II SIMPÓSIO DE AVICULTURA DO NORDESTE

Transcrição

26 a 28 de março de 2014 I Hotel Ouro Branco - João Pessoa, PB
“A avicultura cresce, o Nordeste aparece!”
AMINO ACID CONSIDERATIONS FOR MODERN BROILERS
Paul B. Tillman, Ph.D.¹, William A. Dozier, III, Ph.D.²
¹Poultry Technical Nutrition Services LLC
5813 Bayside Court
Buford, GA 30518-7015
² Professor
Department of Poultry Science
Auburn University
Auburn, AL 36849
Introduction
Digestible amino acids and ratios to lysine are used extensively in formulating diets
for poultry (broilers, layers, turkeys, ducks, quail, etc.) on a global basis. Amino acid use has
and will continue to increase in the coming decades, especially as high priced ingredients,
more limited resources and the environmental impact of excessive dietary nitrogen come
more into consideration through life-cycle assessments (McGill et al., 2012, Kidd et al.,
2013). The digestible lysine (dLys) level of the diet, for each stage of production, is critical in
setting the minimums for the other essential digestible amino acids, as they are defined as
ratios relative to dLys. This formulation method is widely employed as it simplifies the leastcost process since a change in overall amino acid density only requires an alteration in the
dLys level. An increase or decrease in amino acid density is often employed when significant
changes are observed in either feed and/or meat prices; however, having a sound scientific
basis for the degree of change in dLys, versus just an arbitrary adjustment, is critical in order
to maximize profitability.
As high priced ingredients, more limited resources and the
environmental impact of excessive dietary nitrogen
Several
review papers, covering recent broiler amino acid research have been
published (Tillman, 2011a, Tillman, 2012 and Tillman and Dozier, 2013). This paper, which
is the 4th consecutive update on this topic, includes a thorough bibliography and set of tables,
and picks up from the previous three papers by providing an updated review of digestible
amino acid requirements and ratios to dLys through inclusion of the most recently published
or presented information.
Some additional emphasis will be placed upon digestible
methionine (dMet) and digestible sulphur amino acids (dSAA: digestible methionine plus
digestible cysteine) as they were not covered in the first two review(s). Recent research on
the other key essential digestible amino acids, which have the potential to be most deficient in
typical broiler diets: Lysine, Threonine (dThr), Valine (dVal), Isoleucine (dIle), Tryptophan
(dTrp) and Arginine (dArg) will be updated. Then, in summary some economic concepts for
optimizing the dLys level for maximum profitability will be discussed.
Digestible Lysine Requirements
Sriperm (2011a,b) evaluated the dLys level which would maximize bird performance,
as well as the use of various models using the dLys level which would maximize economic
return and profitability. The profitability portion of this will be discussed in more detail in the
economic section towards the end of this paper. A central composite rotatable design was
employed evaluating a titration of the dLys level during the grower (15-35d) as well as the
finisher (early:35-42d or late:35-49d) phase. It was noted that during the grower phase, the
dLys level which maximized bodyweight gain, feed conversion and either breast meat weight
or yield were, 1.126, 1.388 and 1.135%, respectively, averaging 1.196%. During the 15-42d
growout, which encompassed both the grower and early finisher periods, the optimal dLys
levels for the grower and early finisher respectively were : 1.113 & 0.996% for bodyweight
gain, 1.125 & 0.997% for liveweight, 1.135 & 0.994% for carcass weight, 1.182 & 0.981%
for breast meat weight and 1.404 & 0.920% for breast meat yield. On average, these were
1.192% during the grower phase and 0.978% during the early finisher phase to day 42. For
the longer growout (15-49d), encompassing both the grower and late finisher periods, the
optimal dLys levels for the grower and late finisher respectively were: 1.081 & 0.972% for
bodyweight gain, 1.098 & 0.992% for liveweight, 1.094 & 0.988% for carcass weight, 1.094
& 0.995% for breast meat weight and 1.089 & 1.004% for breast meat yield. On average,
these were 1.091% during the grower phase and 0.990% during the late finisher phase to day
49. It should be noted that the average dLys level for the grower and early finisher (35-42d)
phases were 1.192% and 0.978%, respectively; however, the average dLys level for the
grower and late finisher (35-49d) phases were 1.091%and 0.990%, respectively. The longer
grow out decreased the optimal dLys level during the grower (15-35d) phase, but increased
the optimal dLys level during the finisher phase, despite the birds grown for an additional 7
days. In conclusion, it was noted that the dLys which maximized performance (growth and
processing) depended to some degree upon the length of the growout period.
Dozier and Payne (2012) determined the dLys requirement of broilers from 1 to 15
days of age in two experiments. The first trial, during October of 2009, used 1,600 Ross x
Ross 708 females and the second trial, during September of 2010, used Hubbard x Cobb 500
female broilers. Corn, soybean meal, peanut meal (10.14%) and poultry by-product meal
(5%) diets were fed. Digestible lysine was titrated in each trial from 0.95% to 1.43% in
0.08% increments, so as to create 7 treatment diets. In experiment 1, using quadratic brokenline analysis, the dLys requirement, from 1 to 7 days of age, was shown to be 1.352 and 1.383
for bodyweight gain and feed conversion, respectively. In experiment 2, also using quadratic
broken-line analysis, the dLys requirement, from 1 to 7 days of age, was shown to be 1.265
for bodyweight gain. Analysis of the dLys requirement from 1 to 14 days of age in trial 1
indicated a quadratic broken-line breakpoint at 1.27 for bodyweight gain; whereas in trial 2, it
was shown to be 1.18 for bodyweight gain and 1.261 for feed conversion. It was concluded
that these requirement estimates were higher than previous recommendations and research
attributable to some degree to the improved feed conversion of these birds.
Nasr & Kheiri (2012) in a 2x3 factorial design with 2 means of formulation (using
total versus digestible amino acids) and with 3 planes of Lys nutrition (-10% of NRC, NRC
and +10% of NRC). Male broilers from 1-42d were used across 30 floor pens, providing 6
replicates per treatment. It was noted that diets based upon digestible amino acids had
significantly greater breast percentage versus the alternative method of formulation.
In
addition, the higher plane of Lys nutrition also yielded both greater carcass (+4.4%) and
breast (+1.81%) percentages than the diets with lower levels of Lys. The diet with the
highest dLys level provided significantly higher carcass, breast and thigh weights versus the
other 9 treatments.
Oliveira et al. (2013) reported on the lysine requirement of 8 to 21 day of age broilers
using an all-vegetable Corn-Soybean meal based diet. A 5x2 factorial design was used with
five levels of dLys and 2 methods of formulating (only using Corn, soybean Meal and added
methionine (CSM) versus balancing with numerous industrial amino acids (IAA)). Typical
responses to graded levels of dLys were noted for lysine intake, body weight gain, fat
deposition, feed conversion and protein deposition. In the CSM and IAA diets, the dLys
levels of 1.30 & 1.40% were deemed to provide optimum performance, respectively. The
CSM diet estimate of 1.30% for the optimum dLys for bodyweight gain was determined using
the quadratic maximum, whereas feed conversion optimum was determined to be 1.28% using
the linear broken-line model. The IAA estimate for dLys was really not determinable using
any break-point analysis and the reported 1.40% estimate was based upon the highest level
actually fed – as the response was essentially linear.
Siqueira et al. (2013) examined the dLys requirement of Cobb 500 male broilers from
1-8d and 8-22d using either the diet dilution or the diet supplementation method. A 5x2
factorial design was used with five points of dLys and the two formulation methods noted
above. Six replicates were used for each point with each replicate pen having 20 birds each.
In the starter (1-8d) phase, dLys levels from 0.975 to 1.403 were used, incremented by 0.107.
In the grower (8-22d) phase, dLys levels from 0.840 to 1.208 were used, incremented by
0.092. Using the feed conversion response from the diet dilution technique, which was
viewed as superior to the diet supplementation approach, the estimated dLys requirements
determined as the quadratic maximum were reported to be 1.361 and 1.187, for the two
phases respectively.
Digestible
Methionine
Requirements
and
dMet/dLys
Ideal
Ratio
Recommendations and Digestible Methionine+Cysteine Requirements and dSAA/dLys
Ideal Ratio Recommendations
Methionine is the first limiting amino acid for broilers fed corn-soybean meal diets
and sulfur amino acids are used for lean tissue accretion, feather formation, and methyl
donation (Garcia and Batal. 2005). Sulfur amino acid (SAA) requirements of broilers have
been estimated from 0 to 3 weeks of age (National Research Council. 1994; Lumpkins et al.,
2007), but data are limited with digestible SAA (dSAA) to Lys ratios for the starting chick.
The dSAA to Lys ratio has been reported as 72 from 8 to 22 d of age (Baker and Han, 1994)
while Knowles and Southern (1998) reported the dSAA to Lys ratio at 66 and 63 for BW gain
and feed efficiency.
Kalinowski et. al. (2003) reported that the total methionine requirement in 0 to 3 week
old broiler chicks was 0.50%, regardless as to whether they were slow or fast feathering
strains. However, it was noted that the Cysteine requirement was 0.39% for slow-feathering
males versus 0.44% for fast-feathering males.
These values would predict a SAA
requirement of between 0.89% and 0.94% for the 0 to 3 week of age broiler, depending upon
feathering rate.
Rubin et al. (2007) examined the effects of both methionine and arginine dietary levels
on the immunity of broiler chickens submitted to immunological stimuli. They noted that
Met has four primary functions: 1) protein synthesis, 2) glutathione precursor, 3) synthesis of
polyamines and 4) methyl donation.
Bunchasak (2009) wrote a review on the role of Met in poultry production. It was
noted that Met supplementation improves the immune response through both direct and
indirect effects. Direct effects were noted as protein synthesis while indirect effects were
noted through compounds produced from methionine, such as homocysteine, glutathione and
taurine. As such, methionine deficiency can lead to both humoral and nonspecific cellular
immunocompetencies. It was noted relative to the requirement that it is higher than the NRC
(1994), decreases with age, but increases with age when expressed as a ratio to lysine.
Geraert and Mercier (2010) discussed the role of amino acids beyond those of protein
synthesis. In their discussion, two of the areas which were highlighted were immunity and
antioxidant activity, particularly the role of Met and SAA in these areas. Methionine had
been shown to improve the immune status of birds via increased antibody production. It was
also noted that the conversion of methionine into either glutathione or taurine were both cited
as having positive impacts upon reducing oxidative stress.
Goulart et al. (2011) reported on the dSAA ratio of Cobb male broilers from 1 to 42
days of age. Four phases were evaluated: pre-starter (1-7d), starter (8-21d), grower (22-35d)
and finisher (36-42d). It was determined that the dSAA requirement was 0.873%, 0.755%,
0.748% and 0.661%, corresponding to dSAA/dLys ratios of 71, 70, 76 and 72%.
In a recent study, Dozier et al. (2013a) and Dozier and Mercier (2013) examined the
dSAA ratio to Lys in Hubbard × Cobb male broilers from 1 to 14 days of age. Eight
concentrations of dSAA/dLys were fed ranging from 0.56 to 0.86% in increments of 0.06%.
Diets were formulated to contain 1.16% dLys. Digestible SAA/dLys ratio was determined to
be 78 and 77 from 1 to 7 and 1 to 14 days of age, which is higher than requirements estimated
from previous research.
Rostagno et al. (2011) has reported a dSAA to Lys ratio of 72 for 1 to 21 day old
broilers.
Research conducted with the modern broiler having market weights from 2.0 to 3.0 kg
is sparse (Baker at al., 1996). Furthermore, these studies determined an absolute requirement
and not the total SAA ratio to Lys. The dSAA to Lys ratio has been reported as 75 from 20 to
40 days of age (Mack et al., 1999). Moreover, Rostagno et al. (2011) estimated the dSAA to
Lys ratio as 73 for 21 to 56 day old broilers.
Mehri et. al. (2012) examined the ideal ratios for both methionine and threonine to
lysine, of Ross x Ross 308 male broiler chicks, from day 3 to day 16. Response surface
methodology was employed using a central composite rotatable design. Bodyweight gain was
maximized when dLys was 1.12% and dMet was 0.54%, corresponding to a dMet/dLys ratio
of 48. Similar requirement optimums were noted for feed conversion with dLys at 1.13% and
dMet at 0.53%, corresponding to ideal ratios for dMet/dLys of 47.
Dozier et al. (2013b) examined the dSAA to Lys ratio of Ross × Ross 708 male
broilers from 42 to 56 days of age. Broilers were fed 9 experimental diets consisting of 8
concentrations of dSAA/dLys ratios ranging from 0.60 to 0.88 in increments of 0.04. A
standardized Lys digestibility assay was conducted with broiler chicks to determine amino
acid digestibility of the basal diet. Standardized dSAA of the basal diet was determined to be
0.53%. Progressive additions of dSAA/dLys resulted in a significant linear effects for breast
meat weight (P = 0.057) and yield (P = 0.035), but no treatment differences were observed for
growth performance. Digestible SAA/dLys ratios were estimated at 76 and 74 for total breast
meat weight and yield. These data indicated that dSAA/dLys ratios for modern broilers are
higher for total breast meat yield than growth performance.
Digestible
Threonine
Requirements
and
dThr/dLys
Ideal
Ratio
Recommendations
Brito et al. (2013) reported on the dTHR requirement in 1-7d and 8-21d of age male
and female (straight-run) Ross 508 broilers. For bodyweight gain during the 1-7d phase,
using either the linear broken line (LBL) or the Quadratic maximum (Qmax) model, the dThr
requirement estimate was 0.77 and 0.79%, respectively.
During the 8-21d phase, the
estimated dThr requirements were 0.67 and 0.71% from the LBL and Qmax models,
respectively. Other variables measured did not exhibit a significant response to increasing
levels of dThr. While the LB model gave lower error terms, it is generally considered that this
model under-estimates the requirement (Morris, 1983).
From the published paper by Mehri et. al. (2012) noted above, both the ideal ratios for
methionine and threonine to lysine were examined in 3 to 16 day old broilers. Bodyweight
gain was maximized when dLys was 1.12% and dThr was 0.78%, corresponding to a
dThr/dLys ratio of 70. Similar requirement optimums were noted for feed conversion with
dLys at 1.13% and dThr at 0.75% of the diet, corresponding to an ideal ratio of dThr/dLys of
66.
Star et. al. (2012) looking at the threonine requirement of Ross 308 male broiler
chickens from either day 9 to 20 or day 9 to 27 in three experiments. A subclinical infection
model was employed at days 9 and 14 by inoculation with Eimeria maxima and Clostridium
perfringens. While lesion incidence, lesion severity or mortality were not impacted by the
dThr/dLys ratio, there were responses noted in body weight gain and feed intake with
increased dThr/dLys ratios of 69 and 67, respectively. It was also noted in trial 3 that infected
birds had improved bodyweight gain and feed intake when provided a dThr/dLys ratio of 67
versus one of only 63, which was also noted to carry-over out to day 37. It was concluded
that while an increased dThr/dLys ratio did not improve intestinal damage from a subclinical
E. maxima and C. perfringens inoculation, there were noted improvements in bodyweight
gain and feed intake.
In addition, linear broken-line analysis of gain per feed from
experiments 1 & 2 generated a break-point at a 68 dThr/dLys ratio.
Duarte et al. (2012) examined the dThr requirement of 22 to 42 day of age male Cobb
broilers. Six dThr levels were used and a level of dThr of 0.7642% was determined to be the
requirement using a linear broken line model. It should be noted that while dThr/dLys ratio
of 71.19 was reported, this trial design was not setup to determine a ratio. The dLYS level
used, of 1.0735% was essentially at or above the requirement for these 22-42d old broilers
and it is imperative in ratio work that the dLys level be set below the requirement.
Mejia et al. (2012a) evaluated the dThr/dLys ratio of Ross 708 male broilers from 3549 days of age, using simultaneous dLys and dThr titrations. A range from 0.70% to 1.15%
for dLys and of 0.40% to 0.85% for dThr were used in the determination of the optimal ratio.
For BW gain, optimal dLys was 1.09% and optimal dThr was 0.72%, yielding a dThr/dLys
ratio of 66. Absolute requirements for dThr were shown to be 0.67%, 0.72% and 0.74% for
feed consumption, FC and breast meat weight, respectively. The dThr for maximum breast
weight, put against the dLys for maximum bodyweight gain would yield a 68 ratio for
dThr/dLys.
Meloche et al, (2013) presented on the dThr/dLys ratio in 1-14 days of age Hubbard x
Cobb 500 male broilers. Eight titration diets were used with dThr as a % of the diet ranging
from 0.62 to 0.86%. The dLys level of the treatment diets was set below the requirement at
1.13% and each treatment was replicated across 8 pens. The titration of the dThr/dLys ratio
ranged from 55 to 76. Linear broken line analysis was used as an estimate of the optimal
ratio, although it is known that this is not ideal for representing a population and tends to
underestimate the requirement. The optimal dThr/dLys ratio was determined to be 70 and 68
for bodyweight gain and feed conversion, respectively. It was concluded that a minimum
ratio of 68 was required.
Wecke & Liebert (2013) published in the open access, non-peer reviewed journal on a
new, although yet un-validated approach to determining individual amino acid ratios. The
need for further validation of this approach was noted by Pastor et al. (2013). Using nitrogen
balance experiments, along with nitrogen deposition and retention determinants, the slope
(also noted as the efficiency parameter) of a linear line from a control diet (adequate in all
amino acid levels) was used against the slope of a linear line from a diluted diet (deficient in
the test amino acid) as a means of calculating a ratio. Three trials, using thirty-five birds in
each were raised in metabolism cages with either 5 or 7 birds per experimental diet. Two
ages were examined (11-21d) and (25-35d) for total amino acid ratios for Thr, Trp, Arg, Ile
and Val. Several data points were omitted from the final conclusion based upon the slope of
the nitrogen retention curve being non-significant and an average across the three trials were
reported, sometimes being represented by only one trial. Reported total amino acid ratios for
Trp (19 & 17) and Arg (105) were somewhat similar to those reported in the literature for
digestible ratios while the reported ratios for Thr, Ile and Val, tended to be significantly lower
than those reported digestible ratios. It should be noted however that a comparison between
total and digestible ratio can be difficult to make.
Jiang et al. (2014) reported on the dThr/dLys ratio for Hubbard M99 x Cobb 500 male
broilers from 21 to 35 days of age. Eight titration diets were used with dThr as a % of the diet
ranging from 0.49 to 0.77%. The dLys level of the treatment diets was set below the
requirement at 0.95% and each treatment was replicated across 8 pens. The titration of the
dThr/dLys ratio ranged from 51.2 to 80.6. Quadratic broken line analysis was used to
estimate the optimal dThr/dLys ratio and it was determined to be 68 and 67 for bodyweight
gain and feed conversion, respectively.
It was concluded that this study pointed to the
dThr/dLys ratio being higher than previously published for the particular age range evaluated.
Digestible Valine Requirements and dVal/dLys Ideal Ratio Recommendations
Corzo et al. (2010) examined requirement estimates for dVal and dIle in corn, SBM,
meat & bone meal based diets fed to Ross TP16 male broilers from day 28 to day 42. A PC
diet was formulated to be adequate in all nutrients, while a negative control diet was
formulated to be deficient in both dVal and dIle. The control diets were formulated at 0.99%
dLys with the PC having 0.75% dVal and 0.66% dIle and the negative control (NC) diets
being 0.10% points lower for both of these AA. This in effect dropped the ratio of dVal/dLys
from 75 to 65 and that of dIle/dLys from 66 to 56 across the two control diets. Six additional
treatment diets were created by adding L-Val and/or L-Ile back to the NC diet such that either
50% or 100% of the differences for dVal and/or dIle were recovered. There was a significant
decline in performance in both BW gain and feed intake when the dVal and dIle levels were
decreased from the PC to NC diets. Bodyweight was recoverable when either L-Val alone or
in combination with L-Ile were added back to the negative control diet. Feed conversion
required both added L-Val and added L-Ile to show improvement. As had been reported
before, breast meat yield responded to supplemental L-Ile (Kidd et al., 2000). It was deemed
that in these diets, containing meat & bone meal, that live performance responded more to
dVal and was fourth limiting; whereas dIle supplementation increased breast meat yield more.
As such, a scenario of co-limitation likely existed between these two essential AA in regards
to optimizing growth and meat yield.
Corzo et al. (2011) reported on a practical trial designed to evaluate the inclusion of LVal in diets fed to Ross TP16 broilers from 28 to 42 days of age. Two control diets were
formulated to meet all nutrient requirements. A positive control (PC) diet contained added
DL-Methionine, L-Lys HCl and L-Thr and served as the dilution diet in the dVal titration,
while an industry control (IC) diet contained these AA plus L-Val at 0.034% and represented
a potential diet of the future. A summit diet was formulated using 0.13% added L-Val and
was blended in various proportions with the PC diet to make four intermediate titration diets,
with added L-Val in increments of 0.026%. The summit diet was formulated to maintain a 78
ratio between dVal and dLys, while allowing the ratios on dIle, dArg and dTrp to drop as
SBM was replaced with added L-Val. No differences in performance or processing variables
measured existed between the PC & IC diets, indicating L-Val could be least cost formulated
into a diet at 0.034%, successfully. Results from the titration of L-Val inclusion suggested
that up to 0.052% L-Val is feasible in practical diets without significantly sacrificing bird
performance or processing measurements.
Dozier et al (2012) examined the interactive effects of dVal and dIle to dLys ratios to
male Ross x Ross 708 male broilers from either 28 to 42d of age (trial 1) or from 26 to 40d of
age (trial 2). Trial 1 used 10 experimental diets consisting of a positive control diet (1.0%
dLys) and a 3 x 3 factorial arrangement of dVal/dLys ratio (74, 78 or 82) and dIle/dLys ratio
(63, 68 and 73) ) with a reduced dLys level (0.95%). Trial 2 was similar to Trial 1 in that it
also used a 3 x 3 factorial arrangement of dVal/dLys ratio (74, 78 and 82) and dIle/dLys (62,
67 and 72) at a reduced dLys level (0.92%); however, two control diets were fed – one at the
dLys requirement (1.02%) and the other at a reduced dLys level (0.92%). These were
included to assure that dLys was slightly deficient in the treatments, by comparing the two
controls, as well as to compare back to the treatment diet with similar dLys, dVal and dIle
levels. In experiment one, a slightly significant (p=0.045) dVal/dIle ratio interaction was
noted for feed conversion and mortality. No significant main effects for broiler performance
or carcass characteristics were noted however, indicating that perhaps the 74 dVal/dLys ratio
was adequate. In experiment 2, no interactions were noted and the main effects of dVal ratio
to dLys were significant for bodyweight, bodyweight gain, feed conversion and abdominal fat
which were optimized at a dVal/dLys ratio of 82. Interestingly enough however, was the
response in breast meat yield which was also significant being maximized at the lowest
dVal/dLys ratio.
Tavernari et al, (2013) determined the optimal dVal/dLys ratio in Male Cobb 500 (fast
feathering) broilers between 8 & 21d (Starter) and between 30 and 43d (Finisher) of age.
Appropriately, the dLys level of the all-vegetable based treatment diets was reduced below
the requirement, in this case by 7%. Six titration points of dVal/dLys were used in each of the
phases. In the Starter these ranged from 69 to 84 while in the Finisher phase the ranged from
70 to 85, in both cases being incremented by 3 ratio points. For the Starter phase, the
dVal/dLys ratio for bodyweight gain, using 95% of Qmax and the LBL was shown to be 77
and 79, respectively. The feed conversion ratio was optimized at a dVal/dLys ratio of 75 and
76 using 95% of Qmax and the LBL model, respectively. For the finisher phase, 95% of
Qmax model gave a dVal/dLys ratio of 75and 77, for bodyweight gain and feed conversion,
respectively and 75 and 74, when using the LBL model.
Berres et al. (2011), using male Cobb 500 broilers, studied the dVal requirement, as a
% of the diet from 21 to 42 days of age. An all-vegetable, corn-soybean based diet was used
throughout and seven points on the titration curve were used, with dVal ranging from 0.71 to
0.97%, based upon analysis. The range of dVal levels was achieved through the use of added
L-Val with all other ingredients being kept constant. Results were analysed using 95% of
Qmax as well as the LBL model to determine the dVal requirement and since dLys was set at
1.10%, this was not designed to be a ratio trial although ratios of 77 and 76 were reported for
bodyweight gain and feed conversion. Results from using 95% of the Qmax indicated that the
dVal requirement, as a % of the diet, was 0.85, 0.84 and 0.85% for bodyweight gain, feed
conversion and abdominal fat pad yield, respectively. The LBL model predicted the dVal
requirement for bodyweight gain, feed conversion and abdominal fat pad yield to be 0.82,
0.81 and 0.73, respectively. Other measured variables did not show a significant response to
dVal titration, as often observed for the first three limiting amino acids in broiler feeds (SAA,
LYS and THR).
Campos et al (2012) examined the ideal amino acid ratios for arginine, isoleucine,
valine and tryptophan in male broilers from 7-21 and from 28-40d. The dLYS used for each
phase (1.08 & 0.98%) were set below the requirement while all other nutrients (except for
dVal) were at or above the requirement, since this was a ratio trial. Three points on the curve
were used for the dVal / dLys ratio for the two phases : 70, 75 and 80 and 71.5, 77, 82.5,
respectively. The dVal / dLys ratios used during the 7-21d phase showed linear responses for
bodyweight gain and feed conversion. The optimal dIle / dLys ratio for the 28-40d phase was
deemed to be 76.
From a review of recent publications, it appears evident that dVal is clearly fourth
limiting in all vegetable based broiler feeds with corn and/or wheat as the primary grain
source (Tillman, 2011, Tavernari et al, (2013)).
Digestible Isoleucine Requirements and dIle/dLys Ideal Ratio Recommendations
Dozier et al. (2011) reported on the results from a trial designed identically to Corzo et
al. (2010), except for the use of poultry by-product meal rather than meat and bone meal. The
greatest breast meat responses in weight or yield tended to occur at the highest dIle levels, but
often in conjunction with additional L-Val. It was deemed that in these diets, dIle was likely
fourth limiting, although it was closely followed by dVal, again implying a scenario of colimitation between these two essential AA. These two trials, point to the importance of
setting proper ratios or levels for both dVal and dIle.
Mejia et al. (2011) evaluated the dIle/dLys ratio of Ross 708 male broilers from 28 to
42 days of age. A PC diet was formulated at 1.00% dLys and set to be adequate in all
essential amino acids, including dIle, with a ratio of 67. Two treatment diets were formulated
at 0.95% dLys, which is slightly below the requirement, to have either a dIle/dLys ratio of
57.8 or 74.4, representing the basal and summit titration treatment diets, respectively. These
two dies were blended so as to create 5 intermediate diets across the 7 point titration curve. It
was concluded a ratio of 68.9 was adequate for live performance and that a ratio of 71.7 gave
similar results in regards to breast meat yield as to the PC diet, even though the latter was ~
2.25 percentage points higher in CP. These results support the possibility of there being a
higher dIle/dLys ratio requirement to maximize breast meat responses.
As described in the dVal section above, Dozier et al. (2012) examined the interactive
effects of dVal and dIle in two trials, using Ross x Ross 708 males. In experiment 1, the main
effects indicated that increasing the ratio of dIle to dLys reduced abdominal fat weight while
increasing breast meat yield (at least up to 68). There was no significant impact on broiler
growth parameters from increasing the dIle/dLys ratio in either trial 1 or 2. As in trial 1,
results from trial 2 indicated a significant response to increasing the dIle/dLys ratio in terms
of improving breast meat yield (at least up to 67).
Tavernari et al (2012) evaluated the dIle / dLys ratio in male Cobb 500 broilers from
7-21 and from 30-43 days of age. A titration range from 58 to 75.3, incremented by 3.5
points providing 6 treatment levels. Diets were based upon Corn, soybean meal, corn gluten
meal and spray-dried plasma. Results were reported as linear broken line (break-point),
Qmax (within the Figures) and also as 95% of Qmax and Quadratic broken-line (QBL) (both
within the text). As such, a close reading of the paper is required to fully extract the results.
As the LBL typically underestimates the optimal ratio, I will discuss here the Qmax, 95% of
Qmax and QBL – although the LBL results are also shown in Table 6.
During the 7-21d
period, the following Qmax, 95% of Qmax and QBL values respectively were reported as :
68, 65, 64 for bodyweight gain, 69, 66, 65 for feed conversion, breast weight and breast fillet
weight and 70, 67, 66 for breast yield and breast fillet yield. During the 30-43d period, the
following Qmax, 95% of Qmax and QBL values respectively were reported as : 70, 66, 64 for
feed intake, 72, 68, 68 for bodyweight gain and 75, 72, 72 for feed conversion. It was
concluded overall that the dIle / dLys ratio recommendation was 66 from 7-21d and 68 from
3-43d.
dIle) were at or above the requirement, since this was a ratio trial. Three points on the curve
were used for the dIle / dLys ratio, for the two phases : 60, 65, 70 and 58, 67, 76, respectively.
The dIle / dLys ratios used during the 7-21d phase showed linear responses for bodyweight
gain and feed conversion. The optimal dIle / dLys ratio for the 28-40d phase was deemed to
be 69.
Digestible
Tryptophan
Requirements
and
dTrp/dLys
Ideal
Ratio
Recommendations
Hsia et al. (2005) evaluated the effect of tryptophan on growth and carcass
characteristics in Hubbard male broilers in a series of three trials and across various ages.
Trial 1 was conducted from 35-56d of age, trial 2 from 21-49d of age and trial 3 from 14-42d
of age. Levels of total tryptophan fed in the three trials were: trial 1- 0.198%, 0.228% and
0.258%, trial 2- 0.167% or 0.198% and trial 3- 0.136%, 0.167% and 0.198%. The total
lysine level content was 1.1%, 1.0% and 1.0% for trials 1, 2 and 3, respectively. In trial 1, no
differences were noted between the three treatments for feed intake, bodyweight gain, feed
conversion or carcass characteristics. It was noted in trial 2 feed intake was not different
between the two treatment levels; however bodyweight gain, feed conversion and a few of the
carcass characteristics were significantly different in the high versus low total tryptophan
level fed. In trial 3, the lowest level of tryptophan fed gave the lowest bodyweight gain and
poorest feed conversion. In addition, the lowest total tryptophan level fed also gave the
poorest weights for breast, thigh and heart.
Corzo (2012) evaluated the arginine and tryptophan ideal ratios in Ross x Ross 708
male and female broilers from 1 to 18 days of age. No differences were noted between the
two sexes. For dTrp, five points across the titration curve were used ranging from 10 to 22 in
increments of 3 ratio points. A value of 95% of the quadratic maximum response was used as
the estimate for the ideal ratio. The determined ideal ratios for bodyweight gain, feed intake
and feed conversion were 18, 19 and 17, respectively. On average, the ideal ratio for
dTrp/dLys was 18.
dTrp) were at or above the requirement, since this was a ratio trial. Three points on the curve
were used for the dTrp / dLys ratio, for the two phases : 15, 16, 17 and 14, 17, 20,
respectively. No responses were observed from the dTrp treatments during the 7-21d phase.
The optimal dIle / dLys ratio for the 28-40d phase was deemed to be 76.
The order of limitation for tryptophan and arginine should generally fall after those for
dVal and dIle. The ratio for tryptophan tends to be in the range of 16 to 18 and rarely is a
constraint, even though it should be monitored, particularly in diets containing high levels of
corn plus corn distillers dried grains with solubles.
Digestible Arginine Requirements and dArg/dLys Ideal Ratio Recommendations
As noted above, Corzo (2012) evaluated the arginine and tryptophan ideal ratios in
Ross x Ross 708 straight-run broilers from 1 to 18 days of age. No differences were noted
between the two sexes. For dArg, five points across the titration curve were used ranging
from 75 to 115 in increments of 10 ratio points. As before, a value of 95% of the quadratic
maximum response was used as the estimate for the ideal ratio. The determined ideal ratios
for bodyweight gain, feed intake, feed conversion and livability were 108, 106, 114 and 103,
respectively. On average, the ideal ratio for dArg/dLys was determined to be108.
Mejia et. al. (2012) evaluated the dArg/dLys ratio of male Ross 708 broilers from 28
to 42 days of age during a constant, elevated temperature. Corn, soybean meal, corn distiller
dried grains with solubles, meat & bone meal based diets were used. Digestible arginine was
titrated, using L-Arg, across 7 treatment diets from a ratio of 100 to 130, relative to dLys
which was set below the requirement at 0.95%. Based upon performance and processing
responses, it was determined that the dArg/dLys ratio was no higher than 105. It was
concluded from this paper that dArg typically should not become a formulation constraint
unless sorghum/milo is the primary grain source in the diet. Nonetheless, it is proper and
advisable to set a minimum dArg/dLys ratio of at least 105 and perhaps upwards of 108 in
later phase diets, although it naturally increases across phases.
dArg) were at or above the requirement, since this was a ratio trial. Three points on the curve
were used for the dArg / dLys ratio, for the two phases : 100, 105, 110 and 95, 105, 115,
respectively. No responses were observed from the dTrp treatments during the 7-21d phase.
The dArg / dLys ratios used during the 28-40d phase showed linear responses for bodyweight
gain and feed conversion.
Neto et al. (2013) examined the dArg/dLys ratio in Cobb 500 male broilers from 21 to
42 days of age under high environmental temperature. While they only examined a 105 and
140 ratio of dArg/dLys, they noted that broilers provided the 105 ratio had better live
performance, carcass weights, carcass yields, longer villi length and shallower crypt depths.
In addition, when the birds were innoculated with an antigen, the lower dArg/dLys ratio gave
a better immune response.
Economics
Several papers have addressed the impact of amino acid levels on optimizing
profitability (DeBeer (2009, 2010), Eits et al. (2005 a,b), Lemme (2005), Pack et al. (2003),
Ziggers (2011)). Due to the extensive use of ideal amino acid ratios in formulation, most of
the emphasis has been placed upon the economically optimal dLys level; however, Kidd et al.
(1998) noted the optimal level of dThr which maximized profitability was near the dThr level
which also maximized broiler performance (feed conversion) and processing (carcass
composition) parameters. It is likely that this is the case for all of the essential amino acids –
that feeding near their requirement for performance is also close to the point which maximizes
profitability.
Afterall, improvements in bodyweight gain, feed conversion and carcass
characteristics (particularly breast meat weight and yield) are often noted for several of these
amino acids.
Sriperm (2011a,b) evaluated various models to determine the economically optimal
dLys level which would maximize profitability from selling whole carcass or parts. These
scenarios were evaluated across a wide range of both feed ingredient (dietary) costs as well as
meat (carcass, breast, wings and leg quarters) prices. For example, one example evaluated
Corn at ~$280/ton and Soybean Meal at ~ $385/ton prices, along with the carcass price at ~
$0.64/pound price, the optimal dLys level to maximize profitability was 1.09% during the
grower (15-35d) and 0.90% during the late finisher (35-49d), using a Cobb-Douglas
production function. These values are not dissimilar to those determined from the static :
production approach cited above. If carcass price were higher than that noted above, then the
optimal dLys level for profitability would increase and it was noted that the meat or carcass
price was more of a driver for the optimal profitability than is feed price.
Tillman and Sriperm (2011b) presented a paper looking at the difference between
dLys requirements determined from static : production (growth and feed efficiency) estimates
versus those determined from profitability which also incorporates dynamic : market process
(feed costs and meat prices).
Various prediction models were employed, including the line
intercept of models, the dLys requirement for static : production variables were determined
using an average value from a quadratic broken-line (QBL) model, a quadratic and linear twoslope broken line model, the intercept of the linear broken-line model and quadratic
polynomial model and the intercept of the QBL and quadratic polynomial model. It was
shown that the requirement for Cobb 700 males from 28-42d were 0.95%, 0.99%, 1.00% and
0.97% for bodyweight gain, feed conversion, carcass weight and breast meat weight,
respectively. These average of these static : production dLys requirements was 0.978%.
When dynamic : market assessment of the dLys requirement which optimizes profitability
was determined, across a wide range of feed and meat prices, the results were similar for the
point which was the best case scenario (low feed but high meat prices). For example, the
dLys level which maximized profitability for the carcass at the best case scenario was 0.986%
and that for maximizing profitability from the breast meat was 0.980%.
What was of
particular note however was the worst case scenario for each example, which only reduced the
dLys level for maximum profitability by 0.889% and 0.947% for carcass and breast meat
return, respectively. These differences from best to worst case only decreased the dLys level
for maximum profitability by 0.097 and 0.033 percentage points, respectively. These value
differences are less than what is sometimes done within the broiler industry, based upon what
is “felt” to be the correct decision – thus pointing out the importance of making well informed
decisions when it comes to overall amino acid density of broiler diets.
Abstracts of presentations are available from Perryman et al. (2013, Trial 1) and
Tillman et al. (2013, Trial 2) with Ross x Ross 708 male broilers grown to 42 days of age and
Hubbard M99 x Cobb 500 male broilers grown to 35 days of age, respectively.
Five
treatments were offered ranging from a basal to a summit diets, with intermediates labelled as
industry low, industry high and requirement diets. For the Ross broilers, weighted dLys
levels, based upon dietary dLys level and feed intake, from 0.86% to 1.14% in increments of
0.07 percentage points were fed across the three phases (starter: 1-14, grower: 15-28 and
finisher: 29-42). In both trials, linear responses in carcass weight, carcass yield, breast
weight, breast yield, drumstick weight, wing weight and thigh weight were noted to
increasing dLys levels and intakes. Quadratic responses were also noted for carcass weight,
breast weight and breast yield in trial 1, but only for drumstick, wing and thigh weights in
trial 2. A weighted average dLys level of 1.07%, was determined as the point where return
over feed cost was maximized after 42 days of growth with the Ross 708. For the second
paper presented, using Hubbard M99 x Cobb 500 male broilers, grown to 35 days of age, the
weighted dLys level ranged from 0.88% to 1.16%, again in increments of 0.07 percentage
points. A weighted average dLys level of 1.02%, was determined as the point where return
over feed cost was maximized after 35 days of growth with the Hubbard M99 x Cobb 500
male broiler.
Summary and Conclusions
This paper has strived to provide an update on AA broiler nutrition during the past few years,
with special emphasis on the dLys, dThr, dVal, dIle and dArg requirements and more
particularly the dThr/dLys, dVal/dLys, dIle/dLys and dArg/dLys ratio recommendations.
With the enhancements in growth rates, FC and white meat yields, largely due to genetic
selection, AA requirements have become critical to maximize technical performance while
optimizing economic performance. The ratio on the next limiting AA, which cannot be
supplemented, becomes highly critical in maintaining a proper nitrogen pool from which nonessential amino acids and proteins can be synthesized. Depending upon the ingredients used
and the commercial AA’s economically available, this next limiting AA can vary. Therefore,
special emphasis needs to be placed on setting proper ideal ratios for these potentially limiting
essential AA’s (dVal, dIle, dArg and dTrp) which are also required to optimize broiler
performance and profitability.
NOTE: Abbreviations used within the following tables :
1BW=Bodyweight, BWG=Bodyweight gain, FC=Feed Conversion, FI=Feed Intake,
CW=Carcass Weight, CY=Carcass Yield, BMW=Breast Meat Weight, BMY=Breast Meat
Yield, BFW=Breast Fillet Weight (Pectoralis major),BFY=Breast Fillet Yield, PA=Protein
Accretion, VA=Valine Accretion, AFY =Abdominal Fat Yield.
2LBL=Linear Broken Line, QBL=Quadratic Broken Line, Q=Quadratic, Qmax = Quadratic
Maximum, CCRD=Central Composite Rotatable Design / Response Surface.
3Veg.=Vegetable based diet, ABP=Animal by-Product included in diet, BC = Blood Cells in
the diet.
Table 1. Digestible Lysine Requirements
Reference
Strain
Sex
Age
Dozier &
Payne
(2012)
Ross 708
F
1-7d
Hubbard x
Cobb 500
F
1-14d
1-7d
1-14d
Cobb 500
M
Cobb
M
Siqueira et
al., (2013)
Oliveira et
al. (2013)
Dozier et
al.
(2009a)
Ross TP16 M
F
M
Dozier et
al. (2009b)
Sriperm
(2011)
Dozier et
al. (2010a)
F
Ross TP16 M
Ross 708
M
Ross TP16 M
Cobb 700
M
1-8d
8-22d
8-21d
Parame
ter1
BWG
FCR
BWG
BWG
BWG
FCR
FCR
BWG
FC
14-28d BWG
FC
BWG
FC
BWG
FC
FC
14-28d FC
BWG
FI
FC
BWG
FC
BWG
FC
15-35d BWG
FCR
28-42d BMW&
BMY
BWG
FC
CW
CY
BMW
28-42d BWG
FC
CW
CY
BMW
BMY
dLys
(%)
1.35
1.38
1.27
1.27
1.18
1.26
1.361
1.187
1.30
1.28
1.09
1.15
0.98
0.99
1.07
1.10
1.03
1.18
1.23
1.22
1.20
1.16
1.20
1.18
1.24
1.13
1.39
1.14
0.99
1.05
0.94
0.92
0.96
0.97
1.01
1.03
0.96
0.99
0.98
Method2
Comment
QBL
Qmax
Diet dilution
technique.
Qmax
LBL
QBL
x at 95% of
Qmax
x at 95% of
Qmax
LBL
Humid
x at 95% of
Qmax
LBL
Moderate
QBL
QBL
QBL
Shirley et
al. (2009)
Cobb 500
M&
F
Dimova et
al. (2010)
Hubb
M99xCob
b500
M
35-49d BW
BWG
FC
BFW
BMY
35-49d BWG
FC
BMY
CW
0.95
0.96
1.01
0.98
0.95
0.86
0.91
0.90
1.02
LBL
LBL
Table 2. Digestible Methionine / dLys Ideal Ratio Recommendations
Reference
Mehri et al.
(2012)
Strain
Sex
Age
3-16d
Parameter1
BWG
FCR
dMet/dLys
48
47
Method2
CCRD
Comment3
Method2
Comment3
Table 3. Digestible SAA / dLys Ideal Ratio Recommendations
Reference
Dozier et
al. (2013a)
Rostagno et
al. (2011)
Goulart et
al. (2011)
Dozier et
al. (2013b)
Strain
Hubbard
xCobb500
Sex
M
Cobb
M
Ross708
M
Age
1-7d
1-14d
1-21d
21-56d
1-7d
8-21d
22-35d
36-42d
42-56d
Parameter1
BMW
BMY
dSAA/dLys
78
77
72
73
71
70
76
72
76
74
QBL
Table 4. Digestible Threonine / dLys Ideal Ratio Recommendations
Reference
Strain
Sex
Age
Brito et al.
(2013)
Ross 508
M&F
1-7d
Meloche et
al. (2013)
Hubbard
x Cobb
500
M
1-14d
Ross308
M
3-16d
Ross 508
M&F
8-21d
Ross308
M
9-20d
Mehri et
al. (2012)
Brito et al.
(2013)
Star et al.
(2012)
Paramet
er1
BW
BW
dThr
(%)
0.77
0.79
dThr/dLy
s
BWG
70
FCR
68
BWG
FCR
BW
BW
G/F
0.78
0.75
0.67
0.71
0.69
70
66
68
69
Method
2
Comment3
LBL
Qmax
Not a ratio
trial
LBL
CCRD
LBL
Qmax
LBL
QBL
Not a ratio
trial
Corzo et
al. (2009)
Jiang et al.
(2014)
Duarte et
al. (2012)
Ross
TP16
Hubbard
x Cobb
500
Cobb 500
M
1428d
BWG
FCR
M
2135d
BWG
68
FCR
M
2242d
FCR
67
Reported a
71 ratio
Slope of
N
Retentio
n Curves
General
0.68
68
BWG
FCR
BMW
Growth
Carcass
BWG
FCR
CY
BMW
0.72
0.72
0.75
0.66
0.67
0.68
0.67
0.75
0.70
66
66
68
Wecke &
Liebert
(2013)
Ross 308
M
2535d
Everett et
al. (2010)
Ross
TP16
M
2842d
Mejia et al.
(2012)
Ross708
M
3549d
Kidd
(1999)
Ross x
Hubbard
M
4256d
Dozier et
al (2000)
Ross308
M
4256d
0.73
0.76
0.76
69
70
62
LBL
QBL
LBL
Not a ratio
trial
AA
Efficien
cy
Total AA.
Non-peer
reviewed.
QBL
95% of
Qmax
Table 5. Digestible Valine / dLys Ideal Ratio Recommendations
Parameter1
BWG
FCR
BWG
FCR
Multiple
dVal/dLys
77
75
79
76
68
Method2
x at 95%
of Qmax
LBL
21-42d
BMY
BWG
BFW
BMW
BFW
BMY
72
78
77
77
74
74
x at 95%
of Qmax
Veg.
22-35d
Multiple
76
x at Qmax
Veg.
M
25-35d
79
AA
Efficiency
M
7-21d
Slope of N
Retention
Curves
Multiple
78
x at Qmax
Total AA.
Non-peer
reviewed.
Veg.
Reference
Tavernari et
al. (2013)
Strain
Cobb 500
Sex
M
Age
8-21d
Thornton et
al. (2006)
Corzo et al.
(2007)
Ross 508
M
21-42d
Ross 708
M
Costa et al.
(2010a)
Cobb 500
Wecke &
Liebert
(2013)
Campos et al.
Ross 308
Cobb 500
Comment3
Veg.
ABP
(2009b)
Dozier et al.
(2012)
Campos et al.
(2012)
Tavernari et
al. (2013)
Costa et al.
(2010b)
Ross 708
M
Unknown
M
28-40d
26-40d
28-42d
28-40d
Cobb 500
M
30-43d
Cobb 500
37-41d
Multiple
79
82
74
76
BWG
FCR
BWG
FCR
Multiple
75
77
75
74
>77
95% of
Qmax
x at 95%
of Qmax
LBL
Complex
ABP Diets
Veg.
x at Qmax
Veg.
Table 6. Digestible Isoleucine / dLys Ideal Ratio Recommendations
Reference
Campos et al.
(2009a)
Tavernari et
al. (2012) &
Helmbrecht et
al. (2010)
Strain
Sex
Age
Cobb 500
M
Cobb 500
M
7-21d
28-40d
7-21d
30-43d
Wecke &
Liebert (2013)
Ross 308
M
25-35d
Campos et al.
(2012)
Mejia et al.
(2011)
Dozier et
al.(2012)
Unknown
M
28-40d
Ross 708
M
28-42d
Ross 708
M
26-40d
28-42d
Parameter
1
Multiple
BWG
FC, BMW,
BFW
BMY, BFY
BWG, FC,
BMW,
BMY,
BFW
BFY
BWG
FI
FC
BWG
FI
FC
dIle/
dLys
67
70
68
69
70
62
63
63
62
69
72
70
75
Method2
Comment3
x at Qmax
Qmax. 95%
of value
reported in the
text.
LBL
Slope of N
Retention
Curves
Multiple
65
Qmax. 95%
of value
reported in the
text.
AA Efficiency
69
95% of Qmax
FC
BMY
BMY
69
72
67
68
x at 95% of
Qmax
Veg.
Total AA.
Non-peer
reviewed.
Complex
ABP Diets
ABP
Table 7. Digestible Tryptophan / dLys Ideal Ratio Recommendations
Reference
Wecke & Liebert
(2013)
Strain
Ross
308
Campos et al.
(2012)
Unkno
wn
Corzo (2012)
Ross70
8
Se
x
M
M
M
Age
1121d
2535d
2840d
118d
Parame
ter1
Slope of
N
Retentio
n Curves
Multiple
dTrp/d
Lys
19
BWG
FI
FC
18
19
17
Method2
Comment3
AA
Efficiency
Total AA. Non-peer
reviewed.
95% of
Qmax
Complex ABP Diets
17
18
95% of
Qmax
Table 8. Digestible Arginine / dLys Ideal Ratio Recommendations
Reference
Strain
Sex
Age
Corzo (2012)
Ross7
08
M
&F
1-18d
Wecke & Liebert
(2013)
Neto et al. (2013)
Mejia et
al.(2012)
Ross
308
Cobb5
00
Ross7
08
M
11-21d
&
25-35d
M
21-42d
M
28-42d
Parame
ter1
BWG
FI
FC
Livabilit
y
Slope of
N
Retentio
n
Curves
dArg/d
Lys
108
106
114
Method2
Comment3
95% of Qmax
103
105
AA Efficiency
Total AA. Nonpeer reviewed.
LSD with
=0.05
ABP
105
FC
105
Table 9. Recommendations for Broiler Ideal Digestible Amino Acid Ratios relative to Digestible Lysine
Phase
Pre-Starter
ME (Kcal / Lb)
Start day End day
1
7
Minimum Ratios to Digestible Lysine = dMet/dLys dSAA/dLys dThr/dLys dVal/dLys dIle/dLys dTrp/dLys dArg/dLys
1,370
45
75
70
76
66
16
105
Digestible Lysine (dLys)
dMet
dSAA
dThr
dVal
dIle
dTrp
dArg
1.30%
0.59%
0.98%
0.91%
0.98%
0.86%
0.21%
1.37%
Phase
Starter
ME (Kcal / Kg)
Start day End day
8
14
1,380
45
75
70
76
66
16
105
dMet
dSAA
dThr
dVal
dIle
dTrp
dArg
1.20%
0.54%
0.90%
0.84%
0.90%
0.79%
0.19%
1.26%
Phase
Grower
ME (Kcal / Kg) 1,400
46
76
69
77
67
16
106
Start day End day
dMet
dSAA
dThr
dVal
dIle
dTrp
dArg
15
28
1.10%
0.51%
0.84%
0.76%
0.84%
0.74%
0.18%
1.17%
Phase
Finisher
ME (Kcal / Kg)
Start day End day
29
42
1,425
47
77
68
78
68
16
107
dMet
dSAA
dThr
dVal
dIle
dTrp
dArg
1.00%
0.47%
0.77%
0.68%
0.77%
0.68%
0.16%
1.07%
ME (Kcal / Kg)
Start day End day
Phase
Withdrawal
43
56
1,450
48
78
68
79
69
16
108
dMet
dSAA
dThr
dVal
dIle
dTrp
dArg
0.90%
0.43%
0.70%
0.61%
0.70%
0.62%
0.14%
0.97%
Note: These general recommendations are those of the primary author, based upon the data
presented within this paper. Depending upon ingredient matrix values, local conditions, etc.
these suggested ratios might differ by as much as +/- 2 points.
Bibliography
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