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Vol. 44 (2), Oct. 2009, Page 21
Amino Acid Recommendations for laying hens
Andreas Lemme
Evonik - Deguss GmbH, Germany
Introduction
During recent decades productivity of laying hens increased substantially (Elliot, 2008). Not only egg
number, egg mass, and feed conversion has increased but also persistency of lay has improved. As
such, this must have implications on the optimal amino acid nutrition of current laying hen strains.
Simply stated, increasing egg mass output per hen means an increased amino acid output which has
to be provided by the feed. Moreover, while performance criteria of laying hens have improved, body
weight has decreased (Elliot, 2008). Consequently, the amino acid requirement for maintenance
purposes is influenced. In addition to the quantitative demands for amino acids by the modern laying
hen changing, there also is the potential that the qualitative demands for dietary protein might have
changed as optimum amino acid composition for egg production differs from that for maintenance.
Therefore, the current amino acid recommendations for layers provided by Evonik Degussa Feed
Additives have been revised. Since methionine is considered the first limiting amino acid in most
common diet compositions, literature was screened for methionine response studies in order to derive
a value for optimum dietary methionine level. Subsequently, the optimum amino acid profile was
defined by means of recent ideal protein research which ultimately allowed for calculating optimal
dietary amino acid levels for modern laying hen strains.
Several methionine dose response studies with laying hens are available
International literature was searched for methionine dose-response studies with laying hens in order
to perform a meta-analysis. Thirteen papers were published since 1990 reporting 19 experiments
which were suitable for this survey (Table 1). Age of laying hens ranged between 18 and 64 weeks but
on average trials were performed from 24 to 39 weeks of age. Moreover, various genetics were used
in these trials including Hy-Line W-36, Lohmann LSL, Lohmann brown, Single Comb White Leghorn,
Hisex brown, Dekalb delta, and ISA Babcock hens. However, because of the limited number of trials,
it was not possible to derive specific amino acid recommendations for individual strains.
There were considerable differences in diet compositions between these trials as the ingredients
used, protein and amino acid levels, and metabolisable energy contents varied. At least it can be
stated that all basal diets were deficient in methionine (Met) and methionine+cysteine (Met+Cys),
otherwise the hens would not have responded to increasing levels of supplemental DL-Met. In order
to avoid or at least to reduce interactions between performance data and digestibility of the dietary
Met, all performance data were regressed against digestible Met or Met+Cys. However, some publi-
cations only reported total amino acid contents of the diets, and in those cases, the digestible amino
acid levels of the diets were recalculated using AminoDat 3.0
®
software (Degussa 2006). Digestibility
figures origin from broiler research as digestibility research on laying hens is scarce.
The basic idea of meta-analyses is to put data of many experiments together in order to analyse them
in one process. In this context the challenge of the present survey was dealing with high variation of
response data within a trial but particularly between trials. In order to reduce this variability, egg mass
per hen per day was considered as key performance parameter. However, when egg mass/hen/day
was plotted against dietary digestible Met content, data were still relatively variable and regression
analysis revealed a relative poor fit (r
2
= 0.24, Figure 1). One goal of the nutritionist is to ensure a
least intake of nutrients which is the result of dietary concentration and feed intake. As feed intake is
influenced by a number of factors such as body weight (an effect of strain) nutrient intake is consid-
ered to be a better basis for standardisation. Therefore, the data were standardised to digestible
methionine intake.
Physiological feed back mechanisms allow laying hens to eat according to the first limiting nutritional
factor, which is usually dietary energy. So, differences in dietary energy levels must have implications
Amino Acid Recommendations for laying hens
Vol. 44 (2), Oct. 2009, Page 22
on feed intake and consequently on Met intake. Regressing daily egg mass data against daily digestible
Met intake per MJ ME improved the fit of the regression curve to a reasonable r-square of 0.78
(Figure 2).
Finally, data were analysed by exponential regression as suggested by Morris (2004), who demonstrated
that performance response curves to amino acid levels of a population of animals are of non-linear
nature. The 19 experiments delivered 97 data points, and the resulting regression equation suggested
that 35.15 mg Met intake/MJ ME/hen/d is optimal (95 % of asymptotic response). This number cor-
Amino Acid Recommendations for laying hens
Authors Year
Expe-
riment
strain period CP ME
dig.
Met*
tot
Met
dig
M+C
tot
M+C
dig.
Lys
tot.
Lys
Bateman et
al, 2005
2001
Hy-Line W-
36
24 35 15.0 12.00 0.25 0.27 0.45 0.51 0.65 0.75
Bertram et
al., 1995a
1995
high
energy
Lohmann
LSL
24 36 14.8 11.72 0.22 0.25 0.42 0.51 0.71 0.79
Bertram et
al., 1995a
1995
low
energy
Lohmann
LSL
24 36 15.1 10.88 0.22 0.25 0.42 0.50 0.71 0.79
Bertram et
al., 1995b
1995
Lohmann
Brown
23 35 15.6 11.70 0.19 0.23 0.39 0.50 0.68 0.77
Calderon and
Jensen, 1990
1990 Expt. 1
Comb White
Leghorn
32 36 13.0 12.18 0.20 0.24 0.40 0.45 0.61 0.68
Calderon and
Jensen, 1990
1990 Expt. 2
Comb White
Leghorn
59 64 13.0 12.18 0.20 0.24 0.40 0.45 0.61 0.68
Dänner and
Bessei, 2002
2002
Lohmann
LSL
22 45 15.1 11.39 0.19 0.22 0.43 0.49 0.75 0.84
Filho et al.,
2006
2006 Hisex brown 20 44 17.2 11.72 0.29 0.31 0.54 0.61 0.84 0.97
Fuente
Martinez
et al., 2005
2005
ISA Babcock
B-300
24 34 15.2 12.13 0.21 0.24 0.41 0.49 0.69 0.79
Lemme et
al., 2004
2003
Hy-Line
W-36
24 40 14.5 11.84 0.21 0.23 0.40 0.48 0.72 0.80
Lemme et al.,
2004
2003
Lohmann
Brown
22 46 15.4 11.80 0.20 0.23 0.42 0.50 0.80 0.88
Mack et al.,
1999
1999
Dekalb
delta
Dekalb delta 18 30 14.6 11.92 0.21 0.22 0.43 0.46 0.65 0.73
Mack et al.,
1999
1999
Hy-Line
W-36
Hy-Line
W-36
18 30 14.6 11.92 0.21 0.22 0.43 0.46 0.65 0.73
Mack et al.,
1999
1999
Lohmann
LSL
Lohmann
LSL
18 30 14.6 11.92 0.21 0.22 0.43 0.46 0.65 0.73
Narváez,
1996
1996
brown
layers
not
mentioned
22 38 14.4 11.51 0.21 0.23 0.44 0.48 0.62 0.71
Narváez et
al., 2005
1996
white
layers
Lohmann
LSL
22 38 14.4 11.51 0.21 0.23 0.44 0.48 0.62 0.71
Novak et al.,
2004
2004 high Lys Dekalb delta 20 43 17.7 12.09 0.31 0.36 0.55 0.66 0.90 0.98
Novak et al..,
2004
2004 low Lys Dekalb delta 20 43 17.7 12.09 0.32 0.36 0.56 0.65 0.81 0.87
Schutte et al.,
1994
1994 Expt. 1
Lohmann
LSL
25 37 14.5 12.13 0.20 0.23 0.41 0.48 0.68 0.77
Table 1: Methionine and Methionine+Cysteine dose response studies which were considered
in the meta-analysis
Vol. 44 (2), Oct. 2009, Page 23
responds to a daily intake of 415 mg of Met using a dietary energy level of 11.82 MJ ME, which was
the average across all considered studies. This number of 415 mg dig. Met/hen/d is about 6 % higher
than our current recommendation (390 mg/hen/d) but in line with that suggested by Joly (2007), who
estimated 420 mg dig. Met/hen/d.
The procedure applied for digestible methionine was also applied for digestible methionine + cysteine
levels (Figure 3). Accordingly, the resulting optimum is 65.76 mg digestible Met+Cys intake/MJ
ME/hen/d corresponding to 777 mg dig. Met+Cys/hen/d. This value is about
13 % higher than the current Evonik recommendation of 690 mg/hen/d.
While the determined optimum supply of 415 mg dig. Met/hen/d and 777 mg dig. Met+Cys/hen/d may
initially seem high, these levels suggest an optimum dig. Met to dig. Met+Cys ratio of 54 %. This ratio
is similar to that suggested by Bregendahl et al. (2008), who determined an optimum dig. Met to
Amino Acid Recommendations for laying hens
15
25
35
45
55
65
024681012
dig. Met g/kg feed
egg mass, g/d
Y = 36.93 + 16.18 * (1 – e
(-1.35 * (X – 1.9))
)
r
2
= 0.244; n = 97
15
25
35
45
55
65
024681012
dig. Met g/kg feed
egg mass, g/d
Y = 36.93 + 16.18 * (1 – e
(-1.35 * (X – 1.9))
)
r
2
= 0.244; n = 97
15
25
35
45
55
65
5 10152025303540455055
dig. Met intake, mg/MJ ME/d
egg mass, g/d
Y = 23.90 + 32.17 * (1 – e
(-0.125 * (X – 11.11))
)
r
2
= 0.775; n = 97
95% asympt. Response: 35.15 mg dig. Met/MJ ME/d
15
25
35
45
55
65
5 10152025303540455055
dig. Met intake, mg/MJ ME/d
egg mass, g/d
Y = 23.90 + 32.17 * (1 – e
(-0.125 * (X – 11.11))
)
r
2
= 0.775; n = 97
95% asympt. Response: 35.15 mg dig. Met/MJ ME/d
Figure 1: Daily egg mass data out of 19 experiments plotted against the digestible methionine
content of the diet
Figure 2: Daily egg mass data out of 19 experiments plotted against the daily digestible
methionine intake which was standardised to the dietary energy content
Vol. 44 (2), Oct. 2009, Page 24
Met+Cys ratio of 52 and 55 % based on daily egg mass and feed conversion ratio data out of two
consecutive experiments, respectively. It also agrees with Rostagno (2005), who recommended a
dig. Met to Met+Cys ratio of 55 %. However, this estimate is lower than Joly (2007), who suggested
650 mg dig. Met+Cys/hen/d to be optimal which would corresponds to a dig. Met to Met+Cys ratio of
65 %. The ratio of Joly (2007) suggests a considerably lower Cys requirement of the birds as the dig.
Met level by Joly (2007) is quite in line with our findings. Finally, suggestions by Leeson and Summers
(2005) and Coon and Zhang (1999) were 58 % and 60 %, which are slightly higher than our findings,
but lower than those of Joly (2007).
Ideal Protein Profiles
Although Met and Met+Cys, respectively, play a key role in laying hen nutrition because they are first
limiting in most common commercial diets, lysine is typically used as the reference amino acid in the
Ideal Protein concept. The advantage of this concept is that all essential amino acids are considered
because optimising performance requires that the whole range of essential amino acids are provided
to the animal in adequate amounts. Recently, Bregendahl
et al
. (2008) published an extended study
on the Ideal Protein profile of modern laying hens, but there are several other references for this topic
including Jais
et al
.(1995), Coon and Zhang (1999), Rostagno (2005) and Leeson and Summers
(2005). Respective ideal protein profiles are listed in Table 2.
There is a good consistency between the suggested profiles although methodologies applied to derive
the values differed with a couple of exceptions. For example, compared with all other studies indi-
cating an average value of 50 % for the dig. Met to Lys ratio, Jais et al. (1995) reported 44 %, which
seemed to be too low. Suggested Met+Cys to Lys ratios ranged from 81 % (Coon and Zhang, 1999)
to 96 % (Bregendahl
et al
., 2008) and showed thus higher variability. With respect to Thr, Leeson and
Summers (2005) suggested a relatively high ratio to Lys (80 %) whereas Rostagno (2005) recom-
mends a rather low figure (66 %). Regarding Trp:Lys the ratio provided by Jais
et al
.(1995) was
substantially lower compared to the other references. Likewise, the suggested Arg to Lys ratio of
130 % by Coon and Zhang (1999) is considerably higher than those by Rostagno (2005) and Leeson
and Summers (2005) and especially by Jais
et al.
(1995). Similar findings apply for Val to Lys ratios.
Ile to Lys ratios varied between 76 % and 86 %.
Amino Acid Recommendations for laying hens
Figure 3: Daily egg mass data out of 19 experiments plotted against the daily digestible
methionine+cysteine intake which was standardised to the dietary energy content
15
25
35
45
55
65
15 20 25 30 35 40 45 50 55 60 65 70 75 80
dig. Met+Cys intake, mg/MJ ME/d
egg mass, g/d
Y = 24.0 + 34.04 * (1 – e
(-0.068 * (X – 21.94))
)
r
2
= 0.791; n = 97
95% asympt. Response: 65.75 mg dig. Met+Cys/MJ ME/d
15
25
35
45
55
65
15 20 25 30 35 40 45 50 55 60 65 70 75 80
dig. Met+Cys intake, mg/MJ ME/d
egg mass, g/d
Y = 24.0 + 34.04 * (1 – e
(-0.068 * (X – 21.94))
)
r
2
= 0.791; n = 97
95% asympt. Response: 65.75 mg dig. Met+Cys/MJ ME/d
Vol. 44 (2), Oct. 2009, Page 25
Table 2: Ideal amino acid profiles proposed by different authors
Recommended amino acid levels for layers have been increased
Based on our meta-analysis and the above mentioned ideal protein sources we revised our current
amino acid recommendations for laying hens, which are reported in Table 3. The basis of our revised
recommendations is the optimum daily intake of 415 mg dig. Met/hen which was the outcome of our
meta-analysis. In a second step, optimal intake of the other amino acids was calculated by using the
ideal ratios which are presented in Table 3. Those ratios were more or less the average of the numbers
given in Table 2. The Met to Lys as well as the Trp to Lys ratio reported by Jais
et al.
(1995) were
excluded. For the optimal Met+Cys to Lys ratio also the Met to Met+Cys ratio derived from our meta
analysis was considered. Although numbers in Table 2 suggest a Thr to Lys ratio of 74 % we rather
suggest to use a ratio of 70 %. Variation of literature data is large. Ratios referring to Bregendahl
et
al
. (2008) refer to daily egg mass data. However, feed conversion responses suggested a ratio of
67 %. In addition, information from layer feed producers also suggests that optimal ratio might be
lower than 74 %.
An intake of 415 mg dig. Met/hen/d and an optimum dig. Met to Lys ratio of 50 % revealed a daily
dig. Lys intake of 830 mg/hen/d (Table 3). Then, dietary levels were calculated using optimum daily
intakes and assuming varying daily feed intakes from 80 to 120 g (Table 3). Accordingly, the concen-
tration of amino acids (and ideally other nutrients and energy) increases with decreasing feed intake.
A recommended daily intake of 830 mg dig. Lys/hen might appear high, especially when compared with
our previous recommendation of 770 mg/hen/d. However, in an experiment by Bonekamp
et al
. (2007),
dig. Lys intake was increased from 550 to 800 mg/hen/d in two layer strains (Lohmann brown classic,
Lohmann LSL classic). Note that in this trial, the whole amino acid profile was increased in conjunc-
tion with Lys, whereas energy and minerals were maintained. Responses on daily egg mass and feed
conversion ratio were of non-linear nature (Figure 4). Exponential regression analysis indicated that
the maximum daily egg mass and minimum feed conversion ratio were not achieved. Respective
regression equations suggested that the optimal dig. Lys intakes were higher than the highest tested
level but also clearly higher than 830 mg/hen/d, which imply that modern layers require high levels
of dietary amino acids to realize their full genetic performance potential. Moreover, optimum amino
acid levels for maximising performance seemed to be similar between strains.
Most of the studies used for the meta-analysis on sulphur amino acids and ideal protein were done with
laying hens from start of lay to around peak production. Having typical egg production and egg weight
curves in mind, it appears logic that optimum amino acid levels differ with age. Our recommendations
as given in Table 3 are meant for layers up to peak production. In later phases when performance
decreases, their amino acid requirements will also decrease, thus the dietary amino acid levels might
be reduced.
Amino Acid Recommendations for laying hens
Source
Jais
et al.
,
1995
Leeson and
Summers,
2005
Rostagno,
2005
Bregendahl
et al.
,
2008
Coon and
Zhang, 1999
digestible total digestible digestible digestible digestible
Lys 100 100 100 100 100 100
Met 44 51 50 47 52 49
Met+Cys -- 88 91 94 96 81
Thr 74 80 66 77 -- 73
Trp 16 21 23 22 -- 20
Arg 82 103 100 -- -- 130
Ile 76 79 83 79 -- 86
Val 64 89 90 93 -- 102
Vol. 44 (2), Oct. 2009, Page 26Amino Acid Recommendations for laying hens
The potential for differences in the maintenance and production requirements and their subsequent
differences in their ideal amino acid profiles also should be considered. The ratios suggested by
Rostagno (2005) are applied for various body weights, weight gain, and daily egg mass of the hens
but there is no consideration given to differences in maintenance and production resulting in changes
of the ratios. However, the recommendations by GfE (1999) do consider those differences, but the
recommended amino acid profile changes only marginally. Therefore, our recommended amino acid
ratios (Lys=100) remain the same for all production phases for practical reasons.
Feed intake is influenced by dietary energy
Feed intake of laying hens is dependent on the dietary energy level. Morris (2004) referring to an
earlier work of his lab from 1968 showed that laying hens reduce their feed intake as soon as dietary
metabolisable energy (ME) content has been increased. However, Morris (2004) further reported that
if dietary ME is increased and also the limiting amino acids are increased proportionally, hens gained
fat. He concluded that a reduction in feed intake was not enough to maintain energy intake. As a
solution, Morris (2004) suggested to use the effective energy concept which is more similar to net
energy instead of metabolisable energy. The change in dietary metabolisable energy is often accom-
panied with a change in fibre and fat content, fractions which per definition have different energetic effec-
tiveness. However, the effective energy concept has not been established in poultry nutrition.
An experiment was conducted in which ISA brown layers were fed increasing levels of a well balanced
protein at two metabolisable energy intakes (Wijtten
et al
., 2006). Energy intake of 294 kcal ME/hen/d
and 314 kcal ME/hen/d were achieved by restricted feeding. Digestible Lys intake was increased from
about 600 to 750 mg/hen/d at both energy intakes. At the same time the whole amino acid profile
was raised maintaining ratios between the amino acids. Responses on daily egg mass are shown in
Figure 5. Performance increased in a linear fashion with increasing levels of balanced protein at both
energy intakes suggesting that higher levels would have been needed to achieve the asymptote. This
effect again suggests that the optimal dietary dig. Lys level (and those of all other essential amino
acids) is much higher than our former recommendation of 770 mg dig. Lys/hen/d.
Table 3: Recommendations for both digestible amino acid intake of laying hens and in %
of diet for laying hens with differing daily feed intake (Dietary energy: 11.82 MJ
ME/kg)
dig. Lys dig. Met
dig.
Met+Cys
dig. Thr dig. Trp dig. Arg dig. Ile dig. Val
optimal ratios
to Lys
100 50 91 70 21 104 80 88
intake, mg/d 831 415 756 582 174 864 665 731
Digestible Amino acids in g/kg diet
Feed intake, g/d
80 10.39 5.19 9.45 7.27 2.18 10.80 8.31 9.14
85 9.78 4.89 8.90 6.84 2.05 10.17 7.82 8.60
90 9.23 4.62 8.40 6.46 1.94 9.60 7.39 8.12
95 8.75 4.37 7.96 6.12 1.84 9.10 7.00 7.70
100 8.31 4.15 7.56 5.82 1.74 8.64 6.65 7.31
105 7.91 3.96 7.20 5.54 1.66 8.23 6.33 6.96
110 7.55 3.78 6.87 5.29 1.59 7.86 6.04 6.65
115 7.23 3.61 6.58 5.06 1.52 7.51 5.78 6.36
120 6.92 3.46 6.30 4.85 1.45 7.20 5.54 6.09
Vol. 44 (2), Oct. 2009, Page 27
Figure 5: Daily egg mass of ISA brown layers with graded levels of balanced protein intake
(True fecal digestible Lys given as reference) at two energy intakes (Wijtten
et al.
,
2006)
There was no difference between the two energy treatments indicating that if energy intake is reduced,
amino acid intake should be maintained in order to keep performance at the same level (Figure 5).
Differences in energy intake were achieved by controlling feed intake. Consequently feed conversion
ratio was better at lower energy intake but the response to increasing dietary balanced protein (BP)
Amino Acid Recommendations for laying hens
54.0
55.0
56.0
57.0
58.0
59.0
600 650 700 750 800
TFD Lys intake, mg/d
egg mass, g/d
aimed 285 kcal ME/d
aimed 305 kcal ME/d
Figure 4: Daily egg mass and feed conversion ratio of two layer strains fed graded levels of
balanced protein (Bonekamp
et al.
, 2007)
45.0
50.0
55.0
60.0
65.0
550 600 650 700 750 800 850
TFD Lys intake, mg/d
egg mass, g/d
Lohmann LSL
Lohmann Brown
1.70
1.80
1.90
2.00
2.10
2.20
2.30
550 650 750 850 950
TFD Lys intake, mg/d
feed per EM, kg/kg
Lohmann LSL
Lohmann Brown
Vol. 44 (2), Oct. 2009, Page 28
was again very similar at both energy intakes. Interestingly, both increasing dietary BP and energy
intake levels affected body weight development of the hens over the 16-week experiment. Body weight
increased with increasing BP (Figure 6). It is assumed that effects on body weight are mainly due to
fat accretion, however, this has not been confirmed. Body weight gain was consistently higher at
higher energy intake. Therefore, it was concluded that the higher energy intake could not be utilised
for higher egg mass production, so the extra energy was stored as fat. These responses imply that an
energy intake of 314 kcal ME/hen/d can be reduced as energy is partly used for weight gain which
is not necessarily desired in layers.
Differences in energy intake can only be achieved by feed restriction. In case of changing ME levels
in the diet, hens would respond with changes in feed intake in order to maintain energy intake. However,
the current experiment suggests that controlling energy intake of hens might be a tool to control body
weight (fat) gain of layers.
Raw material prices and availability force nutritionists to find alternative sources and concepts partic-
ularly when it comes to energy. In this context, the question arises how to adjust dietary amino acids
if dietary energy is reduced. As mentioned above, Morris (2004) reported that proportional adjust-
ment of amino acids with changes in dietary metabolisable energy is not satisfying. A recent litera-
ture survey suggests that amino acids levels in broiler diets should not be adjusted proportionally to
changes in dietary energy in order to maintain performance and profitability (Lemme, 2007). Changes
in dietary composition (fat, fibre, carbohydrates, protein) and their respective net energy or effective
energy contents might partly explain this finding. This concept has been implemented in our QuickChick
software, which gives amino acid recommendations for broilers. It suggests that relative changes in
amino acid levels are only half of the dietary ME changes. When applying the same concept to layer
amino acid recommendation, levels would change as presented in Table 4 where ME was reduced by
5 % to 11.23 MJ ME/kg.
Optimal dietary amino acid levels are influenced by economic conditions
Dietary amino acid specifications should allow for high performance. However, maximum performance
does not necessarily mean maximum profitability. Therefore, nutrient specifications in general but
amino acid specification in particular should be adjusted to the economic conditions including feed
cost and egg price. In Figure 7, income over feed cost is used as a profitability indicator. The consid-
erations for this calculation were: a general diet price of 180 EURO; a price increase of 1 EURO per
100 mg increase of daily dig. Lys intake (at 100g daily feed intake this corresponds to an increase of
0.1 % dig. Lys of the balanced protein); and 15 EURO per kg egg mass. These considerations were
combined with predicted daily egg mass and feed conversion ratio using the respective exponential
regression equations. Although the curve of Lohmann LSL hens was flatter than that of Lohmann
brown hens, both curves did not achieve a maximum even at 830 mg dig. Lys intake/hen/d which
Amino Acid Recommendations for laying hens
Figure 6: Body weight gains of ISA brown layers with graded levels of balanced protein intake
(True fecal digestible Lys given as reference) at two energy intakes (Wijtten
et al
.,
2006)
-30.0
-10.0
10.0
30.0
50.0
70.0
90.0
110.0
600 650 700 750 800
TFD Lys intake, mg/d
body weight gain, g
aimed 294 kcal ME/d
aimed 314 kcal ME/d
Vol. 44 (2), Oct. 2009, Page 29
was outside the tested range in the experiment. Interestingly, general diet price did not impact optimal
dietary amino acid levels. Stronger feed price changes per unit balanced dietary protein would reduce
the economically optimal amino acid intake. Also price per kg egg mass influences optimal specifi-
cations.
Our revised recommendation as given in Tables 3 and 4 will allow for maximum egg mass produc-
tion and minimum feed conversion ratio, but not necessarily optimise profitability. Therefore, nutri-
tionists need to fine tune specifications in relation to the economic conditions. However, while the
absolute level of amino acids may change with the economic situation, ideal ratios between the amino
acids remain the same.
Table 4: Recommendations for both digestible amino acid intake of laying hens and in %
of diet for laying hens with differing daily feed intake (Dietary energy reduced: From
11.82 to 11.23 MJ ME/kg)
Amino Acid Recommendations for laying hens
Figure 7: Income over feed cost calculations (IOFC) using experimental data (regression
equations) from Bonekamp
et al.
(2007) and assuming a basal feed price of 1.80
EURO/kg feed, 15.00 EURO/kg egg output, and a feed price increase of 1.00
EURO/100 mg higher dig. Lys (balanced protein) intake.
550 600 650 700 750 800 850 900 950
TFD Lys intake, mg/d
IOFC, rel. scale
Lohmann LSL
Lohmann brown
dig.
Lys
dig.
Met
dig.
Met+Cys
dig.
Thr
dig.
Trp
dig.
Arg
dig.
Ile
dig.
Val
optimal ratios to Lys 100 50 91 70 21 104 80 88
Digestible Amino acids in g/kg diet
Feed intake, g/d
Before energy
reduction
After
energy
reduction
80 84 10.13 5.06 9.22 7.09 2.13 10.53 8.10 8.91
85 89 9.53 4.77 8.67 6.67 2.00 9.91 7.63 8.39
90 95 9.00 4.50 8.19 6.30 1.89 9.36 7.20 7.92
95 100 8.53 4.26 7.76 5.97 1.79 8.87 6.82 7.51
100 105 8.10 4.05 7.37 5.67 1.70 8.43 6.48 7.13
105 110 7.72 3.86 7.02 5.40 1.62 8.02 6.17 6.79
110 116 7.37 3.68 6.70 5.16 1.55 7.66 5.89 6.48
115 121 7.05 3.52 6.41 4.93 1.48 7.33 5.64 6.20
120 126 6.75 3.38 6.14 4.73 1.42 7.02 5.40 5.94
Vol. 44 (2), Oct. 2009, Page 30
Use of supplemental amino acids helps to balance dietary amino acid profile
The principle of least cost feed formulation is that a number of constraints need to be matched by a
suitable combination of ingredients allowing for the most economical solution. Amino acids are provided
either in form of proteins which are found in cereals, legumes, by-products from food oil production,
animal by products etc. or as free amino acids. Currently, DL-Met, L-Lys sources, L-Thr, and L-Trp
are commercially available as amino acids. However, based on the analysis of several hundred
samples of layer feed, often only DL-Met is used. However, the inclusion of the other amino acids
can help reduce dietary protein as well as feed costs.
Amino Acid Recommendations for laying hens
INGREDIENTS Met Met, Lys Met, Lys, Thr Met, Lys, Thr, Trp
Corn 59.863 61.418 61.822 62.538
SBM (46 %) 26.410 25.076 24.727 24.104
Feather meal 2.000 2.000 2.000 2.000
Soy oil 1.297 1.018 0.945 0.813
L-Lys HCl - 0.039 0.049 0.067
DL-Met 0.230 0.240 0.243 0.247
L-Thr - - 0.004 0.012
L-Trp - - - 0.003
Limestone 8.352 8.355 8.356 8.358
Ca
2
P
1.247 1.254 1.255 1.258
Salt 0.400 0.400 0.400 0.400
Premix 0.200 0.200 0.200 0.200
TOTAL 100.00 100.00 100.00 100.00
Cost (RMB/kg) 2.7759 2.7305 2.7193 2.7102
NUTRIENTS AND ENERGY
Energy, kcal ME/kg 2,800 2,800 2,800 2,800
CP, % 18.99 18.55 18.44 18.24
Dig. Lys, % 0.83 0.83 0.83 0.83 0.83
RATIOS TO DIGESTIBLE LYSINE
Specification
Dig. Lys 100 100 100 100 100
Dig. Met 50 58 59 59 59
Dig. Met+Cys 91 91 91 91 91
Dig. Thr 70 72 70 70 70
Dig. Trp 21 22 21 21 21
Dig. Arg 104 135 130 129 127
Dig. Ile 80 84 82 81 80
Dig. Val 88 95 93 92 91
Table 5: Diet formulations for laying hens using revised amino acid specifications and using
DL-Met, DL-Met and L-Lys HCl, DL-Met and L-Lys HCl and L-Thr or DL-Met, L-Lys
HCl, L-Thr and L-Trp (Protein limiting amino acids are marked with grey cells)
Vol. 44 (2), Oct. 2009, Page 31
In Table 5, corn-soybean meal diets with feather meal were formulated using the amino acid specifi-
cations obtained from Table 3 and Chinese raw material prices from December 2007. In diet 1 only DL-
Met was made available to least cost formulation, whereas in diet 2, DL-Met and L-Lys HCl were
made available. In diets 3 and 4, L-Thr and L-Trp also were offered.
In this exercise, the use of the other amino acids beyond DL-Met decreased the use of SBM and
increased the inclusion level of corn. As such, dietary protein level was decreased stepwise as these
other amino acids were made available. The use of these other amino acids allowed the diet to better
match the specified constraints. This is an important effect from an environmental standpoint, because
any reduction in dietary protein level reduces nitrogen excretion. Furthermore, these amino acids (L-
Lys, L-Thr or L-Trp) did not have to be forced into these diets, suggesting that they were needed to
minimise feed cost. Consequently, feed costs were gradually reduced from diet 1 to diet 4. These
examples clearly demonstrate that the use of supplemental amino acids allow for minimising feed
prices, and for better balancing the dietary amino acid profile.
Summary
• Latest scientific research was considered in revising amino acid recommendations for laying hens.
• Considering that methionine is the first limiting amino acid in laying hen diets, a meta-analysis
revealed an optimal digestible methionine intake of 415 mg/hen/d.
• Literature suggested optimal digestible methionine, methionine+cysteine, threonine, tryptophan,
arginine, isoleucine and valine to digestible lysine ratios of 50, 91, 70, 21, 104, 80 and 88 %,
respectively.
• If dietary metabolisable energy needs to be reduced, then essential amino acids also should be
reduced, but to a lesser extent.
• Optimising the dietary amino acid profile and feed cost reduction can only be achieved with the
complete set of commercially available amino acids.
Zusammenfassung
Aminosäurenempfehlungen für Legehennen
• Neueste wissenschaftliche Forschungen wurden bei der Revision der Aminosäurenempfehlungen
für Legehennen in Betracht gezogen. Berücksichtigt man, dass Methionin die erstlimitierende
Aminosäure bei Legehennen ist, so hat eine Meta-Analyse gezeigt, dass die optimale Aufnahme
an verdaulichem Methionin bei 415 mg pro Henne und Tag liegt.
• In der Literatur wurden optimale verdauliche Verhältnisse von Methionin, Methionin+Cystin, Threonin,
Tryptophan, Arginin, Isoleucin und Valin zu verdaulichem Lysin von 50, 91, 70, 21, 104, 80
beziehungsweise 88 % vorgeschlagen.
• Wenn die metabolisierbare Energie im Futter reduziert werden muss, dann sollten die essentiellen
Aminosäuren ebenfalls reduziert werden, wenn auch in einem geringeren Ausmaß.
• Eine Optimierung des Aminosäurenprofils der Diät und eine Reduzierung der Futtermittelkosten
kann nur über den kompletten Satz kommerziell verfügbarer Aminosäuren erreicht werden.
References
Bonekamp, R.P.R.T., A. Lemme, P.J.A. Wijtten, and J.K.W.M. Sparla (2007): Effects of amino acids on egg number and
egg mass of brown (heavy) and whithe (light) hens. 16
th
European Symposium on Poultry Nutrition, August 26-30,
Strasbourg, France: 113-116.
Bregendahl, K., S.A. Roberts, B. Kerr, and D. Hoehler (2008): Ideal ratios of isoleucine, methionine, methionine plus cysteine,
threonine, tryptophan and valine relative to lysine for white Leghorn-type laying hens of twenty-eight to thirty-four weeks
of age. Poultry Science 87: 744-758.
Amino Acid Recommendations for laying hens
Vol. 44 (2), Oct. 2009, Page 32
Coon, C. and B. Zhang (1999): Ideal amino acid profile for layers examined. Feedstuffs 71 (14): 13-15+31.
Elliot, M.A. (2008): Amino acid nutrition of commercial pullets and layers, California Animal Nutrition Conference, May 21-
22, Fresno, California: 139-165.
GfE (Gesellschaft für Ernährungsphysiologie) (1999): Empfehlungen zur Energie- und Nährstoffversorgung der Legehennen
und Masthühner. DLG Verlag, Frankfurt a. Main, Germany: 185.
Jais, C., F.X. Roth, and M. Kirchgessner (1995): The determination of the optimum ratio between the essential amino acids
in laying hen diets. Archiv für Geflügelkunde 59: 292-302.
Joly, P. (2007): Re-evaluation of amino acids requirements for laying hens Part 1: Methionine and cystine requirements.
ISA Hendix Genetics: 13.
Leeson, S. and J.D. Summers (2005): Commercial Poultry Nutrition – 3rd edition. University Books, Ontario, Canada: 398.
Lemme, A. (2007): How to adjust dietary amino acids to energy in broiler diets? AminoNews™ 8 (2): 13-24.
Morris, T.R. (2004): Nutrition of chicks and layers, World’s Poultry Science Journal 60: 5-18.
Rostagno, H.S. (2005): Brazilian Tables for Poultry and Swine - 2
nd
edition. Federal University Vicosa: 181.
Wijtten, P.J.A., A., Lemme, J. van Wichen, J.K.W.M. Sparla, D.J. Langhout, (2006): Amino acid requirements in laying
hens at different energy intakes. 12
th
European Poultry Conference, August 10-14, Verona, Italy: 5.
META-ANALYSIS
Bateman, A., Z. Liu, and D.A. Roland Sr. (2005): Bioefficiency determination of methionine hydroxy analog-free acid relative
to DL-methionine in laying hen diets with limited methionine using different regression models. International Journal of Poultry
Science 4: 628-632.
Bertram, H.-L., J.B. Schutte, and J. de Jong (1995a): Influence of DL-methionine supplements on the performance of laying
hens under heat stress. Archive für Geflügelkunde 59: 314-318.
Bertram H.-L., E. Dänner, K. Jeroch, and H. Jeroch (1995b): Effect of DL-methionine in a cereal-pea diet on the performance
of brown laying hens. Archiv für Geflügelkunde 59: 103-107.
Calderon, W.M., and L.S. Jensen (1990): The requirement for sulphur amino acid by laying hens as influenced by the protein
concentration. Poultry Science 69: 934-944.
Dänner, E.E. and Bessei, W. (2002): Effectiveness of liquid DL-methionine hydroxyl analogue-free acid (DL-MHA-FA)
compared to DL-methionine on performance of laying hens. Archiv für Geflügelkunde 66: 97-101.
Filho, J.J., J.H. Vilar da Silva, E. Lindolfo da Silva, M.L. Gomes Ribeiro, T.D. Dantas Martins, and C. Boa-Viagem Rabello
(2006): Methionine+Cystine requirements of semi-heavy laying hens from the starter to peak of egg production. Rivista
Brasileira de Zootecnia 35: 1063-1069 (supl.).
Fuente Martinez, B., A. Diaz Cruz, J. Lecumberri Lopez, and E. Ávila González (2005): Digestible lysine and sulfur amino
acids requirements in white leghorn hens. Veterinaria México 36 (2): 135-145.
Lemme, A., H.S. Rostagno, A. Knox and A. Petri, (2004): Responses of laying hens to graded levels of dietary methionine.
22
nd
World’s Poultry Congress, June 8-13, Istanbul, Turkey: 4.
Mack, S., D. Hoehler and E. Esteve-Garcia (1999): Responses to methionine supplementation of different white egg-type
laying hen strains under heat stress. 12
th
European Symposium on Poultry Nutrition, August 15-19, Veldhoven, Netherlands.
Narváez-Solarte, W., H.S. Rostagno, P.R. Soares, M.A. Silva, and L.F. Uribe Velasquez, (2005): Nutritional requirements
in methionine+cystine for white-egg laying hens during the first cycle of production. International Journal of Poultry
Science 4: 965-968.
Narváez-Solarte, W. (1996) in: H.S.Rostagno, P. Barbarino Jr., and W.A. Barboza, Nutrient requirements of poultry
determined in Brazil, International Symposium on Nutritional Requirements of Poultry and Swine, September 24-26,
Vicosa, Brazil: 81-107.
Novak, C., H. Yakout and S. Scheideler (2004): The combined effects of dietary lysine and total sulphur amino acid level on
egg production parameters and egg components in Dekalb Delta laying hens. Poultry Science 83: 977-984.
Schutte, J.B., J. de Jong, , and H.L. Bertram (1994): Requirement of the laying hen for sulphur amino acids. Poultry Science
73: 274-280.
Author's Address:
Dr Andreas Lemme
Evonik Degussa GmbH Bldg 251/112
Rodenbacher Chaussee 4 63457 Hanau-Wolfgang, Germany
andreas.lemme@evonik.com
Amino Acid Recommendations for laying hens