J. Appl. Poult. Res.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J APPL POULT RES 2007. 16:331-343
© 2007 Poultry Science Association
This Article
Right arrow Summary Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Dozier, W. A.
Right arrow Articles by Branton, S. L.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Dozier, W. A., III
Right arrow Articles by Branton, S. L.

Research Reports

Dietary Amino Acid Responses of Mixed-Sex Broiler Chickens From Two to Four Kilograms1

W. A. Dozier, III*,2, M. T. Kidd{dagger}, A. Corzo{dagger}, J. Anderson{ddagger} and S. L. Branton*

* USDA, Agricultural Research Service, Poultry Research Unit, {dagger} Department of Poultry Science, and {ddagger} Department of Agricultural Economics, Mississippi State University, Mississippi State, MS 39762

Correspondence: 2 Corresponding author: bdozier{at}msa-msstate.ars.usda.gov


   SUMMARY
TOP
 SUMMARY
DESCRIPTION OF PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
Two experiments were conducted to assess dietary amino acid density responses on mixed-sex broiler live performance, meat yields, and economics from 36 to 60 d. In experiment 1, broilers were fed a common feeding program to 35 d. Dietary treatments were high (H), moderate (M), and low (L) amino acid density from 36 to 47 d of age and H or L amino acid density from 48 to 60 d of age. Dietary treatments were high-high (HH), high-low (HL), moderate-low (ML), and low-low (LL) during a 60-d production period. In experiment 2, common diets were provided from 1 to 47 d of age. Dietary treatments were H, M, L, and suboptimum (S) amino acid density and fed from 48 to 60 d of age. In experiment 1, increasing dietary amino acid density to HH improved cumulative feed conversion (1 to 60 d) by 4 points over the ML- and LL-fed birds. Broilers provided the HH regimen had 0.6% more total breast meat yield than the LL-fed birds. In experiment 2, broilers fed the H feeding regimen lowered cumulative (1 to 60 d) feed conversion by 3, 5, and 6 points and reduced abdominal fat percentage by 0.28, 0.23, and 0.23%, respectively, compared with the M-, L-, and S-fed birds. Decreasing dietary amino acid density from H to S reduced total breast meat weight and yield by 47 g and 0.82%, respectively. In general, feeding HL (experiment 1) and H (experiment 2) diets increased gross feed margins over the other dietary treatments with diverse diet cost and meat price scenarios.

Key Words: amino acid • broiler • lysine • methionine • nutrient density


   DESCRIPTION OF PROBLEM
TOP
 SUMMARY
 DESCRIPTION OF PROBLEM
MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
From 2000 to 2005, broiler chickens marketed to 3.4 kg or greater have increased from 0 to 13% of the total number of broilers marketed in the United States [1]. Demand for breast fillets and value-added products has resulted in an increased number of broilers processed to heavy weights. Dietary amino acid responses of broilers grown to 2.5 kg are well established [2, 3, 4, 5]. Dietary amino acid recommendations are limited on broilers grown to 3.4 kg or greater. Primary breeding guides provide nutrient recommendations to a maximum BW of 3.0 kg [6, 7]. Most feed cost for growing heavy broilers occurs from 5 to 9 wk of age, because approximately 4.5 kg of feed is consumed per bird during this period. Therefore, determining dietary amino acid needs is warranted during 5 to 9 wk of age because of its high economic effect.

Feeding high amino acid density diets improves feed conversion and increases breast meat yield of broiler chickens [2, 3, 4, 5, 8, 9, 10, 11]. Determining the duration that high (H) amino acid-dense diets should be fed to heavy broilers is not well defined. Dietary amino acid research has evaluated responses throughout the life cycle of the broiler [9, 10, 11], and carryover effects may have occurred from the starter and grower periods to the end of the grow-out.

Dozier et al. [8] evaluated dietary amino acid responses from 36 to 59 d of age. Cumulative feed conversion and total breast meat yield were adversely affected as dietary amino acid density was decreased from high-high (HH) to low-low (LL) diets during 36 to 47 and 48 to 59 d of age. Dietary digestible Lys was 0.93 and 0.89% for the HH-fed broilers and 0.75 and 0.72% with the LL regimen, which may have been too low. Also in this study, broilers fed digestible dietary Lys of 0.84 and 0.72% from 36 to 47 and 48 to 59 d, respectively, had similar total breast meat yield to the HH-fed birds. This indicates that dietary amino acid density can be reduced from 48 to 59 d without affecting total breast meat yield if adequate amino acid concentrations are fed from 1 to 47 d of age.

Research is needed to further examine dietary amino acid needs during the third and fourth phase feeds of mixed-sex broilers grown to 4.0 kg. Two experiments were conducted to evaluate dietary amino acid responses on growth, meat yield, and economics from 36 to 60 d. Experiment 1 assessed dietary amino acid needs during 36 to 47 d on subsequent 60 d performance, whereas experiment 2 examined responses to dietary amino acid density from 48 to 60 d.


   MATERIALS AND METHODS
TOP
 SUMMARY
 DESCRIPTION OF PROBLEM
 MATERIALS AND METHODS
RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
Bird Husbandry
Ross x Ross 708 [12] one-day-old broiler chicks (experiment 1 = 1,664 chicks; experiment 2 = 1,600 chicks) were purchased from a commercial hatchery, feather-sexed, and randomly distributed into 32 floor pens (experiment 1 = 26 males and 26 females per pen, 0.08 m2/bird; experiment 2 = 25 males and 25 females per pen, 0.08 m2/bird). Chicks were vaccinated at the hatchery for Marek’s disease, Newcastle disease, and infectious bronchitis and in the research facility for Gumboro at 12 d of age. Each pen was equipped with a pan feeder, a drinker line having 9 nipples, and fresh pine shavings. A feeder tray was provided in each pen from 1 to 7 d to insure chicks had access to feed. Temperature was set at 34°C and reduced as birds advanced in age, with a final set point being 14°C at 55 d of age [13]. The lighting schedule used simulated commercial practice [14].

Treatments
Corn, soybean meal, and poultry by-product meal used during the experimental periods (experiment 1 = 36 to 60 d; experiment 2 = 48 to 60 d) were analyzed for amino acid [15] and CP [16] composition before formulation. Digestible amino acid values were determined from digestible coefficients previously reported [17] and analyzed total amino acid content of the ingredients. Digestible and total amino acid concentrations were used in the ingredient matrix with least cost formulation. After experimentation, diets were analyzed for amino acid and CP concentrations [15, 16].

In experiment 1, broilers were provided common diets from 1 to 35 d of age (Table 1Go). At 36 to 60 d of age, broilers were provided 4 dietary regimens that were formulated to H, moderate (M), and low (L) amino acid density (Table 2Go). Dietary amino acid density was characterized as H, M, and L from 36 to 47 d of age and H and L from 48 to 60 d of age. Diets being described as H, M, and L were based upon commercial formulations used by broiler integrators. Dietary treatments were HH, high-low (HL), moderate-low (ML), and LL for the 60-d production period. For example, ML would represent M for the withdrawal (WD) 1 period (36 to 47 d) and L for the WD2 period (48 to 60 d). Digestible TSAA, Lys, and CP percentages were increased in the LL diets compared with specifications used in previous research [8]. Amino acid concentrations in the LL regimen were increased to minimize a difference with breast meat yield compared with the HH regimen.


View this table:
[in this window]
[in a new window]

  		Table 1. Ingredient and calculated nutrient composition of diets provided to male and female broilers before the experimental period1 (experiment 1 and 2)
 

View this table:
[in this window]
[in a new window]

  		Table 2. Ingredient and calculated nutrient composition of diets provided to male and female broilers from 36 to 60 d of age (experiment 1)
 
In experiment 2, broilers were fed common diets from 1 to 47 d of age (Table 1Go). Digestible Lys, TSAA, and CP concentrations provided from 36 to 47 d of age were an average of the H and M amino acid density used in experiment 1. From 48 to 60 d of age, experimental diets were denoted as H, M, L, and suboptimum (S; Table 3Go).


View this table:
[in this window]
[in a new window]

  		Table 3. Ingredient and calculated nutrient composition of diets provided to male and female broilers from 48 to 60 d of age (experiment 2)
 
Measurements
Pen BW and feed were weighed at 1, 17, 35, 48, and 60 d of age. Feed consumption was corrected for mortality based on number of bird days. Weighing birds and feed at 1, 17, 35, 48, and 60 d of age enabled the calculation of cumulative effects (total feed consumed and total BW gain) on growth performance and economics. Mortality was recorded daily. At 60 d of age, 12 birds per pen were selected for processing. Within each pen, birds were placed in 6 coops (8 or 9 birds per coop) for weighing, and 2 birds (1 male and 1 female) per coop were randomly selected and tagged for processing. Feed was removed 12 h before processing. At d 61, birds selected for processing were weighed, placed in coops, and transported to the Mississippi State University Processing Plant. Birds were electrically stunned, bled, scalded, defeathered, and manually eviscerated. Carcasses (without abdominal fat) and abdominal fat were weighed. Carcasses were cut into front and back halves. Front halves were chilled in ice for 18 h and then deboned to obtain pectoralis major and minor muscle weights. Carcass, abdominal fat, and breast meat yields were determined from d-61 BW of the birds selected for processing.

Economics
Sensitivity analysis was conducted to determine gross feeding margin based on carcass and breast meat weight. Sensitivity analysis can be defined as the process of evaluating the effect on the output from a model of changes in key variables (over a reasonable range). Examples of sensitivity analysis in the context of economic decision-making are numerous in the agricultural economics literature [18, 19, 20]. The sensitivity analysis allowed determination of gross feeding margin for a given scenario as influenced by dietary treatments. Thirty-five scenarios were developed to estimate gross feeding margin per bird based on varying diet cost and meat prices. Diet costs were considered the base price (100%) and decreased to 80% of the base cost and increased to 120% of the base cost to reflect market price fluctuations occurring during a 12-mo period. Base diet costs were estimated on southeastern United States ingredient prices as of March 2006. Base meat prices were $1.32/kg, $3.32/kg, and $3.97/kg to represent carcass, pectoralis major, and pectoralis minor muscle prices, respectively. Meat prices varied from 70 to 130% of the base prices for carcass, pectoralis major, and pectoralis minor muscle prices. Gross feeding margin per bird was calculated as output value (meat price x meat weight) minus input cost (feed cost = diet cost x feed consumption) [21].

Statistics
Data were statistically evaluated in a 1-way treatment structure using a least significant difference comparison of the GLM procedure of SAS [22] and planned orthogonal contrasts for mean separation. The design structure was a randomized complete block with pen location as the blocking factor. Each treatment was represented by 8 replicate pens. Pen was considered the experimental unit. Body weight at 35 and 48 d, respectively, in experiment 1 and 2 was used as a covariant in the analysis of growth performance data from 36 to 47- and 36 to 60-d periods for experiment 1 and a 48 to 60-d period in experiment 2. The use of a covariant may account for some differences due to sex within pens that may have occurred to mortality. Statistical significance was considered at P ≤ 0.05.


   RESULTS AND DISCUSSION
TOP
 SUMMARY
 DESCRIPTION OF PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
Experiment 1
Analyzed dietary amino acid and CP concentrations for experimental diets in experiment 1 were in close agreement with calculated values (Table 2Go). Body weight at 35 d was used as a covariant to account for sex if the ratio of male to female changed due to mortality even though each pen contained 50% males and 50% females at placement. Decreasing dietary amino acid density from H and M to L increased (P ≤ 0.01) 36 to 47-d feed conversion by 14 and 11 points, respectively (Table 4Go). Dietary treatments did not influence BW gain and feed consumption from 36 to 47 d of age. No treatment differences were observed in growth performance from 36 to 60 d. Cumulative (1 to 60 d) feed conversion increased when dietary amino acid density was decreased from HH and HL to LL (Table 4Go). However, only a 4-point difference in cumulative feed conversion occurred between the HH and LL regimens. As dietary amino acid density was decreased, cumulative BW, BW gain, feed consumption, and mortality were unaffected.


View this table:
[in this window]
[in a new window]

  		Table 4. Live performance responses of male and female broiler diets provided varying in dietary amino acid density from 36 to 60 d of age (experiment 1)1
 
Providing the LL regimen to broilers limited (P ≤ 0.05) the weight and percentage of total breast meat (Table 5Go). Conversely, carcass weight and its percentage yield were not influenced by the dietary treatments. Broilers fed the HH regimen had lower abdominal fat percentage than ML- and LL-fed broilers, but abdominal fat weight was similar among the treatments. The amount of Lys, TSAA, and Thr consumed for the HH (Lys, 41 g; TSAA, 32 g; Thr, 28 g), HL (Lys, 39 g; TSAA, 30 g; Thr, 26 g), ML (Lys, 37 g; TSAA, 29 g; Thr, 25 g), and LL (Lys, 36 g; TSAA, 28 g; Thr, 25 g) diets. Lysine, TSAA, and Thr consumption of 36, 28, and 25 g, respectively, of the LL-fed birds adversely affected cumulative feed conversion and breast meat yield.


View this table:
[in this window]
[in a new window]

  		Table 5. Carcass measurements of male and female broilers provided diets varying in dietary amino acid density from 36 to 60 d of age (experiment 1)1
 
Feeding broilers the HL regimen led to economically higher gross feeding margins compared with the other treatments regardless of changes in diet cost and breast meat prices (Table 6Go). For example, HL-fed birds had higher differences in gross feeding margins of $0.023, $0.041, and $0.084 per bird compared with HH, ML, and LL regimens, respectively, at 100% of base diet cost and 70% of base breast meat price. As meat prices were increased to 130% of the base and 100% of base diet cost, HL had greater differences in gross feeding margins of $0.028, $0.083, and $0.162 per bird than HH, ML, and LL regimens, respectively. Increasing diet cost to 120% of the base with 100% of base breast meat price resulted in advantages of gross feeding margins of $0.029, $0.060, and $0.122 per bird when the HL regimen was fed compared with HH, ML, and LL, respectively.


View this table:
[in this window]
[in a new window]

  		Table 6. Gross feeding margin ($/bird) based upon total feed cost and meat yield of male and female broilers provided diets varying in amino acid density from 36 to 60 d of age (experiment 1)
 
Experiment 2
Actual amino acid and CP values of experimental diets were lower than the expected values in experiment 2, but differences were similar across all treatments (Table 3Go). Body weight at 48 d was used as a covariant to account for sex if the ratio of male to female changed due to mortality even though each pen contained 50% males and 50% females at placement. Broilers fed the H and M diets had 29 and 19 points, respectively, lower (P ≤ 0.02) 48 to 60-d feed conversion than broilers fed the L and S diets (Table 7Go). Broilers fed the S diet consumed (P ≤ 0.001) more feed from 48 to 60 d compared with birds provided the other dietary treatments. Providing broilers with the H diet from 48 to 60 d increased (P ≤ 0.05) BW gain compared with the L-fed birds. Decreasing amino acid density from H to M, L, and S increased (P ≤ 0.05) cumulative (1 to 60 d) feed conversion by 3, 4, and 5 points, respectively. As dietary amino acid density decreased from H to S, feed consumption was increased (P ≤ 0.05) by 0.129 kg/bird. Body weight, BW gain, and mortality were not influenced by the dietary treatments. Providing broilers with the S regimen decreased (P ≤ 0.03) carcass and total breast meat yields compared with H-fed birds (Table 8Go). Decreasing amino acid density from H to M, but not L, decreased (P ≤ 0.03) breast meat yield. Carcass and breast meat yields were not affected as dietary amino acid density was decreased from M and L to S regimens. The H-fed birds had lower (P ≤ 0.01) abdominal fat percentage than the other dietary treatments. Lysine, TSAA, and Thr consumption from 48 to 60 d for the H (Lys, 21 g; TSAA, 16 g; Thr, 14 g), M (Lys, 20 g; TSAA, 15 g; Thr, 13 g), L (Lys, 18 g; TSAA, 14 g; Thr, 12 g), and S (Lys, 17 g; TSAA, 13 g; Thr, 12 g) regimens. Broilers consumed 21, 16, and 14 g of Lys, TSAA, and Thr, respectively, with the H diet to optimized cumulative feed conversion and breast meat yield.


View this table:
[in this window]
[in a new window]

  		Table 7. Live performance responses of male and female broiler diets provided varying in dietary amino acid density from 48 to 60 d of age (experiment 2)1
 

View this table:
[in this window]
[in a new window]

  		Table 8. Carcass measurements of male and female broilers provided diets varying in dietary amino acid density from 48 to 60 d of age (experiment 2)1
 
Broilers fed the H regimen had the highest gross feeding margin with varying diet costs and breast meat prices (Table 9Go). With 100% of base diet cost and 70% of base breast meat price, providing the H regimen had gross feeding margins of $0.061, $0.042, and $0.100 per bird more than M, L, and S regimens, respectively. Given a base diet cost of 100 and 130% of base breast meat price, broilers fed the H regimen had higher gross feeding margins of $0.119, $0.090, and $0.191 per bird compared with M, L, and S, respectively. When holding breast meat at 100% of the base price and increasing diet cost to 120% of the base, the H regimen had greater gross feeding margins of $0.088, $0.062, and $0.143 per bird as birds given M, L, and S regimens, respectively.


View this table:
[in this window]
[in a new window]

  		Table 9. Gross feeding margin ($/bird) based upon total feed cost and meat yield of male and female broilers provided diets varying in amino acid density from 48 to 60 d of age (experiment 2)
 
Dozier et al. [8] reported poorer feed conversion as dietary amino acid density was decreased from 36 to 59 d of age. It was found that decreasing amino acid density from HH (digestible Lys, 0.93% from 36 to 47 d; digestible Lys, 0.89% from 48 to 59 d) to LL (digestible Lys, 0.75% from 36 to 47 d; digestible Lys, 0.72% from 48 to 59 d) reduced total breast meat by 22 g per bird. In experiment 1 of the current research, as dietary amino acid density was decreased from HH (digestible Lys, 0.92% from 36 to 47 d; digestible Lys, 0.88% from 48 to 59 d) to LL (digestible Lys, 0.78% from 36 to 47 d; digestible Lys, 0.72% from 48 to 59 d), total breast meat was decreased by 44 g per bird. Increasing digestible Lys concentration from 0.75 [8] to 0.78% in experiment 1 during 36 to 47 d did not alleviate the reduction in breast meat, indicating broilers may have a higher need for amino acids than the LL regimen provided. Lysine consumption for the LL treatment was 38 g per bird with previous research [8], whereas Lys consumption was 36 g per bird for the LL in experiment 1 of the current research. Even though dietary Lys was increased with LL treatment in experiment 1 compared with a previous report [8], the reduction in Lys intake was likely due to unseasonably high ambient temperatures [13] that occurred during experiment 1 of the current research.

In experiment 2 of the current research, breast meat yield was not significantly affected as amino acid density was reduced from H (digestible Lys, 0.87% from 48 to 60 d) to L (digestible Lys, 0.75% from 48 to 60 d), but breast yield was lower when the M diet was fed (digestible Lys, 0.81% from 48 to 60 d). Breast meat yield was not different when broilers were provided the M diet compared with L-fed birds. Lysine consumption from 48 to 60 d was 20 g for birds provided the M diet and 18 g for the L-fed broilers. Least significance difference critical value was 0.48 for breast meat yield, and the breast meat yield difference from H to M was 0.53 and 0.46% from H to L. Difference of breast meat yield between H- and L-fed birds was 0.46%, and the critical value was 0.48. In addition, breast meat weight was reduced as dietary amino acid density decreased (P = 0.052) from H to M, but it was similar with H compared with L. The least significance difference critical value for breast meat weight was 0.033, and the breast meat weight difference between H and L treatments was 0.027 kg.

Decreasing dietary amino acid density from HH to HL did not affect breast meat weight or yield in experiment 1. Conversely, in experiment 2, H-fed broilers had more breast meat weight (P = 0.052) and yield than birds provided M diets. Environmental conditions were more favorable for broiler growth in experiment 2 than experiment 1, leading to heavier BW in experiment 2 (4.0 kg) compared with experiment 1 (3.5 kg). A higher growth rate of broilers in experiment 2 may have resulted in a more pronounced response to H diets with breast meat yield than experiment 1.

Growth rate response to dietary amino acid density has been significantly affected by dietary amino acid density with broilers grown to 2.5 kg [5], whereas BW was not influenced by dietary amino acid density from 2.0 to 4.0 kg in both previous [8, 9] and current research. Dietary amino acid density affects feed conversion more acutely than growth in broilers from 2.0 to 4.0 kg. In addition, abdominal fat percentage is decreased by increasing dietary amino acid density during 5 to 9 wk of age with both previous [8] and current research. As dietary amino acid density was decreased from H to L during 36 to 47 d of age, feed consumption was significantly increased [8]. Dietary amino acid density appears to affect feed consumption, which in turn influences caloric consumption leading to differences in abdominal fat percentage. Breast meat development is also influenced by dietary amino acid density during 5 to 9 wk of age. Dietary Lys is known to be central in breast meat accretion [23], with its content being higher in breast meat compared with other muscles.


   CONCLUSIONS AND APPLICATIONS
TOP
 SUMMARY
 DESCRIPTION OF PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
REFERENCES AND NOTES
 

  1. Broilers provided the H amino acid density diet optimized cumulative feed conversion, and decreasing dietary amino acid density to the L regimen tended to reduce total breast meat weight and yield.
  2. Broilers fed less dense amino acid diets had the ability to increase feed consumption, which in turn increased abdominal fat yield.
  3. In general, with the 35 economic scenarios, feeding H amino acid density diets to broilers increased gross feeding margin.


   FOOTNOTES
 
1 Mention of trade names or commercial products in this publication is solely to provide specific information and does not imply recommendation or endorsement by the USDA. Back


   REFERENCES AND NOTES
TOP
 SUMMARY
 DESCRIPTION OF PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 

  1. Allard, J. 2005. Status of broiler nutrition in the United States. Proc. Arkansas Nutr. Conf., Springdale. Arkansas, Missouri, and Oklahoma Poult. Fed., Rogers, AR.
  2. Dozier, W. A., III, and E. T. Moran Jr. 2001. Response of early- and late-developing broilers to nutritionally adequate and restrictive feeding regimens during the summer. J. Appl. Poult. Res. 10:92–98.[Abstract/Free Full Text]
  3. Kidd, M. T., B. J. Kerr, K. M. Halpin, G. W. McWard, and C. L. Quarles. 1998. Lysine interactions in broilers in starter and grower-finisher diets. J. Appl. Poult. Res. 7:351–358.[Abstract/Free Full Text]
  4. Hickling, D., W. Guenter, and M. E. Jackson. 1990. The effects of dietary methionine and lysine on broiler chicken performance and breast meat yield. Can. J. Anim. Sci. 70:673–678.
  5. Kidd, M. T., C. D. McDaniel, S. L. Branton, E. R. Miller, B. B. Boren, and B. I. Fancher. 2004. Increasing amino acid density improves live performance and carcass yields of commercial broilers. J. Appl. Poult. Res. 13:593–604.[Abstract/Free Full Text]
  6. Aviagen North America. 2003. Ross x Ross 708 North American Broiler Performance Objectives. Aviagen North America, Huntsville, AL.
  7. Aviagen North America. 2003. Ross x Ross 508 North American Broiler Performance Objectives. Aviagen North America, Huntsville, AL.
  8. Dozier, W. A., III, M. T. Kidd, A. Corzo, J. Anderson, and S. L. Branton. 2006. Growth performance, meat yield, and economic responses of broilers provided diets varying in amino acid density from thirty-six to fifty-nine days of age. J. Appl. Poult. Res. 15:367–382.[Abstract/Free Full Text]
  9. Kidd, M. T., A. Corzo, D. Hoehler, E. R. Miller, and W. A. Dozier III. 2005. Broiler responsiveness (Ross x 708) to diets varying in amino acid density. Poult. Sci. 84:1389–1396.[Abstract/Free Full Text]
  10. Corzo, A., M. T. Kidd, D. J. Burhnham, E. R. Miller, S. L. Branton, and R. Gonzalez-Esquerra. 2005. Dietary amino acid density effects on growth and carcass of broilers differing in strain cross and sex. J. Appl. Poult. Res. 14:1–9.[Abstract/Free Full Text]
  11. Dozier, W. A., III, R. W. Gordon, J. Anderson, M. T. Kidd, A. Corzo, and S. L. Branton. 2006. Growth, meat yield, and economic responses of broilers provided three- and four-phase schedules formulated to moderate and high nutrient density during a fifty-six day production period. J. Appl. Poult. Res. 15:312–325.[Abstract/Free Full Text]
  12. Aviagen Inc., Huntsville, AL.
  13. Temperature set points consisted of 34°C from placement to 4 d, 32°C from 5 to 9 d, 29°C from 10 to 14 d, 28°C from 15 to 19 d, 27°C from 20 to 24 d, 26°C from 25 to 29 d, 24°C from 30 to 34 d, 22°C from 35 to 39 d, 21°C from 40 to 43 d, and 19°C from 44 to 47 d; 16.5°C from 48 to 51 d; 15.5°C from 52 to 55 d; and 14°C from 56 to 60 d. Actual temperatures during 36 to 60 d from experiment 1 were as follows: 25.7°C ± 1.2 from 35 to 39 d; 22.6°C ± 2.5 from 40 to 43 d; 24.3°C ± 1.6 from 44 to 47 d; 20.5°C ± 1.7 from 48 to 51 d; 20.7°C ± 1.5 from 52 to 55 d; and 20.6°C ± 1.4 from 56 to 60 d. Actual temperatures during 36 to 60 d from experiment 2 were as follows: 17.4°C ± 1.2 from 48 to 51 d; 17.5°C ± 2.1 from 52 to 55 d; and 14.0°C ± 1.7 from 56 to 60 d.
  14. Lighting schedule consisted of continuous lighting with an intensity of 20 lx from placement to 7 d, 19L:5D, and an intensity of 20 lx from 8 to 14 d, 20L:4D, with an intensity of 5 lx from 15 to 22 d, and continuous lighting with an intensity of 3 lx from 23 to 60 d.
  15. Llames, C., and J. Fontaine. 1994. Determination of amino acids in feeds: Collaborative study. J. AOAC Int. 77:1362–1402.[ISI]
  16. AOAC. 1995. Official Methods of Analysis, Official Method 982.30, Section E (A, B, C). 16th ed. AOAC Int., Washington, DC.
  17. Ajinomoto Heartland. 2004. True Digestibility of Essential Amino Acids For Poultry Revision 7. Heartland LLC, Chicago, IL.
  18. Ibendahl, G. A., J. D. Anderson, and L. H. Anderson. 2004. Deciding when to replace an open beef cow. Agric. Finance Rev. 64:61–74.
  19. Johnson, D., and W. Lin. 2005. The economics of testing for biotech grain: Application to starlink corn. J. Agric. Resour. Econ. 20:268–284.
  20. Nehring, R. C., Barnard, D. Banker, and V. Breneman. 2006. Urban influence of costs of production in the corn belt. Am. J. Agric. Econ. 88:930–946.
  21. Experiment 1: total feed cost/bird (sum of the starter, grower, WDI, and WD2 periods) for the 4 dietary regimens was as follows: HH = $1.001; HL = $0.985; ML = $0.976; and LL = $0.977; Experiment 2: total feed cost/bird (sum of the starter, grower, WDI, and WD2 periods) for the 4 dietary regimens was as follows: H = $1.175; M = $1.168; L = $1.160; and S = $1.167.
  22. SAS Institute. 2004. SAS User’s Guide: Statistics. Version 9.1 ed. SAS Inst. Inc., Cary, NC.
  23. Tesseruad, S., N. Maaa, R. Peresson, and A. M. Chagneau. 1996. Relative responses of protein turnover in three different skeletal muscles to dietary skeletal muscles to dietary lysine deficiency in chicks. Br. Poult. Sci. 37:641–650.[ISI][Medline]



This article has been cited by other articles:


Home page
 J. Appl. Poult. Res.Home page
W. A. Dozier III, M. T. Kidd, and A. Corzo
Dietary Amino Acid Responses of Broiler Chickens
J. Appl. Poult. Res., January 1, 2008; 17(1): 157 - 167.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Summary Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Dozier, W. A.
Right arrow Articles by Branton, S. L.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Dozier, W. A., III
Right arrow Articles by Branton, S. L.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS