View Full Table | Close Full ViewTable 1.

Diet composition, Exp. 1 (as-fed basis)1

 
Item Basal diet
Ingredient, %
    Corn 58.09
    Soybean meal (46.5% CP) 25.20
    Spray-dried whey 10.00
    Soybean oil 1.00
    Monocalcium P (21% P) 1.10
    Limestone 0.90
    Salt 0.35
    Zinc oxide 0.25
    Trace mineral premix2 0.15
    Vitamin premix3 0.25
    l-Lys HCl 0.533
    dl-Met 0.220
    l-Thr 0.230
    l-Ile 0.100
    l-Val 0.160
    Gln 0.630
    Gly 0.630
    Phytase4 0.085
    Corn starch5 0.123
    l-Trp
    Total 100
Calculated analysis
    SID AA,6 %
    Lys 1.30
    Ile:Lys 60
    Leu:Lys 111
    Met:Lys 36
    Met and Cys:Lys 58
    Thr:Lys 64
    Trp:Lys 14.7
    Val:Lys 70
Total Lys, % 1.42
ME, kcal/kg 3,341
NE, kcal/kg 2,239
SID lysine:ME, g/Mcal 3.89
SID lysine:NE, g/Mcal 5.27
CP, % 20.4
Ca, % 0.72
P, % 0.64
Available P, % 0.47
1Diets were fed from 6.8 to 9.8 kg BW. Nutrient content was calculated on the basis of values from NRC (1998).
2Provided per kilogram of diet: 39.6 mg Mn from manganese oxide, 165 mg Fe from iron sulfate, 1,965 mg Zn from zinc sulfate, 16.5 mg Cu from copper sulfate, 0.30 mg I from calcium iodate, and 0.30 mg Se from sodium selenite.
3Provided per kilogram of diet: 11,020 IU vitamin A, 1,378 IU vitamin D3, 44 IU vitamin E, 4 mg vitamin K, 8 mg riboflavin, 28 mg pantothenic acid, 50 mg niacin, and 0.039 mg vitamin B12.
4Phyzyme 600 (Danisco Animal Nutrition, St. Louis, MO) provided 509 phytase activity ( FTU) per kilogram of diet, with a release of 0.10% available P.
5Feed-grade l-Trp was added at the expense of corn starch at 0%, 0.024%, 0.049%, 0.074%, 0.098%, and 0.123% of the diet to provide Trp:Lys ratios of 14.7%, 16.5%, 18.4%, 20.3%, 22.1%, and 24.0% to form the experimental treatments.
6SID = standardized ileal digestible.



View Full Table | Close Full ViewTable 2.

Diet composition, Exp. 2 (as-fed basis)1

 
SID Trp:Lys
Item Low (14.5%) High (24.5%)
Ingredient, %
    Corn 55.15 55.05
    Soybean meal (46% CP) 10.91 10.92
    DDGS 30.00 30.00
    Beef tallow 0.50 0.50
    Dicalcium phosphate (18.5% P) 0.50 0.50
    Limestone 1.48 1.48
    Salt 0.35 0.35
    Trace mineral premix2 0.100 0.100
    Vitamin premix3 0.125 0.125
    l-Lys HCL 0.575 0.575
    dl-Met 0.070 0.070
    l-Thr 0.140 0.140
    l-Trp 0.098
    l-Ile 0.010 0.010
    l-Val 0.060 0.060
    Phytase4 0.025 0.025
    Total 100 100
Calculated analysis
    SID AA, %
    Lys 0.97 0.97
    Ile:Lys 55 55
    Leu:Lys 153 153
    Met:Lys 35 35
    Met and Cys:Lys 60 60
    Thr:Lys 65 65
    Trp:Lys 14.5 24.5
    Val:Lys 70 70
    His:Lys 38 38
    Phe and Tyr:Lys 106 106
    Trp:BCAA5 3.9 6.6
    Trp:LNAA6 2.8 4.8
ME, kcal/kg 3,325 3,328
NE, kcal/kg 2,466 2,468
SID lysine:ME, g/Mcal 2.91 2.91
SID lysine:NE, g/Mcal 3.93 3.93
CP, % 18.1 18.2
Ca, % 0.71 0.71
P, % 0.49 0.49
Available P, % 0.40 0.40
1Diets were fed from 11.2 to 20.3 kg BW. Corn, dried distillers grains with solubles (DDGS), and soybean meal were analyzed for CP and total AA content, and NRC (2012) standardized ileal digestible (SID) digestibility values were used in the diet formulation.
2Provided per kilogram of diet: 33 mg Mn from manganese oxide, 110 mg Fe from iron sulfate, 110 mg Zn from zinc oxide, 16.5 mg Cu from copper sulfate, 0.33 mg I from ethylenediamin dihydroiodide, and 0.30 mg Se from sodium selenite.
3Provided per kilogram of diet: 5,290 IU vitamin A, 827 IU vitamin D3, 26.4 IU vitamin E, 2.64 mg vitamin K, 16.5 mg pantothenic acid, 30 mg niacin, 4.6 mg riboflavin, and 0.02 mg vitamin B12.
4OptiPhos 2000 (Enzyvia LLC, Sheridan, IN) provided 1,251 phytase activity (FTU) per kilogram of diet with a release of 0.13% available P.
5Amount of Trp in the diet as a ratio to branched-chain AA (BCAA; Ile, Leu, and Val) on an SID basis.
6Amount of Trp in the diet as a ratio to large neutral AA (LNAA; Ile, Leu, Val, Phe, and Tyr) on an SID basis.



View Full Table | Close Full ViewTable 3.

Chemical analysis of the diets, Exp. 1 (as-fed basis)1

 
Standardized ileal digestible Trp:Lys2
Item 14.7% 16.5% 18.4% 20.3% 22.1% 24.0%
Proximate analysis, %
    DM 91.07 (89.43) 91.06 (89.43) 91.23 (89.43) 91.12 (89.43) 91.17 (89.43) 91.21 (89.43)
    CP 20.2 (20.4) 20.5 (20.4) 20.3 (20.4) 20.4 (20.4) 20.6 (20.5) 21.0 (20.5)
    CF 2.2 (2.3) 2.2 (2.3) 2.3 (2.3) 2.3 (2.3) 2.4 (2.3) 2.3 (2.3)
    Ca 0.87 (0.72) 0.85 (0.72) 0.76 (0.72) 0.84 (0.72) 0.86 (0.72) 0.87 (0.72)
    P 0.69 (0.64) 0.63 (0.64) 0.67 (0.64) 0.70 (0.64) 0.73 (0.64) 0.77 (0.64)
    Fat 3.3 (3.7) 3.2 (3.7) 3.4 (3.7) 3.1 (3.7) 3.2 (3.7) 3.2 (3.7)
    Ash 6.04 (5.54) 5.93 (5.54) 5.71 (5.54) 5.81 (5.54) 6.10 (5.54) 6.11 (5.54)
AA, %
    Lys 1.43 (1.42) 1.43 (1.42) 1.42 (1.42) 1.38 (1.42) 1.37 (1.42) 1.42 (1.42)
    Ile 0.90 (0.87) 0.95 (0.87) 0.93 (0.87) 0.94 (0.87) 0.91 (0.87) 0.93 (0.87)
    Leu 1.61 (1.61) 1.63 (1.61) 1.60 (1.61) 1.60 (1.61) 1.53 (1.61) 1.60 (1.61)
    Met 0.50 (0.50) 0.46 (0.50) 0.49 (0.50) 0.47 (0.50) 0.49 (0.50) 0.49 (0.50)
    Met and Cys 0.82 (0.82) 0.78 (0.82) 0.81 (0.82) 0.78 (0.82) 0.80 (0.82) 0.81 (0.82)
    Thr 0.95 (0.93) 0.97 (0.93) 0.95 (0.93) 0.94 (0.93) 0.94 (0.93) 0.95 (0.93)
    Trp 0.22 (0.22) 0.23 (0.24) 0.24 (0.26) 0.27 (0.29) 0.30 (0.31) 0.30 (0.34)
    Val 1.07 (1.02) 1.05 (1.02) 1.04 (1.02) 1.05 (1.02) 1.03 (1.02) 1.05 (1.02)
    His 0.47 (0.48) 0.46 (0.48) 0.46 (0.48) 0.45 (0.48) 0.44 (0.48) 0.46 (0.48)
    Phe 0.92 (0.86) 0.92 (0.86) 0.91 (0.86) 0.90 (0.86) 0.88 (0.86) 0.89 (0.86)
1Diet samples were collected from feeder at the beginning of the trial and on d 7 and 14. At the end of the trial, samples of each diet were combined, and a composite sample was analyzed for total AA analysis by Ajinomoto Heartland Inc. (Chicago, IL). Samples of the diets were also submitted to Ward Laboratories Inc. (Kearney, NE) for analysis of DM, CP, CF, Ca, P, ash, and crude fat.
2Values in parentheses indicate those calculated and are based on values from NRC (1998).



View Full Table | Close Full ViewTable 4.

Chemical analysis of the diets, Exp. 2 (as-fed basis)1

 
Standardized ileal digestible Trp:Lys2
Item 14.5% 16.5% 18.0% 19.5% 21.0% 22.5% 24.5%
Proximate analysis, %
    DM 90.48 (88.26) 90.06 (88.27) 90.21 (88.27) 90.25 (88.27) 90.35 (88.27) 89.91 (88.27) 89.78 (88.28)
    CP 19.0 (18.1) 19.4 (18.2) 18.8 (18.2) 18.7 (18.2) 18.9 (18.2) 19.1 (18.2) 18.2 (18.2)
    CF 3.8 (4.2) 3.8 (4.2) 4 (4.2) 3.9 (4.2) 3.5 (4.2) 3.8 (4.2) 4.0 (4.2)
    Ca 0.88 (0.71) 0.93 (0.71) 0.97 (0.71) 1.11 (0.71) 1.04 (0.71) 1.10 (0.71) 1.25 (0.71)
    P 0.52 (0.49) 0.52 (0.49) 0.55 (0.49) 0.54 (0.49) 0.52 (0.49) 0.53 (0.49) 0.54 (0.49)
    Fat 4.8 (5.2) 4.7 (5.2) 4.9 (5.2) 4.9 (5.2) 4.7 (5.2) 4.7 (5.2) 4.7 (5.2)
    Ash 4.89 (4.73) 4.75 (4.73) 4.82 (4.73) 5.39 (4.72) 5.35 (4.72) 5.18 (4.72) 5.57 (4.72)
AA, %
    Lys 1.19 (1.13) 1.18 (1.13) 1.22 (1.13) 1.22 (1.13) 1.17 (1.13) 1.16 (1.13) 1.19 (1.13)
    Ile 0.73 (0.65) 0.75 (0.65) 0.75 (0.65) 0.75 (0.65) 0.74 (0.65) 0.76 (0.65) 0.77 (0.65)
    Leu 1.82 (1.74) 1.86 (1.74) 1.86 (1.74) 1.87 (1.74) 1.85 (1.74) 1.90 (1.74) 1.89 (1.74)
    Met 0.40 (0.39) 0.39 (0.39) 0.40 (0.39) 0.40 (0.39) 0.40 (0.39) 0.39 (0.39) 0.40 (0.39)
    Met and Cys 0.70 (0.70) 0.71 (0.70) 0.72 (0.70) 0.71 (0.70) 0.72 (0.70) 0.72 (0.70) 0.73 (0.70)
    Thr 0.82 (0.78) 0.81 (0.78) 0.83 (0.78) 0.81 (0.78) 0.83 (0.78) 0.80 (0.77) 0.81 (0.77)
    Trp 0.19 (0.17) 0.19 (0.19) 0.19 (0.21) 0.20 (0.22) 0.23 (0.24) 0.23 (0.25) 0.24 (0.27)
    Val 0.93 (0.83) 0.96 (0.83) 0.96 (0.83) 0.96 (0.83) 0.95 (0.83) 0.96 (0.83) 0.96 (0.83)
    His 0.47 (0.44) 0.48 (0.44) 0.48 (0.44) 0.48 (0.44) 0.47 (0.44) 0.49 (0.44) 0.49 (0.44)
    Phe 0.88 (0.81) 0.91 (0.81) 0.90 (0.81) 0.91 (0.81) 0.90 (0.81) 0.93 (0.81) 0.93 (0.81)
1Diet samples were taken from 6 feeders per dietary treatment 3 d after the beginning of the trial and 3 d before the end of the trial and were stored at −20°C; then CP and AA analysis was conducted on composite samples by Ajinomoto Heartland Inc. (Chicago, IL). Samples of the diets were also submitted to Ward Laboratories Inc. (Kearney, NE) for analysis of DM, CF, Ca, P, ash, and crude fat.
2Values in parentheses indicate those calculated and are based on values from NRC (2012), with the exception of CP and total AA content from corn, soybean meal, and dried distillers grains with solubles , which were analyzed before diet formulation by Ajinomoto Heartland Inc. (Chicago, IL).



View Full Table | Close Full ViewTable 5.

Least squares mean estimates (±SEM) for growth performance of 6- to 10-kg nursery pigs fed dietary treatments consisting of standardized ileal digestible (SID) Trp:Lys ratios ranging from 14.7% to 24.0% (Exp. 1)1

 
SID Trp:Lys
Probability P
Item 14.7% 16.5% 18.4% 20.3% 22.1% 24.0% Linear Quadratic
ADG, g 226 ± 14.1 244 ± 8.5 244 ± 8.5 266 ± 14.1 258 ± 14.1 260 ± 8.5 <0.022 <0.484
ADFI, g 325 ± 11.6 342 ± 11.6 342 ± 11.6 349 ± 11.6 341 ± 11.6 363 ± 11.6 <0.057 <0.939
G:F 0.718 ± 0.011 0.697 ± 0.011 0.694 ± 0.011 0.750 ± 0.011 0.751 ± 0.011 0.716 ± 0.011 <0.012 <0.500
BW, kg
    d 0 6.3 ± 0.06 6.3 ± 0.06 6.2 ± 0.06 6.3 ± 0.06 6.2 ± 0.06 6.3 ± 0.06 <0.753 <0.870
    d 14 9.4 ± 0.19 9.7 ± 0.19 9.7 ± 0.09 10.0 ± 0.19 9.9 ± 0.19 9.9 ± 0.19 <0.052 <0.294
SID Trp intake, g/d 0.621 ± 0.029 0.736 ± 0.029 0.818 ± 0.029 0.917 ± 0.029 0.978 ± 0.029 1.132 ± 0.029 <0.001 <0.687
SID Trp g/kg gain 2.8 ± 0.11 3.0 ± 0.06 3.4 ± 0.06 3.5 ± 0.11 3.8 ± 0.11 4.4 ± 0.11 <0.001 <0.075
1A total of 255 nursery pigs (PIC 327 × 1050, initially 6.3 kg and 3 d postweaning) were used in a 14-d trial with 6 to 7 pigs per pen and 7 pens per treatment.
2Diets were formulated to 1.30% SID Lys based on data of Nemechek et al. (2011). The SID Trp intake and gram per kilogram gain were evaluated using diet calculated values for Trp.



View Full Table | Close Full ViewTable 6.

Least squares mean estimates (±SEM) for growth performance of 11- to 20-kg nursery pigs fed dietary treatments of standardized ileal digestible (SID) Trp:Lys ratio ranging from 14.5% to 24.5% (Exp. 2)1

 
SID Trp:Lys
Probability, P
Item 14.5% 16.5% 18.0% 19.5% 21.0% 22.5% 24.5% Linear Quadratic
d 0 to 21
    ADG, g 369 ± 20.2 428 ± 20.2 442 ± 20.2 432 ± 20.2 453 ± 17.6 451 ± 17.6 435 ± 17.6 <0.001 <0.001
    ADFI, g 682 ± 35.2 735 ± 31.1 759 ± 35.2 749 ± 35.2 768 ± 31.1 773 ± 31.1 750 ± 31.1 <0.001 <0.006
    G:F 0.543 ± 0.008 0.582 ± 0.005 0.582 ± 0.005 0.578 ± 0.008 0.590 ± 0.005 0.584 ± 0.005 0.580 ± 0.008 <0.002 <0.002
BW, kg
    d 0 11.3 ± 0.55 11.3 ± 0.55 11.2 ± 0.55 11.2 ± 0.55 11.2 ± 0.55 11.3 ± 0.55 11.2 ± 0.55 <0.844 <0.952
    d 21 19.0 ± 0.87 20.2 ± 0.87 20.7 ± 0.87 20.3 ± 0.94 20.8 ± 0.87 20.7 ± 0.87 20.4 ± 0.87 <0.001 <0.001
SID Trp intake, g/d 0.959 ± 0.069 1.176 ± 0.063 1.325 ± 0.069 1.417 ± 0.069 1.564 ± 0.063 1.686 ± 0.063 1.783 ± 0.063 <0.001 <0.026
SID Trp, g/kg gain 2.6 ± 0.04 2.8 ± 0.02 3.0 ± 0.02 3.3 ± 0.04 3.5 ± 0.04 3.7 ± 0.04 4.1 ± 0.04 <0.001 <0.006
1A total of 1,088 pigs (PIC 337 × 1050, initially 11.2 kg BW and 28 d postweaning) were used in a 21-d growth trial with 24 to 27 pigs per pen and 6 pens per treatment. The NRC (2012) model was used to determine the Lys requirement of mixed-gender pens of pigs at the end of the BW range (22.7 kg), and that value was reduced by 0.10%. The SID Trp intake and gram per kilogram gain were evaluated using diet calculated values for Trp.



View Full Table | Close Full ViewTable 7.

Standardized ileal digestible (SID) Trp:Lys ratio at different target performance levels of nursery pigs1

 
Percentage of maximum performance
Item 95% 96% 97% 98% 99% 100%
Exp. 1 (6- to 10-kg BW pigs)
ADG
    QP 18.1 18.7 19.4 20.2 21.3 23.9
G:F
    BLL 14.3 15.5 16.7 18.0 19.2 20.4
Exp. 2 (11- to 20-kg BW pigs)
ADG
    QP 17.6 18.0 18.4 18.9 19.6 21.2
G:F
    BLL 15.1 15.4 15.7 16.0 16.3 16.6
    BLQ 14.9 15.1 15.4 15.7 16.1 17.1
1Derived from equations presented in the text. BLL = broken-line linear; BLQ = broken-line quadratic; QP = quadratic polynomial.