C. Nageswara B. S.
of varying energy intake on nitrogen in men on two levels of protein intake1 Rao,2
Narasinga
Rao,3
B. Sc.,
Dip.
increased by
Effect
in five
young
of changing
men
were
with increase in energy
a reduction
obtained
A.
in urinary
energy
nitrogen
Am.J.
levels
Sc.,
and
was 2,249
Five apparently normal healthy young men were the subjects of the study and the details of the subjects are given in Table I. All the subjects were the research staff of our institute and from their activities they fit into the light activity category. During the period of the investigation all the subjects were residing in the Metabolism Unit
Journal
of Clinical
Nutrition
of protein.
Energy
protein
while
and This
was
levels at which
intake.
kcal,
at constant
of protein-40
levels
excretion.
Clin. Nutr. 28: 1116-1121,
and methods
The American
M.
of the diet
at two
intake at both
Subjects
1116
levels
studied
It has long been known that protein utilization and energy intake are closely interrelated. On a fixed adequate level of protein, level of energy intake is the deciding factor in N balance; with a fixed adequate level of energy intake, level of protein intake determines the extent of N balance (I). Recommended dietary allowances of protein are valid only under conditions of adequate energy intake. Diet survey data indicate that in India many subjects ingest adequate amounts of protein with inadequate intakes of energy (2, 3). Under these circumstances, a significant proportion of the ingested protein may be used for energy purposes. It was considered important, therefore, to determine the influence of variation in energy intake on nitrogen metabolism under conditions similar to the dietary situation existing in India. The effect of different levels of energy intake on nitrogen balances in young men on two different levels of protein intake, 40 g and 60 g daily, is reported in this paper. Material
Naidu,2
were different for the two levels of protein
required for zero nitrogen balance protein.
Nadamuni
Ph.D
A BSTRACT balances
Diet.,
intakes
on nitrogen
60 g. Nitrogen brought
nitrogen
balance
about
primarily
equilibrium
was
At 40 g protein intake the energy
it was 2,066 kcal when
intake
the diet provided
60 g
1975.
of the normal
Institute and daily activities.
Design
of the experiment
continued
to
be
engaged
in
their
In each subject, three to seven balance studies were done. Each balance period was of 1 1 days duration, the first 7 days of which served as stabilization period and during the last 4 days urine and feces were collected daily. Urine was collected in toluene and acetic acid. The experimental diets used in this study were mainly based on rice and their composition is shown in Table 2. At each level of protein and energy, the proportion of energy obtained from fat and carbohydrates was kept constant at an approximate ratio of 1:2. Three energy levels, namely, 2,700, 2,400 and 2,100 kcal, were studied with 60 g protein level. At 40 g protein, five levels of energy intake-3,000, 2,700, 2,400, 2,100 and 1,800 kcal/day -were employed. And the diets were given in the descending order of calorie intake. The subjects were weighed regularly at the beginning and at the end of each balance period, using a sensitive lever actuated weighing machine. A nalytical
procedures
Diet.
In each experimental period, a duplicate sample of cooked experimental diet was mixed in the Waring blender and dried to constant weight. An aliquot was used for nitrogen estimation. Urine and feces. Each day’s feces were mixed in a Waring blender and an aliquot taken in duplicate for nitrogen estimation. Twenty-four-hour collections of urine were mixed thoroughly, volume measured and aliquots taken for the estimation of total nitrogen, urea N and creatinine.
‘From
the
National
Institute of Nutrition,
Council of Medical Research, bad, 500007, India. 2 Assistant Research Officer.
28:
OCTOBER
1975,
pp.
Jamai
1116-1121.
Osmania, 3Assistant
Printed
Indian Hydera-
Director.
in U.S.A.
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/10/1116/4716641 by East Carolina University Health Sciences Library user on 13 January 2019
Influence balance
INFLUENCE
OF
ENERGY
INTAKE
ON
TABLE 1 Details of the subjects Age, years
Height, cm
Weight, kg
CN NB KM VJ RN
35 24 25 31 22
161.3 164.7 166.6 159.0 164.5
64.4 50.8 55.6 47.4 49.2
TABLE 2 Composition
and nutritive value of the experimental Item,
g
Rice Redgramdal Milk Skimmed milk powder Vegetables Sugar Groundnut oil Sago Corn starch Nutritive value Energy, kcal Protein,g
Diet
I
300
55 500 350. 70 72 30
2,700 60
Diet
1117
all the subjects on 60 g protein were in positive N balance on an intake of both 2,700 kcal and 2,400 kcal, they were all in negative balance when the intake was lowered to 2,100 kcal. On 40 g protein intake it was observed that one of the subjects continued to maintain his N balance around equilibrium irrespective of the changes in energy intake with only slight fluctuations on either side of zero balance. Of the other three subjects two were in positive N balance at 2,700, 2,400 and 2, 100 kcal levels and showed negative balance at I ,800 kcal intake. The fourth subject was in positive balance at 3,000 and 2,700 kcal intakes and showed negative balance at 2,400 kcal intake itself. Three out of the five subjects were studied both at 40 and 60 g protein levels. Two of them who were in negative N balance at an intake of 2,400 kcal on 40 g protein diet were in positive balance on a similar energy intake when the protein intake was raised to 60 g. The third subject CN, however, showed an opposite trend. His N balance at 2,100 kcal level on 60 g protein diet was negative while on 40 g protein diet on the same calorie intake the N balance was positive. This was possibly due to much higher excretion of fecal N on the 60 g protein diet than on the 40 g protein
Results The values of fecal and urinary N on each day are shown in Fig. 1 and the average individual values of N excretion, N balance and body weight changes are given in Table 3. Both at 40 g and 60 g of protein intake urinary nitrogen increased in all subjects with a decrease in energy intake. Only in the case of subject CN was there a reduction in urinary N excretion when the calorie intake was reduced from 2,700 to 2,400 during the 60 g protein period. Urea nitrogen expressed as percent of urinary nitrogen was unaltered at different levels of energy intake. The figures for urea N as percent of total urinary N observed in this study were however within the normal ranges reported by other Indian workers (6-9). Nitrogen balance tended to decrease with decrease in energy intake at both the protein levels. However, the change was less consistent than that observed with urinary N. While
Subj
BALANCE
diet. In general the subjects maintained their body weights during the experimental periods although there was a slight tendency for the body weights to decrease with decrease in energy intake. However, there were a few exceptions caused probably by the slight
diets 2
300 50 180 25 350 32 75
2,400 60
Diet
3
300
55 120 30 350 30 53
2,100 60
Diet
4
Diet
5
Diet
6
Diet
7
Diet
8
260 30 240
260 30 240
260 30 240
260 30 240
260 30 240
270 60 87 37 140
270 75 76 37 75
270 52 65 30
270 40 54
270 37 43
55
47
3,000 40
2,700 40
2,400 40
2,100 40
1,800 40
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/10/1116/4716641 by East Carolina University Health Sciences Library user on 13 January 2019
Nitrogen in diet, feces and urine was estimated by macro-Kjeldahl procedure. Urea N was determined by the method of VanSlyke and Cullen (4). Creatinine in urine was estimated by the method of Clark and Thompson (5).
NITROGEN
NAGESWARA
1118
RAO
ET
AL.
204-.
20
6-
42-. 04-
2..... 0..
Energy (KcaI) Prein (g
.................60
__________________ 40 FIG.
variations
ties
of the
I. Daily
the intensity of the individual subjects.
excretions
daily
in
60
of urinary
activi-
Discussion There experimental
been animals
a
number
and
of in
human
studies
in
subjects
effect of energy intake on N utilizaThe effects of both surfeit calories and insufficient calories on N balance have been studied. Increase in N balance with increase in energy intake on constant intake of protein has been reported in rats (10). Cuthbertson and Munro (11) observed in a young man that addition of 780 kcal to a diet providing 2,890 kcal (46 kcal/kg) and 66 g protein (1 g/kg) per day resulted in a 34% decrease in urinary N excretion. Beattie et al. (12) reported that it was possible to obtain a significant positive N balance in undernourished men on N intakes as low as 0.17 g/kg provided the calorie intake exceeds 35 kcal/kg. A reduction in N retention and efficiency of protein utilization when energy on
tion.
the
have
and
fecal
________
______ 40 _______
nitrogen.
intake is restricted has been documented in several species of animals (13-15). In most of the studies the aim was not to elucidate the exact relationship between energy intake and protein utilization in the practical range of protein and energy intakes. This can be studied effectively only when the protein content of the diet is well controlled and the levels of energy intake are varied. In the present investigation in which the protein intake was kept constant, a gradual but significant decrease in the urinary N excretion was noticed with the increase in energy intake. Alterations in urinary N in response to changes in energy intake were more consistent than alterations in N balance. This was primarily due to variation in fecal N excretion. While the coefficient of variation in urinary N excretion was only 6 and 11% at 60 and 40 g protein levels, respectively, it was 30 and 54% in fecal N excretion at the two protein levels. Analysis of variance (Table 4)
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/10/1116/4716641 by East Carolina University Health Sciences Library user on 13 January 2019
4...
INFLUENCE
ENERGY
INTAKE
--
0
r.4
t
(1
o
-
r.4r’-
r-4
-
-8
0
00
00-
0 0
“
00
.‘
-
00
‘
-
r’i
000
-
00
o
or-it I
I
I
‘
ON
NITROGEN
BALANCE
I I 19
indicated that there was no significant difference in fecal N between individuals, between days or between calorie levels either at 40 or 60 g protein level. Therefore, in the statistical evaluation of the relationship between energy intake and N utilization only the urinary N data was considered. Analysis of variance of the data (Table 5) showed that while the differences in urinary N between the days and between individuals were not significant, the differences between calorie levels were highly significant. The significant F value at 5% level found for the interaction between individuals and the energy intakes also suggests that within each individual the differences between calorie intakes were significant. The interactions between energy and days as well as between individuals and days were found to be not significant. A significant linear relationship was observed between urinary N and energy intake on both levels of protein intake. This is shown in Fig. 2. The regression equations calculated from the urinary N and energy intake are Y 10.4363 0.00 1597 X in the case of diets providing 60 g protein and Y = 6.2830 0.000867 X in the case of diets containing 40 g protein where Y urinary N in grams and X energy intake in kilocalories. These equations were employed to compute the energy intake for N equilibrium (zero N balance) at two levels of protein intake. For this, expected urinary N (Y) at N equilibrium was calculated by deducting the mean fecal N from intake. Since fecal N excretion was not related either to protein or calorie intake, average fecal N of all the subjects during the 60 g protein (2.5 g) and 40 g protein (2.2 g), respectively, were used. The expected urinary N (viz, intake-fecal nitrogen) values at N equilibrium from the above calculations were found to be 7.1 g and 4.3 g =
-
-
=
. C)
00 0
a .0 U
oor
r
-00
.0
00 C)
r-.-
r
0 .0 . 00
C
a
Nr.1riri
r’i
Or’000r
C
C) U
C
a a
00
.0 C C) 0/1
j
0 00 C
.
C 0 C)
U ‘C C) C C)
00 0
,
r4
ei
.
z .
-J
,
=
for 60 and 40 g protein intakes, respectively. From these equations it was found that the energy intake for N equilibrium was 2,066 kcal at a protein level of 60 g and 2,249 kcal at 40 g protein intake. The slopes of the two curves appeared to be different although this difference was not statistically significant. Nevertheless, these curves show that the trend to lower the urinary N with increased energy intake was more with an intake of 60 g protein than with
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/10/1116/4716641 by East Carolina University Health Sciences Library user on 13 January 2019
0
OF
1120
NAGESWARA
for the data on fecal N
and energy
ET
AL.
intake 40 g Protein
60 g Protein Source
of variation
Mean
Degrees of
Degrees
F
of
Mean
freedom
of squares
freedom
Betweenenergylevels Between individuals Betweendays
sum
sum
F
of squares
2 3 3
1.2843 0.4476 0.1409
NS NS NS
4 3 3
0.3398 0.0549 0.1354
NS NS NS
6 6 9 13 42
0.5467 0.5482 0.7088 0.5788
NS NS NS NS
12 12 9 12
0.0764 0.4559 0.9118 1.4855
NS NS NS NS
Interaction Energy levels x individuals Energy levels x days Individuals x days Error Total
TABLE Analysis
5 of variance
for
the
data
on
urinary
55
N and
energy
intake
60 g Protein Source
of variation
of
Degrees
Mean
40 g Protein
sum
Degrees of freedom
F
Mean sum of squares
F
freedom
of squares
2 3 3
3.3171 0. 1018 0.2149
18.969” NS NS
4 3 3
1.9023 0.4 188 0.1760
8.815” NS NS
6 6 9 14 43
0.5263 0.2493 0.4393 0.1748
3.010’ NS NS
12 12 9 12 55
0.5767 0.2280 0.1203 0.2158
2.672c NS NS
Betweenenergylevels Between individuals Between days
Interaction Energy Energy
levels levels
x individuals x days x days
0.001.
“P
Individuals
Error Total “P
of varying energy intake on nitrogen in men on two levels of protein intake1 Rao,2
Narasinga
Rao,3
B. Sc.,
Dip.
increased by
Effect
in five
young
of changing
men
were
with increase in energy
a reduction
obtained
A.
in urinary
energy
nitrogen
Am.J.
levels
Sc.,
and
was 2,249
Five apparently normal healthy young men were the subjects of the study and the details of the subjects are given in Table I. All the subjects were the research staff of our institute and from their activities they fit into the light activity category. During the period of the investigation all the subjects were residing in the Metabolism Unit
Journal
of Clinical
Nutrition
of protein.
Energy
protein
while
and This
was
levels at which
intake.
kcal,
at constant
of protein-40
levels
excretion.
Clin. Nutr. 28: 1116-1121,
and methods
The American
M.
of the diet
at two
intake at both
Subjects
1116
levels
studied
It has long been known that protein utilization and energy intake are closely interrelated. On a fixed adequate level of protein, level of energy intake is the deciding factor in N balance; with a fixed adequate level of energy intake, level of protein intake determines the extent of N balance (I). Recommended dietary allowances of protein are valid only under conditions of adequate energy intake. Diet survey data indicate that in India many subjects ingest adequate amounts of protein with inadequate intakes of energy (2, 3). Under these circumstances, a significant proportion of the ingested protein may be used for energy purposes. It was considered important, therefore, to determine the influence of variation in energy intake on nitrogen metabolism under conditions similar to the dietary situation existing in India. The effect of different levels of energy intake on nitrogen balances in young men on two different levels of protein intake, 40 g and 60 g daily, is reported in this paper. Material
Naidu,2
were different for the two levels of protein
required for zero nitrogen balance protein.
Nadamuni
Ph.D
A BSTRACT balances
Diet.,
intakes
on nitrogen
60 g. Nitrogen brought
nitrogen
balance
about
primarily
equilibrium
was
At 40 g protein intake the energy
it was 2,066 kcal when
intake
the diet provided
60 g
1975.
of the normal
Institute and daily activities.
Design
of the experiment
continued
to
be
engaged
in
their
In each subject, three to seven balance studies were done. Each balance period was of 1 1 days duration, the first 7 days of which served as stabilization period and during the last 4 days urine and feces were collected daily. Urine was collected in toluene and acetic acid. The experimental diets used in this study were mainly based on rice and their composition is shown in Table 2. At each level of protein and energy, the proportion of energy obtained from fat and carbohydrates was kept constant at an approximate ratio of 1:2. Three energy levels, namely, 2,700, 2,400 and 2,100 kcal, were studied with 60 g protein level. At 40 g protein, five levels of energy intake-3,000, 2,700, 2,400, 2,100 and 1,800 kcal/day -were employed. And the diets were given in the descending order of calorie intake. The subjects were weighed regularly at the beginning and at the end of each balance period, using a sensitive lever actuated weighing machine. A nalytical
procedures
Diet.
In each experimental period, a duplicate sample of cooked experimental diet was mixed in the Waring blender and dried to constant weight. An aliquot was used for nitrogen estimation. Urine and feces. Each day’s feces were mixed in a Waring blender and an aliquot taken in duplicate for nitrogen estimation. Twenty-four-hour collections of urine were mixed thoroughly, volume measured and aliquots taken for the estimation of total nitrogen, urea N and creatinine.
‘From
the
National
Institute of Nutrition,
Council of Medical Research, bad, 500007, India. 2 Assistant Research Officer.
28:
OCTOBER
1975,
pp.
Jamai
1116-1121.
Osmania, 3Assistant
Printed
Indian Hydera-
Director.
in U.S.A.
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/10/1116/4716641 by East Carolina University Health Sciences Library user on 13 January 2019
Influence balance
INFLUENCE
OF
ENERGY
INTAKE
ON
TABLE 1 Details of the subjects Age, years
Height, cm
Weight, kg
CN NB KM VJ RN
35 24 25 31 22
161.3 164.7 166.6 159.0 164.5
64.4 50.8 55.6 47.4 49.2
TABLE 2 Composition
and nutritive value of the experimental Item,
g
Rice Redgramdal Milk Skimmed milk powder Vegetables Sugar Groundnut oil Sago Corn starch Nutritive value Energy, kcal Protein,g
Diet
I
300
55 500 350. 70 72 30
2,700 60
Diet
1117
all the subjects on 60 g protein were in positive N balance on an intake of both 2,700 kcal and 2,400 kcal, they were all in negative balance when the intake was lowered to 2,100 kcal. On 40 g protein intake it was observed that one of the subjects continued to maintain his N balance around equilibrium irrespective of the changes in energy intake with only slight fluctuations on either side of zero balance. Of the other three subjects two were in positive N balance at 2,700, 2,400 and 2, 100 kcal levels and showed negative balance at I ,800 kcal intake. The fourth subject was in positive balance at 3,000 and 2,700 kcal intakes and showed negative balance at 2,400 kcal intake itself. Three out of the five subjects were studied both at 40 and 60 g protein levels. Two of them who were in negative N balance at an intake of 2,400 kcal on 40 g protein diet were in positive balance on a similar energy intake when the protein intake was raised to 60 g. The third subject CN, however, showed an opposite trend. His N balance at 2,100 kcal level on 60 g protein diet was negative while on 40 g protein diet on the same calorie intake the N balance was positive. This was possibly due to much higher excretion of fecal N on the 60 g protein diet than on the 40 g protein
Results The values of fecal and urinary N on each day are shown in Fig. 1 and the average individual values of N excretion, N balance and body weight changes are given in Table 3. Both at 40 g and 60 g of protein intake urinary nitrogen increased in all subjects with a decrease in energy intake. Only in the case of subject CN was there a reduction in urinary N excretion when the calorie intake was reduced from 2,700 to 2,400 during the 60 g protein period. Urea nitrogen expressed as percent of urinary nitrogen was unaltered at different levels of energy intake. The figures for urea N as percent of total urinary N observed in this study were however within the normal ranges reported by other Indian workers (6-9). Nitrogen balance tended to decrease with decrease in energy intake at both the protein levels. However, the change was less consistent than that observed with urinary N. While
Subj
BALANCE
diet. In general the subjects maintained their body weights during the experimental periods although there was a slight tendency for the body weights to decrease with decrease in energy intake. However, there were a few exceptions caused probably by the slight
diets 2
300 50 180 25 350 32 75
2,400 60
Diet
3
300
55 120 30 350 30 53
2,100 60
Diet
4
Diet
5
Diet
6
Diet
7
Diet
8
260 30 240
260 30 240
260 30 240
260 30 240
260 30 240
270 60 87 37 140
270 75 76 37 75
270 52 65 30
270 40 54
270 37 43
55
47
3,000 40
2,700 40
2,400 40
2,100 40
1,800 40
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/10/1116/4716641 by East Carolina University Health Sciences Library user on 13 January 2019
Nitrogen in diet, feces and urine was estimated by macro-Kjeldahl procedure. Urea N was determined by the method of VanSlyke and Cullen (4). Creatinine in urine was estimated by the method of Clark and Thompson (5).
NITROGEN
NAGESWARA
1118
RAO
ET
AL.
204-.
20
6-
42-. 04-
2..... 0..
Energy (KcaI) Prein (g
.................60
__________________ 40 FIG.
variations
ties
of the
I. Daily
the intensity of the individual subjects.
excretions
daily
in
60
of urinary
activi-
Discussion There experimental
been animals
a
number
and
of in
human
studies
in
subjects
effect of energy intake on N utilizaThe effects of both surfeit calories and insufficient calories on N balance have been studied. Increase in N balance with increase in energy intake on constant intake of protein has been reported in rats (10). Cuthbertson and Munro (11) observed in a young man that addition of 780 kcal to a diet providing 2,890 kcal (46 kcal/kg) and 66 g protein (1 g/kg) per day resulted in a 34% decrease in urinary N excretion. Beattie et al. (12) reported that it was possible to obtain a significant positive N balance in undernourished men on N intakes as low as 0.17 g/kg provided the calorie intake exceeds 35 kcal/kg. A reduction in N retention and efficiency of protein utilization when energy on
tion.
the
have
and
fecal
________
______ 40 _______
nitrogen.
intake is restricted has been documented in several species of animals (13-15). In most of the studies the aim was not to elucidate the exact relationship between energy intake and protein utilization in the practical range of protein and energy intakes. This can be studied effectively only when the protein content of the diet is well controlled and the levels of energy intake are varied. In the present investigation in which the protein intake was kept constant, a gradual but significant decrease in the urinary N excretion was noticed with the increase in energy intake. Alterations in urinary N in response to changes in energy intake were more consistent than alterations in N balance. This was primarily due to variation in fecal N excretion. While the coefficient of variation in urinary N excretion was only 6 and 11% at 60 and 40 g protein levels, respectively, it was 30 and 54% in fecal N excretion at the two protein levels. Analysis of variance (Table 4)
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/10/1116/4716641 by East Carolina University Health Sciences Library user on 13 January 2019
4...
INFLUENCE
ENERGY
INTAKE
--
0
r.4
t
(1
o
-
r.4r’-
r-4
-
-8
0
00
00-
0 0
“
00
.‘
-
00
‘
-
r’i
000
-
00
o
or-it I
I
I
‘
ON
NITROGEN
BALANCE
I I 19
indicated that there was no significant difference in fecal N between individuals, between days or between calorie levels either at 40 or 60 g protein level. Therefore, in the statistical evaluation of the relationship between energy intake and N utilization only the urinary N data was considered. Analysis of variance of the data (Table 5) showed that while the differences in urinary N between the days and between individuals were not significant, the differences between calorie levels were highly significant. The significant F value at 5% level found for the interaction between individuals and the energy intakes also suggests that within each individual the differences between calorie intakes were significant. The interactions between energy and days as well as between individuals and days were found to be not significant. A significant linear relationship was observed between urinary N and energy intake on both levels of protein intake. This is shown in Fig. 2. The regression equations calculated from the urinary N and energy intake are Y 10.4363 0.00 1597 X in the case of diets providing 60 g protein and Y = 6.2830 0.000867 X in the case of diets containing 40 g protein where Y urinary N in grams and X energy intake in kilocalories. These equations were employed to compute the energy intake for N equilibrium (zero N balance) at two levels of protein intake. For this, expected urinary N (Y) at N equilibrium was calculated by deducting the mean fecal N from intake. Since fecal N excretion was not related either to protein or calorie intake, average fecal N of all the subjects during the 60 g protein (2.5 g) and 40 g protein (2.2 g), respectively, were used. The expected urinary N (viz, intake-fecal nitrogen) values at N equilibrium from the above calculations were found to be 7.1 g and 4.3 g =
-
-
=
. C)
00 0
a .0 U
oor
r
-00
.0
00 C)
r-.-
r
0 .0 . 00
C
a
Nr.1riri
r’i
Or’000r
C
C) U
C
a a
00
.0 C C) 0/1
j
0 00 C
.
C 0 C)
U ‘C C) C C)
00 0
,
r4
ei
.
z .
-J
,
=
for 60 and 40 g protein intakes, respectively. From these equations it was found that the energy intake for N equilibrium was 2,066 kcal at a protein level of 60 g and 2,249 kcal at 40 g protein intake. The slopes of the two curves appeared to be different although this difference was not statistically significant. Nevertheless, these curves show that the trend to lower the urinary N with increased energy intake was more with an intake of 60 g protein than with
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/10/1116/4716641 by East Carolina University Health Sciences Library user on 13 January 2019
0
OF
1120
NAGESWARA
for the data on fecal N
and energy
ET
AL.
intake 40 g Protein
60 g Protein Source
of variation
Mean
Degrees of
Degrees
F
of
Mean
freedom
of squares
freedom
Betweenenergylevels Between individuals Betweendays
sum
sum
F
of squares
2 3 3
1.2843 0.4476 0.1409
NS NS NS
4 3 3
0.3398 0.0549 0.1354
NS NS NS
6 6 9 13 42
0.5467 0.5482 0.7088 0.5788
NS NS NS NS
12 12 9 12
0.0764 0.4559 0.9118 1.4855
NS NS NS NS
Interaction Energy levels x individuals Energy levels x days Individuals x days Error Total
TABLE Analysis
5 of variance
for
the
data
on
urinary
55
N and
energy
intake
60 g Protein Source
of variation
of
Degrees
Mean
40 g Protein
sum
Degrees of freedom
F
Mean sum of squares
F
freedom
of squares
2 3 3
3.3171 0. 1018 0.2149
18.969” NS NS
4 3 3
1.9023 0.4 188 0.1760
8.815” NS NS
6 6 9 14 43
0.5263 0.2493 0.4393 0.1748
3.010’ NS NS
12 12 9 12 55
0.5767 0.2280 0.1203 0.2158
2.672c NS NS
Betweenenergylevels Between individuals Between days
Interaction Energy Energy
levels levels
x individuals x days x days
0.001.
“P
Individuals
Error Total “P
