,
red
gram
dhal,
and
skim
milk
powder
contributed
17.5,
3.1,
and
1.75
g
protein
respec-
tively.
The
proteins
of
the
rice
diet
contained
(g/16
g
N)
lysine,
4.49;
total
sulphur
amino
acids,
2.97;
and
threonine,
3.82;
while
rice
protein
contained
(g/16
g
N)
lysine,
3.77;
total
sulphur
amino
acids,
3.05;
and
threonine,
3.75.
The
data
show
that
the
lysine
content
of
the
rice
diet
proteins
was
slightly
higher
while
threonine
and
total
S-amino
acid
contents
were
nearly
the
same
as
those
of
rice
proteins.
The
protein
scores
of
the
different
diets
as
compared
with
FAO
reference
protein
pattern
(11)
and
Ideal
reference
protein
pattern
(12)
suggested
by
one
of
us,
calculated
according
to
the
method
of
FAO
Committee,
are
as
follows:
rice
diet,
71
and
60;
rice
diet
supplemented
with
lysine,
threonine,
and
methio-
nine,
77
and
67;
and
milk
diet,
79
and
69.
Data
regarding
the
essential
amino
acid
intake
and
requirements
of
the
children
are
given
in
Table
IV.
It
is
evident
that
the
rice
diet
at
a
level
of
1.3
g
TABLE
VI
Mean
daily
balance
of
nitrogen
and
digestibility
coefficient,
biological
value,
and
net
protein
utilization
of
the
proteins
of
rice
diet
supplemented
with
amino
acids,
/-lysine,
d/-methionine,
and
dl-threonine
Intake
Excretion
(g)
Balance
Apparent
digesti-
bility
(%)
True
digesti-
bility
(%)
Biological
value
NPU
(
,,,,
)
Diets*
g
mg/kg
Urinary
Faecal
Total
g
mg/kg
7,
0
intake
Series
I
Rice
diet
4.11
215
2.27
1.45
3.72
0.39
20.6
9.5
64.8
82.6
64.1
52.9
Rice
diet
+
methionine
4.08
213
2.21
1.38
3.59
0.49
25.9
12.0
66.1
84.0
66.3
55.7
Rice
diet
+
lysine
4.22
220
2.13
1.56
3.69
0.53
27.9
12.6
62.9
80.4
68.3
54.8
Rice
diet
+
lysine
+
methionine
4.21
220
2.09
1.55
3.64
0.57
30.1
13.5
63.2
80.6
69.3
55.8
Skim
milk
powder
4.26
223
1.73
1.35
3.08
1.18
62.3
27.8
68.4
85.7
81.3
69.7
Standard
error
of
the
mean
(20
d.f.)
±0.03
±1.73
±0.81
±0.98
±1.00
±0.67
±0.82
Series
II
Rice
diet
4.05
207
2.22
1.49
3.71
0.34
17.6
8.5
63.3
82.5
66.6
54.9
Rice
diet
+
lysine
+
threonine
4.22
215
1.88
1.54
3.42
0.80
40.8
18.9
63.5
82.0
77.4
63.4
Rice
diet
+
lysine
+
threonine
+
methionine
4.26
217
1.72
1.56
3.28
0.98
50.1
23.0
63.5
81.7
82.1
67.1
Skim
milk
powder
4.28
218
1.70
1.38
3.08
1.20
61.3
28.0
67.7
85.9
83.7
71.8
Standard
error
of
the
mean
(20
d.f.)
±0.03
±1.58
±0.70
±0.73 ±0.73
±0.70
±0.70
*Calorie
intake
1580
kcal.
ca
C
ANAD
IAN
JO
UR
NAL
OF
B
IOCH
E
MIS
TRY
.
VOL
.
42
,
19
64
PARTHASARATHY
ET
AL.:
PROTEIN
UTILIZATION
391
TABLE
VII
Mean
protein
intake
and
net
available
protein
in
children
on
different
diets
FAO
reference
protein
Ideal
protein
requirements
requirements$
Net
available
(g/kg) (g/kg)
Protein
intake
protein*
Diets
g
g/kg
g
g/kg
Mini-
mum
Opti-
mum
Mini-
mum
Opti-
mum
Series
I
Rice
diet
25.7
1.3
13.6
0.71
Rice
diet
methionine
25.5
1.3
14.2
0.74
Rice
diet
+
lysine
26.4
1.4
14.5
0.76
Rice
diet
methionine
lysine
26.3
1.4
14.7
0.77
Skim
milk
powder
26.6
1.4
18.5
0.96
0.6
0.90
0.64
0.96
Series
II
Rice
diet
25.3
1.3
13.9
0.71
Rice
diet
+
lysine
threonine
26.4
1.3
16.7
0.85
Rice
diet
+
lysine
threonine
methionine
26.6
1.4
17.8
0.91
Skim
milk
powder
26.8
1.4
19.2
0.98
*(Protein
intake
X
NPU)
±
100.
tFAO
report
No.
16;
FAO,
Rome.
1957.
M.
Swaminathan.
Indian
J.
Pediat.
30,
189
(1963).
protein/kg
body
weight
met
all
the
essential
amino
acid
requirements
of
children
as
assessed
by
Nakagawa
et
al.
(13-16).
Nitrogen
Retention
Nitrogen
retention
on
the
rice
diet
was
only
9%
of
the
intake.
Supplementa-
tion
of
the
rice
diet
with
lysine
and
methionine
individually
or
together
resulted
in
a
significant
increase
in
the
retention
of
nitrogen
(P
<
0.01,
P
<
0.05,
and
P
<
0.01
respectively).
However,
supplementation
of
the
diet
with
lysine
and
threonine
significantly
(P
<
0.001)
increased
the
nitrogen
retention
(18.9%
of
intake).
Addition
of
methionine
to
the
above
diet
resulted
in
a
further
significant
improvement
(P
<
0.001)
in
nitrogen
retention
(23.0%
of
the
in-
take)
,
comparing
well
with
that
(28.0%)
obtained
on
a
milk
protein
diet.
True
Digestibility
Coefficient
The
true
digestibility
coefficient
of
the
proteins
of
the
rice
diet
and
the
amino
acid
supplemented
rice
diets
ranged
from
80.4
to
84.0,
there
being
no
significant
difference
between
the
values.
Biological
Value
The
biological
value
(BV)
of
the
proteins
in
the
rice
diet
was
64.1
in
the
first
series
and
66.6
in
the
second
series.
Supplementation
of
the
diet
with
lysine
and
methionine,
individually
or
together,
resulted
only
in
a
slight
increase
in
the
392
CANADIAN
JOURNAL OF
BIOCHEMISTRY.
VOL.
42,
1964
BV
of
the
proteins,
the
increases
being
statistically
significant
(P
<
0.001,
P
<
0.05,
and
P
<
0.001
respectively).
However,
supplementation
of
the
rice
diet
with
lysine
and
threonine
resulted
in
a
highly
significant
increase
(P
<
0.001)
in
the
BV
of
the
proteins
to
77.4.
Addition
of
methionine
to
the
above
diet
caused
a
further
significant
increase
(P
<
0.001)
in
the
BV
of
the
proteins
to
82.1,
compared
with
a
value
of
83.7
obtained
for
milk
protein.
Net
Protein
Utilization
The
net
protein
utilization
of
the
proteins
of
the
rice
diet
was
52.9
in
the
first
series
and
54.9
in
the
second
series.
There
is
a
slight
increase
in
the
NPU
of
the
rice
diet
supplemented
with
lysine
and
(or)
methionine,
the
increases
with
methionine
or
methionine
and
lysine
supplementation
being
significant
at
P
<
0.05.
Supplementation
of
the
rice
diet
with
lysine
and
threonine
brought
about
a
highly
significant
increase
(P
<
0.001)
in
the
NPU
of
the
rice
diet
to
63.4.
Addition
of
methionine
to
the
above
diet
resulted
in
a
further
significant
increase
(P
<
0.001)
in
the
NPU
of
the
diet
to
67.1,
as
compared
to
NPU
of
71
on
milk
protein
diet.
Net
Available
Protein
The
protein
intake
ranged
from
1.29
to
1.39
g/kg
body
weight
on
the
dif-
ferent
diets.
The
net
available
protein
(g/kg
body
weight)
was
as
follows:
rice
diet,
0.71;
rice
diet
supplemented
with
lysine
and
(or)
methionine,
0.74-0.77g;
rice
diet
supplemented
with
lysine
and
threonine,
0.85;
rice
diet
supplemented
with
lysine,
threonine,
and
methionine,
0.91;
and
milk
diet,
0.98.
Discussion
The
rice
diet,
at
a
level
of
1.3
g
protein/kg
body
weight,
met
all
the
essential
amino
acid
requirements
of
children
as
assessed
by
Nakagawa
et
al.
(13-16).
It
is,
however,
to
be
pointed
out
here,
that
Nakagawa
et
al.
(13-16)
in
their
studies
on
the
assessment
of
amino
acid
requirements
in
children
have
used
pure
amino
acids
which
are
absorbed
completely.
The
extent
of
digestibility
of
the
proteins
and
availability
of
amino
acids
in
the
diet
is
a
factor
which
has
to
be
taken
into
consideration
in
determining
the
adequacy
of
the
diet
to
meet
the
amino
acid
requirements.
When
the
digestibility
coefficient
is
taken
into
consideration,
the
rice
diet
becomes
limiting
in
lysine.
The
results
obtained
in
the
present
investigation
have
shown
that
supple-
mentation
of
a
rice
diet
(providing
about
1.3-1.4
g
protein
per
kg
body
weight)
with
a
mixture
of
lysine
and
threonine
or
lysine,
threonine,
and
methionine
brought
about
a
highly
significant
increase
in
N
retention,
biological
value,
and
NPU
of
the
proteins.
The
net
available
protein
(g/kg
body
weight)
from
the
rice
diet
(0.71)
was
equal
to
the
minimal
protein
requirements
of
FAO
reference
protein
(0.6)
or
Ideal
reference
protein
(0.64),
while
that
from
the
rice
diet
supplemented
with
lysine,
threonine,
and
methionine
(0.91)
and
milk
diet
(0.98)
was
nearly
equal
to
that
of
the
optimal
requirements
(0.90-0.96)
of
these
proteins.
PARTHASARATHY
ET
AL.:
PROTEIN
UTILIZATION
393
The
present
study
has
shown
that
the
primary
limiting
amino
acids
in
the
rice
diet
are
lysine
and
threonine,
and
the
secondary
deficiency
is
methionine.
These
results
are
in
conformity
with
those
reported
by
Sure
(3)
in
experiments
with
albino
rats.
From
the
amino
acid
composition,
one
would
expect
improve-
ment
in
the
quality
of
rice
protein
by
the
addition
of
lysine
alone,
as
has
been
reported
in
the
case
of
wheat
proteins
(17,
18).
Since
the
nutritive
value
of
rice
proteins
for
albino
rats
can
be
improved
only
by
the
addition
of
both
lysine
and
threonine,
Flodin
(19)
suggested
that
about
40%
of
the
threonine
present
in
rice
protein
is
not
available
for
growth
and
both
lysine
and
threonine
are
equally
limiting.
Further
work
on
the
availability
of
threonine
present
in
rice
proteins
is
therefore
indicated.
References
1.
L.
J.
PECORA
and
J.
M.
HUNDLEY.
J.
Nutr.
44,
101
(1951).
2.
A.
E.
HARPER,
M.
E.
WINJE,
D.
A.
BENTON,
and
C.
A.
ELVEHJEM.
J.
Nutr.
56,
187
(1955).
3.
B.
SURE.
J.
Am.
Dietet.
Assoc.
31,
1232
(1955).
4.
M.
C.
KIK.
J.
Am.
Dietet.
Assoc.
32,
647
(1956).
5.
S.
K.
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T.
R.
DORAISWAMY,
A.
N.
SANKARAN,
M.
SWAMINATHAN,
and
V.
SUBRAH-
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Brit.
J.
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8,
17
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K.
KRISHNAMURTHY,
P.
K.
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T.
N.
RAMAKRISHNAN,
R.
RAJAGOPALAN,
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Exptl.
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73
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P.
K.
TASKER,
T.
R.
DORAISWAMY,
M.
NARAYANA
RAO,
M.
SWAMINATHAN,
A.
SREENIVA-
SAN,
and
V.
SUBRAHMANYAN.
Brit.
J.
Nutr.
16,
361
(1962).
8.
H.
N.
PARTHASARATHY,
T.
R.
DORAISWAMY,
MYNA
PANEMANGALORE,
M.
NARAYANA
RAO,
B.
S.
CHANDRASEKHAR,
M.
SWAMINATHAN,
A.
SREENIVASAN,
and
V.
SUBRAHMANYAN.
Can.
J.
Biochem.
This
issue.
9.
N.
S.
SCRIMSHAW,
R.
BRESSANI,
M.
BEHAR,
and
F.
VITERI.
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Nutr.
66,
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10.
B.
S.
PLATT,
D.
S.
MILLER,
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P.
R.
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to
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J.
F.
Brock
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J.
and
A.
Churchill
Ltd.,
London.
1961.
11.
FAO.
Nutr.
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16.
Protein
requirements.
Food
Agr.
Organ.
U.N.,
Rome.
1957.
12.
M.
SWAMINATHAN.
Indian
J.
Pediat.
30,
189
(1963).
13.
I.
NAKAGAWA,
T.
TAKAHASHI,
and
T.
SUZIKI.
J.
Nutr.
71,
176
(1960).
14.
I.
NAKAGAWA,
T.
TAKAHASHI,
and
T.
SUZIKI.
J.
Nutr.
73,
186
(1961).
15.
I.
NAKAGAWA,
T.
TAKAHASHI,
and
T.
SUZIKI.
J.
Nutr.
74,
401
(1961).
16.
I.
NAKAGAWA,
T.
TAKAHASHI,
T.
SUZIKI,
and
K.
KOBAYASHI.
J.
Nutr.
77,
61
(1962).
17.
R.
BRESSANI,
D.
L.
WILSON,
M.
BEHAR,
and
N.
S.
SCRIMSHAW.
J.
Nutr.
70,
176
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18.
J.
B.
HUTCHINSON,
T.
MORAN,
and
J.
PACE.
Brit.
J.
Nutr.
13,
151
(1959).
19.
N.
W.
FLODIN.
J.
Agr.
Food
Chem.
1,
222
(1953).