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“A avicultura cresce, o Nordeste aparece!”

II SIMPÓSIO DE AVICULTURA DO NORDESTE

26 a 28 de março de 2014 I Hotel Ouro Branco - João Pessoa, PB

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 least-

cost 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 broken-

line 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 35-

49 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 L-

Val 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 co-

limitation 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 two-

slope 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 non-

essential 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 Parame

ter1

dLys

(%)

Method2 Comment

Dozier &

Payne

(2012)

Ross 708

F 1-7d BWG

FCR

1.35

1.38

QBL

1-14d BWG 1.27

Hubbard x

Cobb 500

F 1-7d BWG 1.27

1-14d BWG

FCR

1.18

1.26

Siqueira et

al., (2013)

Cobb 500 M 1-8d FCR 1.361 Qmax Diet dilution

technique. 8-22d 1.187

Oliveira et

al. (2013)

Cobb M 8-21d BWG 1.30 Qmax

FC 1.28 LBL

Dozier et

al.

(2009a)

Ross TP16 M 14-28d BWG 1.09 QBL

FC 1.15

F BWG 0.98

FC 0.99

M BWG 1.07 x at 95% of

Qmax FC 1.10

F FC 1.03

Dozier et

al. (2009b)

Ross TP16 M 14-28d FC 1.18 x at 95% of

Qmax

Humid

BWG 1.23 LBL

FI 1.22

FC 1.20

BWG 1.16 x at 95% of

Qmax

Moderate

FC 1.20

BWG 1.18 LBL

FC 1.24

Sriperm

(2011)

Ross 708 M 15-35d BWG 1.13 QBL

FCR 1.39

Dozier et

al. (2010a)

Ross TP16 M 28-42d BMW&

BMY

1.14 QBL

BWG 0.99

FC 1.05

CW 0.94

CY 0.92

BMW 0.96

Cobb 700 M 28-42d BWG 0.97 QBL

FC 1.01

CW 1.03

CY 0.96

BMW 0.99

BMY 0.98




Shirley et

al. (2009)

Cobb 500 M&

F

35-49d BW 0.95 LBL

BWG 0.96

FC 1.01

BFW 0.98

BMY 0.95

Dimova et

al. (2010)

Hubb

M99xCob

b500

M 35-49d BWG 0.86 LBL

FC 0.91

BMY 0.90

CW 1.02

Table 2. Digestible Methionine / dLys Ideal Ratio Recommendations

Reference Strain Sex Age Parameter1 dMet/dLys Method

2 Comment

3

Mehri et al.

(2012)

3-16d BWG 48 CCRD

FCR 47

Table 3. Digestible SAA / dLys Ideal Ratio Recommendations

Reference Strain Sex Age Parameter1 dSAA/dLys Method

2 Comment

3

Dozier et

al. (2013a)

Hubbard

xCobb500

M 1-7d 78

1-14d 77

Rostagno et

al. (2011)

1-21d 72

21-56d 73

Goulart et

al. (2011)

Cobb M 1-7d 71 QBL

8-21d 70

22-35d 76

36-42d 72

Dozier et

al. (2013b)

Ross708 M 42-56d BMW 76

BMY 74

Table 4. Digestible Threonine / dLys Ideal Ratio Recommendations

Reference Strain Sex Age Paramet

er1

dThr

(%)

dThr/dLy

s

Method2

Comment3

Brito et al.

(2013) Ross 508 M&F 1-7d

BW 0.77

LBL Not a ratio

trial BW 0.79 Qmax

Meloche et

al. (2013)

Hubbard

x Cobb

500

M 1-14d BWG

70

LBL FCR 68

Mehri et

al. (2012) Ross308 M 3-16d

BWG 0.78 70 CCRD

FCR 0.75 66

Brito et al.

(2013) Ross 508 M&F 8-21d

BW 0.67

LBL Not a ratio

trial BW 0.71 Qmax

Star et al.

(2012) Ross308 M 9-20d

G/F 0.69 68 LBL

69 QBL




Corzo et

al. (2009)

Ross

TP16 M

14-

28d

BWG 0.73 69 LBL

FCR 0.76 70

Jiang et al.

(2014)

Hubbard

x Cobb

500

M 21-

35d

BWG

68 QBL

FCR 67

Duarte et

al. (2012) Cobb 500 M

22-

42d FCR 0.76

Reported a

71 ratio LBL

Not a ratio

trial

Wecke &

Liebert

(2013)

Ross 308 M 25-

35d

Slope of

N

Retentio

n Curves

62

AA

Efficien

cy

Total AA.

Non-peer

reviewed.

Everett et

al. (2010)

Ross

TP16 M

28-

42d General 0.68 68

Mejia et al.

(2012) Ross708 M

35-

49d

BWG 0.72 66

QBL FCR 0.72 66

BMW 0.75 68

Kidd

(1999)

Ross x

Hubbard M

42-

56d

Growth 0.66

95% of

Qmax

Carcass 0.67

Dozier et

al (2000) Ross308 M

42-

56d

BWG 0.68

FCR 0.67

CY 0.75

BMW 0.70

Table 5. Digestible Valine / dLys Ideal Ratio Recommendations

Reference Strain Sex Age Parameter1 dVal/dLys Method

2 Comment

3

Tavernari et

al. (2013)

Cobb 500 M 8-21d BWG 77 x at 95%

of Qmax

Veg.

FCR 75

BWG 79 LBL

FCR 76

Thornton et

al. (2006)

Ross 508 M 21-42d Multiple 68 ABP

Corzo et al.

(2007)

Ross 708 M 21-42d BMY 72 x at 95%

of Qmax

Veg.

BWG 78

BFW 77

BMW 77

BFW 74

BMY 74

Costa et al.

(2010a)

Cobb 500 22-35d Multiple 76 x at Qmax Veg.

Wecke &

Liebert

(2013)

Ross 308 M 25-35d Slope of N

Retention

Curves

79 AA

Efficiency

Total AA.

Non-peer

reviewed.

Campos et al. Cobb 500 M 7-21d Multiple 78 x at Qmax Veg.




(2009b) 28-40d 79

Dozier et al.

(2012)

Ross 708 M 26-40d 82

28-42d 74

Campos et al.

(2012)

Unknown M 28-40d Multiple 76 95% of

Qmax

Complex

ABP Diets

Tavernari et

al. (2013)

Cobb 500 M 30-43d BWG 75 x at 95%

of Qmax

Veg. FCR 77

BWG 75 LBL

FCR 74

Costa et al.

(2010b)

Cobb 500 37-41d Multiple >77 x at Qmax Veg.

Table 6. Digestible Isoleucine / dLys Ideal Ratio Recommendations

Reference Strain Sex Age Parameter

1

dIle/

dLys Method

2 Comment

3

Campos et al.

(2009a)

Cobb 500 M 7-21d Multiple 67 x at Qmax

28-40d 70

Tavernari et

al. (2012) &

Helmbrecht et

al. (2010)

Cobb 500 M

7-21d BWG 68 Qmax. 95%

of value

reported in the

text.

Veg.

FC, BMW,

BFW

69

BMY, BFY 70

BWG, FC,

BMW,

BMY,

BFW

62 LBL

BFY 63

30-43d BWG 63

FI 62

FC 69

BWG 72 Qmax. 95%

of value

reported in the

text.

FI 70

FC 75

Wecke &

Liebert (2013)

Ross 308 M 25-35d Slope of N

Retention

Curves

65 AA Efficiency Total AA.

Non-peer

reviewed.

Campos et al.

(2012)

Unknown M 28-40d Multiple 69 95% of Qmax Complex

ABP Diets

Mejia et al.

(2011)

Ross 708 M 28-42d FC 69 x at 95% of

Qmax

ABP

BMY 72

Dozier et

al.(2012)

Ross 708 M 26-40d BMY

67

28-42d 68




Table 7. Digestible Tryptophan / dLys Ideal Ratio Recommendations

Reference Strain Se

x Age

Parame

ter1

dTrp/d

Lys Method

2 Comment

3

Wecke & Liebert

(2013)

Ross

308

M 11-

21d

Slope of

N

Retentio

n Curves

19 AA

Efficiency

Total AA. Non-peer

reviewed.

25-

35d 17

Campos et al.

(2012)

Unkno

wn

M 28-

40d

Multiple 18 95% of

Qmax

Complex ABP Diets

Corzo (2012) Ross70

8 M

1-

18d

BWG 18 95% of

Qmax FI 19

FC 17

Table 8. Digestible Arginine / dLys Ideal Ratio Recommendations

Reference Strain Sex Age Parame

ter1

dArg/d

Lys Method

2 Comment

3

Corzo (2012) Ross7

08

M

&F 1-18d

BWG 108

95% of Qmax

FI 106

FC 114

Livabilit

y 103

Wecke & Liebert

(2013)

Ross

308 M

11-21d

&

25-35d

Slope of

N

Retentio

n

Curves

105 AA Efficiency Total AA. Non-

peer reviewed.

Neto et al. (2013) Cobb5

00 M 21-42d 105

Mejia et

al.(2012)

Ross7

08 M 28-42d FC 105

LSD with

=0.05 ABP




Table 9. Recommendations for Broiler Ideal Digestible Amino Acid Ratios relative to Digestible Lysine

Minimum Ratios to Digestible Lysine = dMet/dLys dSAA/dLys dThr/dLys dVal/dLys dIle/dLys dTrp/dLys dArg/dLys

ME (Kcal / Lb) 1,370 45 75 70 76 66 16 105

Phase Start day End day Digestible Lysine (dLys) dMet dSAA dThr dVal dIle dTrp dArg

Pre-Starter 1 7 1.30% 0.59% 0.98% 0.91% 0.98% 0.86% 0.21% 1.37%


ME (Kcal / Kg) 1,380 45 75 70 76 66 16 105


Starter 8 14 1.20% 0.54% 0.90% 0.84% 0.90% 0.79% 0.19% 1.26%


ME (Kcal / Kg) 1,400 46 76 69 77 67 16 106


Grower 15 28 1.10% 0.51% 0.84% 0.76% 0.84% 0.74% 0.18% 1.17%


ME (Kcal / Kg) 1,425 47 77 68 78 68 16 107


Finisher 29 42 1.00% 0.47% 0.77% 0.68% 0.77% 0.68% 0.16% 1.07%


ME (Kcal / Kg) 1,450 48 78 68 79 69 16 108


Withdrawal 43 56 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

Baker, D. H., S. R. Fernandez, and D. M. Webel. 1996. Sulfur amino acid requirement and

cysteine replacement value of broiler chicks during the period three to six weeks

posthatching. Poult. Sci. 75:737-742.

Baker, D. H. and Y. Han. 1994. Ideal amino acid profile for chicks during the first weeks

posthatching. Poult. Sci. 73:1441-1447.

Berres, J., S.L. Vieira, W.A. Dozier III, M.E.M. Cortes, R. de Barros, E.T. Nogueira and M.

Kutschenko. 2010. Broiler responses to reduced-protein diets supplemented with valine,

isoleucine, glycine and glutamic acid. Journal of Applied Poultry Science 19:68-79.

Berres, J., S.L. Vieira, A. Favero, D.M. Freitas, J.E.M. Pena and E.T. Nogueira. 2011.

Digestible valine requirements in high protein diets for broilers from twenty-one to forty-two

days of age. Animal Feed Sci, and Technology 165:120-124.

Brito, A., J.H. Stringhini, R.M.J. Filho, S.A.G. Xavier, M.B. Café and N.S.M. Leandro.

2013. Protein and Digestible Threonine Levels in Pre Starter Diets for Broiler Chicks. Int.

Journal of Poultry Science 12 (7):406-410.

Bunchasak, C. 2009. Role of Dietary Methionine in Poultry Production. Japan Poult. Sci. 46:

169-179.




Campos, A., E.T. Nogueira, L.F. Albino and H. Rostagno. 2009a. Effects of digestible

isoleucine :lysine ratios on broiler performance and breast yield. Poultry Science Annual

Meeting. Poster 351. Raleigh, NC.

Campos, A., E.T. Nogueira, L.F. Albino and H. Rostagno. 2009b. Digestible valine : lysine

ratios for broilers during the starter and finisher periods. Poultry Science Annual Meeting.

Poster 352. Raleigh, NC.

Campos, A., H.S. Rostagno, E.T. Nogueira, L.F.T. Albino, J.P.L. Pereira and R.C. Maia.

2012. Updating of the ideal protein for broilers: arginine, isoleucine, valine and tryptophan.

Revista Brasileira de Zootecnia 41 (2):326-332.

Corzo, A. 2012. Determination of the arginine, tryptophan, and glycine ideal-protein ratios

in high-yield broiler chicks. Journal of Applied Poultry Research 21:79-87.

Corzo, A., W.A. Dozier III, and M.T. Kidd. 2008a. Valine nutrient recommendations for

Ross X Ross 308 broilers. Poultry Science. 51 (4) 558-563.

Corzo, A., W.A. Dozier III, M.T. Kidd and D. Hoehler. 2008b. Impact of dietary isoleucine

on heavy-broiler production. International Journal of Poultry Science. 7 (6) 526-529.

Corzo, A., W.A. Dozier III, R.E. Loar II, M.T. Kidd and P.B. Tillman. 2009a. Assessing the

threonine-to-lysine ratio of female broilers from 14 to 28 days of age. Journal of Applied

Poultry Research 18:237-243.

Corzo, A., W.A. Dozier III, R.E. Loar II, M.T. Kidd and P.B. Tillman. 2010. Dietary

limitation of isoleucine and valine in diets based on maize, soybean meal and meat-and-bone

meal for broilers. British Poultry Science. 51 (4) 558-563.




Corzo, A., W.A. Dozier III, L. Mejia, C.D. Zumwalt, M.T. Kidd and P.B. Tillman. 2011.

Nutritional feasibility of L-valine inclusion in commercial broiler diets. Journal of Applied

Poultry Science. 20:284-290.

Corzo, A., M.T. Kidd, W.A. Dozier III and S.L. Vieira. 2007. Marginality and needs of

dietary valine for broilers fed certain all-vegetable diets. Journal of Applied Poultry Research

16:546-554.

Corzo, A., R.E. Loar and M.T. Kidd. 2009b. Limitations of dietary isoleucine and valine in

broiler chick diets. Poultry Science 88:1934-1938.

Corzo, A., E. T. Moran Jr and D. Hoehler. 2004a. Isoleucine need of heavy broiler males.

Arch. Geflugelk 68 (5) 194-198.

Corzo, A., E. T. Moran Jr, and D. Hohler. 2004b. Valine needs of male broilers from 42 to

56 days of age. Poultry Science 83:946-951.

Costa, F.G.P., S.A.N. Morais, E.T. Nogueira, M. Kutschenko, C.C. Goulart, R.C.L. Neto,

C.F.S. Oliveira, V.P. Rodrigues and M.R. Lima. 2010a. Digestible valine:digestible lysine

ratio for broilers in the growing phase. International Poultry Scientific Forum. Abstract P241.

Costa, F. Guilherme Perrazzo, S. Antonio de Normando Moraes, E. Terra Nogueira, M.

Kutschenko, C. Castro Goulart, M. Ramalho de Lima, C. Franklin Santos de Oliveira, R.

Cunha Lima Neto, G. Bruno Vieira Lobato and I. Souza Nobre. 2010b. DVal:dLys ratio for

broiler chickens in the final phase. Proceedings from the XIIIth European Poultry Conference.

Tours, France. August 23-27th. http://www.epc2010.org/




De Beer, M. 2009. Adjusting nutrient density when faced with volatile markets. Arkansas

Nutrition Conference. September. Rogers, Arkansas.

De Beer, M. 2010. Nutrition for maximum profit – Do the math. Aviagen Brief. October. 5

pages.

Dimova, M.D., R.B. Shirley, J.L. Usry, P.B. Tillman, M.E. Freeman and A.J. Davis. 2010.

The digestible lysine requirement of Cobb 500 x Hubbard M99 male broilers from 35 to 49

days of age. Poultry Science Association Annual Meeting. Denver, CO. Nonruminant

Nutrition – AA 1 Abstract and Oral presentation 138. Submitted for publication.

Dozier III, W.A., A. Corzo, M.T. Kidd, P.B. Tillman and S.L. Branton. 2009a. Digestible

lysine requirements of male and female broilers from fourteen to twenty-eight days of age.

Poultry Science 88:1676-1682.

Dozier III, W.A., A. Corzo, M.T. Kidd, P.B. Tillman, J.P. McMurtry and S.L. Branton.

2010a. Digestible lysine requirements of male broilers from 28 to 42 days of age. Poultry Sci.

89: 2173-2182.

Dozier III, W.A., A. Corzo, M.T. Kidd, P.B. Tillman, J.L. Purswell and B.J. Kerr. 2009b.

Dietary lysine requirement of male broilers from 14 to 28 days of age subjected to different

environmental conditions. Journal of Applied Poultry Research 18:690-698.

Dozier III, W.A., A. Corzo, R.E. Loar II, M.T. Kidd and P.B. Tillman. 2011. Determination

of the fourth and fifth limiting amino acids in broilers fed on diets containing maize, soybean

meal and poultry by-product meal from 28 to 42 d of age. British Poultry Science. 52 (2)

238-244.

Dozier, W. A., III and Y. Mercier. 2013a. Digestible total sulfur amino acids to lysine ratio of

broiler chicks from 1 to 15 days of age. Journal of Applied Poultry Research 22:862-871.




Dozier, W. A., III and Y. Mercier. 2013b. Digestible total sulfur amino acid to lysine ratio of

male broilers from forty-two to fifty-six days of age. Poultry Science Association Annual

Meeting, San Diego, CA, Oral Presentation.

Dozier III, W.A., R.L. Payne. 2012. Digestible lysine requirement of female broilers from 14

to 28 days of age. Journal of Applied Poultry Research 21:348-357.

Dozier III, W.A., P.B. Tillman and J. Usry. 2012. Interactive effects of digestible valine and

isoleucine-to-lysine ratios provided to male broilers from 4 to 6 weeks of age. Journal of

Applied Poultry Research 21:838-848.

Duarte, K.F., O.M. Jungueira, R.S. Filardi, J.C. Siqueira, E.A. Garcia and A.C. Laurentiz.

2012. Threonine requirements of 22-42 days-old broilers. Revista Brasileira de Zootecnia

41 (1):72-79.

Eits, R.M., R.P. Kwakkel, M.W.A. Verstegen, and L.A. Den Hartog. 2005a. Dietary

balanced protein in broiler chickens. 1. A flexible and practical tool to predict dose-response

curves. British Poultry Science. 46, 3. 300-309.

Eits, R.M., G.W.G. Giesen, R.P. Kwakkel, M.W.A. Verstegen, and L.A. Den Hartog. 2005b.

Dietary balanced protein in broiler chickens. 1. An Economic Analysis. British Poultry

Science. 46, 3. 310-317.

Everett, D.L., A. Corzo, W.A. Dozier III, P.B. Tillman and M.T. Kidd. 2010. Lysine and

threonine responses in Ross TP16 male broilers. Journal of Applied Poultry Research 19:321-

326.

Garcia, A. and A. B. Batal. 2005. Changes in the digestible lysine and sulfur amino acid needs

of broiler chicks during the first three weeks posthatching. Poult. Sci. 84:1350-1355.




Geraert, PA and Y Mercier. 2010. Amino Acids: Beyond the building blocks. Arkansas

Nutrition Conference Proceedings.

Goodgame, S., C. Coto, F. Mussini, C. Lu, A. Karimi, J. Yuan and P. Waldroup. 2011. The

potential role of valine in commercial poultry diets. International Poultry Scientific Forum.

Abstract P217. Page 30

Goulart, C. de Castro., F.G.P. Costa, J.H.V. de Souza, V.P. Rodrigues, C.L.S. de Oliveira.

2011. Requirements of digestible methionine+cystine for broiler chickens at 1 to 42 days of

age. R. Bras. Zootec., c.40, n.4., 797-803.

Hale, L.L., S.J. Barber, A. Corzo and M.T. Kidd. 2004a. Isoleucine needs of thirty to forty

two day old female chickens: Growth and carcass responses. Poultry Science 83:1986-1991.

Hale, L.L., G.T. Pharr, S.C. Burgess, A. Corzo and M.T. Kidd. 2004b. Isoleucine needs of

thirty to forty two day old female chickens: Immunity. Poultry Science 83:1979-1985.

Helmbrecht, A., F. de Castro Tavernari, H.S. Rostagno, L.F. Teixeira Albino and A. Lemme.

2010. Optimal digestible isoleucine to lysine ratios in starter and finisher broilers.

Proceedings from the XIIIth European Poultry Conference. Tours, France. August 23-27th.

http://www.epc2010.org/

Hsia, L.C., J.H. Hsu and C.T. Liao. 2012. The effect of varying levels of tryptophan on

growth performance and carcass characteristics of growing and finishing broilers. Asian-Aust.

J. Anim. Sci. 18 (2) 230-234.

Jiang, Z, W.A. Dozier and P.B. Tillman. 2014. Digestible Thr to Lys ratio of male broilers

from 21 to 35 days of age. International Poultry Scientific Forum, Atlanta, GA, January.

Metabolism & Nutrition VI Abstract and Oral presentation T138.




Kalinowski, A., E.T. Moran and C. Wyatt. 2003. Methionine and cystine requirements of

slow- and fast-feathering male broilers from zero to three weeks of age. Poultry Science

82:1423-1427.

Kidd, M.T. 2000. Nutritional considerations concerning threonine in broilers. World’s

Poultry Science Journal. 56 (2) 139-151.

Kidd, M.T., D.J. Burnham and B.J. Kerr. 2004. Dietary isoleucine responses in male broiler

chickens. British Poultry Science. 44 (1) 67-75.

Kidd, M.T., W.A. Dozier III, P.B. Tillman, R.E. Loar II, and A. Corzo. 2010. Dietary

addition of L-Valine for commercial broilers. International Poultry Scientific Forum, Atlanta,

GA, January. Nutrition V Abstract and Oral presentation T123.

Kidd, M.T. and L. Hackenhaar. 2005. Dietary threonine for broilers: dietary interactions and

feed additive supplement use. CAB Reviews 1: No 005.

Kidd, M.T., B.J. Kerr, J.P. Allard, S.K. Rao and J.T. Halley. 2000. Limiting amino acid

responses in commercial broilers. Journal of Applied Poultry Research 9:223-233.

Kidd, M.T., S.P. Lerner, J.P. Allard, S.K. Rao and J.T. Halley. 1999. Threonine needs of

finishing broilers: Growth, carcass and economic responses. Journal of Applied Poultry

Research 8 (2) 160-169.

Kidd, M.T. and P.B. Tillman. 2012. Feed Additive Mythbusters: How Should we Feed

Synthetic Amino Acids? February 23. Proceedings of Ajinomoto Animal Nutrition

Technical Seminar. Amino Acid Nutrition in Broiler Diets. Pages 57-64. Bangkok,

Thailand.




Kidd, M.T., P.B. Tillman, P.W.Waldroup and W. Holder. 2013. Feed-grade amino acid use

in the United States: The synergistic inclusion history with linear programming. Journal of

Applied Poultry Research 22:583-590.

Knowles, T. A. and L. L. Southern. 1998. The lysine requirement and ratio of total sulfur

amino acids to lysine for chicks fed adequate or inadequate lysine. Poult. Sci. 77:564-569.

Lemme, Andreas. 2005. Optimum dietary amino acid levels for broiler chicken from

proceedings of the II International Symposium on Nutritional Requirements of Poultry and

Swine. Editors: Horacio Santiago Rostagno and Luiz Fernando Teixeira Albino, held in

Vicosa, MG, Brazil. March 29-31. Pages 117-143.

Lumpkins, B. S., A. B. Batal, and D. H. Baker. 2007. Variations in the digestible sulfur amino

acid requirement of broiler chickens due to sex, growth criteria, rearing environment, and

processing yield characteristics. Poult. Sci. 83:1307-1313.

Mack, S. D. Bercovici, G. de Groote, B. Leclercq, M. Lippens, M. Pack, J. B. Schutte, and S.

Van

Cauwenberghe. 1999. Ideal amino acid profile and dietary lysine specification for broiler

chickens of 20 to 40 days of age. Br. Poult. Sci. 40:257-265.

Maia, R.C., S.C. Saiguero, T.A. Carvalho, E.T. Nogueira, L.F.T. Albino and H.S. Rostagno.

2012. Effect of normal and high dietary levels of isoleucine, Leucine and valine on

performance of broiler chickens from 14-23 days of age. World’s Poultry Science Journal,

Supplement 1, Expanded Abstract – Poster Presentation. Worlds Poultry Congress – Bahia,

Brazil August 5-9.

Mehri, A., A. Davarpanah and H.R. Mirzaei. 2012. Estimation of ideal ratios of methionine

and threonine to lysine in starting broiler chicks using response surface methodology. Poultry

Science 91:771-777.




Meloche, K.J., P.B. Tillman and W.A. Dozier III. 2013. Growth performance of male

broilers fed diets varying in digestible threonine from 1 to 14 days of age. International

Poultry Scientific Forum, Atlanta, GA, January. Metabolism & Nutrition I Abstract and Oral

presentation M27.

Mejia, L., D. Morgan, P. Tillman, W. Zhai. 2013. Increased amino acid density, reduced

metabolizable energy and inclusion of L-Threonine maximizes performance and profitability

in Ross X Ross 708 male broilers. International Poultry Scientific Forum, Atlanta, GA,

January. Metabolism & Nutrition II Abstract and Oral presentation M62.

Mejia, L., P.B. Tillman, C.D. Zumwalt and A. Corzo. 2012. Assessment of the threonine-to-

lysine ratio of male broilers from 35 to 49 days-of-age. Journal of Applied Poultry Science.

21:235-242.

Mejia, L., C.D. Zumwalt, E.J. Kim, P.B. Tillman and A. Corzo. 2011.. Digestible isoleucine-

to-lysine ratio effects in diets for broilers from 4- to 6-weeks posthatch. Journal of Applied

Poultry Science. 20:485-490.

Mejia, L., C.D. Zumwalt, P.B. Tillman, R.B. Shirley and A. Corzo. 2012. Assessment of the

digestible arginine-to-digestible lysine ratio of male broilers from 28 to 42 days-of-age a

constant, elevated environmental temperature regimen. Journal of Applied Poultry Science.

21:305-310.

Meloche, K., P. Tillman, W. Dozier III. 2013. Growth performance of male broilers fed diets

varying in digestible threonine from 1 to 14 days of age. . International Poultry Scientific

Forum, Atlanta, GA, January. Metabolism & Nutrition I Abstract and Oral presentation M27.

McGill, E., A. Kamyab and J.D. Firman. 2012. Low Crude Protein Corn and Soybean Meal

Diets with Amino Acid Supplementation for Broilers in the Starter Period 1. Effects of

Feeding 15% Crude Protein. Int. Journal of Poultry Science 11 (3):161-165.




Morris, T.R. 1983. The Interpretation of Response Data from Animal Feeding Trials in

Recent Advances in Animal Nutrition. Chapter 1. Pages 1-11.

Nasr, J., F. Kheri. 2012. Effects of Lysine Levels of Diets Formulated Based on Total or

Digestible Amino Acids on Broiler Carcass Composition. Brazilian J. of Poult. Sci. Oct-Dec.

v.14 n.4 233-304.

Neto, R.M., M.L. Ceccantini and J.I.M. Fernandes. 2013. Effects of methionine source,

arginine:lysine ratio and sodium chloride level in the diets of grower broilers reared under

high-temperature conditions. Brazilian J. of Poult. Sci. Apr-Jun. v.15 n.2 151-160.

NRC. 1994. Nutrient Requirements of Poultry. 9th ed. Natl. Acad. Press, Washington, DC.

Oliveira, W.P, R.F.M Oliveira, J.P. Donzele, L.F.T. Albino, P.H.R.F. Campos, E.M. Balbino,

A.P. Maia and S.M. Pastora. 2013. Lysine levels in diets for broilers from 8 to 21 days of

age. Revista Brasileira de Zootecnia 42 (12):869-878.

Pack, M., D. Hoehler and A, Lemme. 2003. Economic assessment of amino acid responses

in growing poultry, in Amino Acids in Animal Nutrition. 2nd edition. J.P.F. D’Mello Editor.

CABI Publishing, Wallingford, UK. Pages 459-483.

Pastor, A., C. Wecke and F. Liebert. 2013. Assessing the age-dependent optimal dietary

branched-chain amino acid ratio in growing chickens by application of a nonlinear modeling

procedure. Poultry Science 92:3184-3195.

Perryman, K., P. Tillman, W. Dozier III. 2013. Increased dietary amino acid density from 1

to 42 d of age optimizes profitability in Ross X Ross 708 male broilers. International Poultry

Scientific Forum, Atlanta, GA, January. Metabolism & Nutrition I Abstract and Oral

presentation M29.




Rodehutscord, M., A.A. Fatufe. 2005. Protein and valine gain of broilers in response to

supplemental L-Valine. Proceedings of the 15th European Symposium on Poultry Nutrition,

World's Poultry Science Association. Balatonfüred, Hungary. September 25-29. 545-547.

Rostagno, H.S., Albino, L.F.T., Donzele, J. L., Gomes, P.C., de Olveira, R.F., Lopes, D.C.,

Firiera, A.S., and Barreto, S.L. de T., 2005. Brazilian Tables for Poultry and Swine.

Composition of Feedstuffs and Nutritional Requirements. 2nd ed. H. S. Rostagno, ed.

Universidade Federal de Vicosa, Dept. Zootecnia, Vicosa, MG, Brazil.

Rostagno, H.S., L.F.T. Albino, J.L. Donzele, P.C. Gomes, R. Flavia de Olveira, Lopes, A.S.

Ferreira, S.L de Toledo Barreto and R.F. Euclides. 2011. Brazilian Tables for Poultry and

Swine. Composition of Feedstuffs and Nutritional Requirements. 3rd ed. H. S. Rostagno, ed.

Universidade Federal de Vicosa, Dept. Zootecnia, Vicosa, MG, Brazil.

Rostagno, H., L Pae’z and L. Albino. 2007. Nutrient requirements for broilers for optimum

growth and lean mass. World’s Poultry Science Association. XVI European Symposium

Poultry Nutrition. Strasbourg, France.

Rubin, L.L., C.W. Canal, A.L.M. Ribeiro, A. Kessler, I. Silva, L. Trevizan, T. Viola, M.

Raber, T.A. Gonalves and R. Kras. 2007. Effects of methionine and arginine dietary levels

on the immunity of broiler chickens submitted to immunological stimuli. Brazilian J. of

Poult. Sci. Oct-Dec. v.9 n.4 241-247.

Rubin, L.L., A.M.L. Ribeiro, C.W. Canal, I.C. Silva, L. Trevizan, L.K. Vogt, R.A. Pereira

and L. Lacerda. 2007. Influence of sulphur amino acid levels in diets of broiler chickens

submitted to immune stress. Brazilian J. of Poult. Sci. Oct-Dec. v.9 n.1 53-59.

Shirley, R.B., J.L. Usry and P.B. Tillman. 2009. The digestible lysine requirement of fast-

feathering, straight-run, 35 to 45 day-old Cobb x Cobb 500 broilers. International Poultry

Scientific Forum, Atlanta, GA, January. Nutrition III Abstract and Oral presentation M67.




Siqueira, J.C., N.K. Sakomura, L.R.B. Dourado, J.M.B. Ezequiel, N.A.A. Barbosa and J.B.K.

Fernandes. 2013. Diet formulation techniques and lysine requirements of 1-22 day-old

broilers. Brazilian J. of Poult. Sci. Apr-Jun. v.15 n.2 123-134.

Sriperm. 2011a. Optimal broiler production via nutrition. Agricultural Economics Masters

thesis. University of Georgia. Athens, GA. 63 pages.

Sriperm, N. 2011b. Protein and amino acid content of feed ingredients and the impact of

dietary balanced protein on maximizing economic returns from broiler technical responses.

Poultry Science Doctoral dissertation. University of Georgia. Athens, GA. 174 pages.

Sriperm, N., P.B. Tillman, G.M. Pesti and M.E. Wetzstein. 2008. An economic analysis of

L-Threonine in a broiler grower diet, using a least-cost model, based upon digestible amino

acids and ideal digestible amino acid ratios. Poultry Science Association Annual Meeting.

Niagara Falls, Canada.

Star, L., M. Rovers, E. Corrent and J.D. van der Klis. 2012. Threonine requirement of broiler

chickens during subclinical intestinal Clostridium infection. Poultry Science 91 : 643-652

Tavernari, F.C., G.R. Lelis, P.R.O Carneiro, R.A. Vieira, R.C. Polveiro, J.A.P. Luengas, H.S.

Rostagno and L.F.T. Albino.. 2012. Effect of different digestible isoleucine/lysine ratios for

broiler chickens. Revista Brasileira de Zootecnia 41 (7):1699-1705.

Tavernari, F.C., G.R. Lelis, R.A. Vieira, H.S. Rostagno, L.F.T. Albino and A.R. Oliveira

Neto. 2013. Valine needs in starting and growing Cobb (500) broilers. Poultry Science

92:151-157.

Thornton, S.A., A. Corzo, G.T. Pharr, W.A. Dozier III, D.M. Miles and M.T. Kidd. 2006.

Valine requirements for immune and growth responses in broilers from 3 to 6 weeks of age.

British Poultry Science 47 (2) April. 190-199.




Tillman, P.B. Reducing broiler feed cost with L-Threonine. 19th Annual Philsan

Convention, 2006. “Cutting-Edge” Nutrition: A Challenge to Animal Nutritionists. October

6th. Cebu City, Philippines.

Tillman, P.B. 2007. Practical application of L-Threonine in broiler nutrition Proceedings of

the Arkansas Nutrition Conference. September 12th Rogers, Arkansas.

Tillman, P.B. Amino acid nutrition and incorporating L-Threonine in broiler formulas. 2008

Proceedings of the Mid-Atlantic Nutrition Conference. March 27th. Timonium, MD.

Tillman, P.B. 2010a. An update on amino acid requirements for broilers and layers.

(Actualización de la nutrición con aminoacididos para pollos y gallina de postura). XXI

Congreso Centroamericano y del Caribe de Avicultura. San Jose, Costa Rica. June 16-18.

Tillman, P.B. 2010b. Improving environmental sustainability of poultry production with

amino acids. Proceeding of the Multi-State Poultry Feeding and Nutrition Conference.

Session C : Environmental Nutrition. Indianapolis, IN. May 25th-27th.

Tillman, P.B. 2011a. Special Considerations for Amino Acids in Broiler Nutrition. III

International Symposium on Nutritional Requirements of Poultry and Swine. March 29-31.

Pages 21-44. Vicosa, Brazil.

Tillman, P.B. 2012. Current Amino Acid Considerations for Broiler Diets : Requirements,

Ratios, Economics. February 23. Proceedings of Ajinomoto Animal Nutrition Technical

Seminar. Amino Acid Nutrition in Broiler Diets. Pages 24-56. Bangkok, Thailand.

Tillman, P.B. and W.A. Dozier III., 2013. Current Amino Acid Considerations for Broilers :

Requirements, Ratios and Economics. In Pre-Symposium from Proceedings of Arkansas

Nutrition Conference by Adisseo, Rogers, AR. September 3-5.




Tillman, P.B., L. Mejia, A. Corzo and R.L. Shirley. 2011. Assessment of the digestible

Arginine : lysine ratio of 28 to 42 day of age male broilers under an increasing temperature

regimen. International Poultry Scientific Forum, Atlanta, GA, January. Nutrition Abstract

and Oral presentation 99 : Page 29.

Tillman, P., K. Perryman, W. Dozier III. 2013. Increased dietary amino acid density from 1

to 35 d of age optimizes profitability in Hubbard M88 X Cobb 500 male broilers.

International Poultry Scientific Forum, Atlanta, GA, January. Metabolism & Nutrition II

Abstract and Oral presentation M61.

Tillman, P.B. and N. Sriperm. 2011b. Estimating Amino Acid Requirements of Broilers

using Static : Production and Dynamic : Market Based Analysis. September 6. Pre-

Symposium of Arkansas Nutrition Conference by Huvepharma, Rogers, AR.

Wecke, C and F. Liebert. 2013. Improving the Reliability of Optimal In-Feed Amino Acid

Ratios Based on Individual Amino Acid Efficiency Data from N Balance Studies in Growing

Chickens. Animals 3, 558-573.

Zhai, W., E.B. Peebles, C.D. Zumwalt, L. Mejia and A. Corzo. 2013. Effects of dietary

amino acid density regimens on growth performance and meat yield of Cobb x Cobb 700

broilers. Journal of Applied Poultry Research 22:447-460.

Ziggers, D. 2011. Optimising nutrient density in a volatile market. All About Feed. Vol. 2.,

No. 3. 18-20.

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