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Effect of Increasing Sid Trp:Lys Ratio on Growth Performance of Grower-Finisher Pigs

Wednesday, March 15, 2017: 11:15 AM
214 (Century Link Center)
Tsung-Cheng Tsai , Department of Animal Science, Division of Agriculture, University of Arkansas, Fayetteville, AR
HaeJin Kim , University of Arkansas, Fayetteville, AR
Xiaofan Wang , Department of Animal Science, Division of Agriculture, University of Arkansas, Fayetteville, AR
J. J. Chewning , Swine Research Services, Inc., Springdale, AR
Jason A. Apple , Department of Animal Science, University of Arkansas Division of Agriculture, Fayetteville, AR
John E. Thomson , Evonik Degussa Corp, Kennesaw, GA
Charles V. Maxwell , Department of Animal Science, Division of Agriculture, University of Arkansas, Fayetteville, AR
Using a 5-phase feeding regime, pigs (n=252) were fed either antibiotic-free, control diets formulated to meet 100% SID Lys requirements and an SID Trp:Lys of 18.5 or diets formulated to 93% SID Lys requirements and incorporating L-Trp at 2.5 percentage unit increments to achieve SID Trp:Lys of 13.5, 16.0, 18.5, 21.0, or 23.5 during phase 1 (25 to 39 kg), 3 (71 to 86 kg), and 5 (110 to 140 kg) to determine the optimum SID Trp:Lys requirements. All pigs received a common corn-SBM-CDDGS-based, antibiotic-free, nutrient-adequate diets during feeding phase 2 and 4, and 10 ppm ractopamine hydrochloride was included in all phase-5 diets. ADG, ADFI, and BW increased quadratically, with the greatest responses observed in pigs fed SID Trp:Lys of 21 during phase 1 and 3, while the greatest ADG and BW at 18.5 and greatest ADFI at 16.0 during phase 5. G:F was similar in phase 1 and 3, but increased linearly with greatest result showed in pigs fed 23.5 of SID Trp/Lys diet in phase 5. HCW increased quadratic in pigs fed to an SID Trp:Lys 16.0, but 10th rib fat depth and lean yield were similar among treatments. The optimum ADG was predicted to be 0.72, 0.75, 1.12 kg/d in pigs fed an SID Trp:Lys ratio of 18.2, 18.8 and 16.8 in phases 1, 3, and 5, respectively.

93% SID Lys

100% SID Lys

13.50%

16%

18.50%

21%

23.50%

18.50%

Linear

Quad.

Phase 1 ADG, kg/d

0.64

0.70

0.71

0.73

0.72

0.59

< 0.01

0.04

Phase 3 ADG, kg/d

0.65

0.72

0.74

0.75

0.70

0.80

0.26

0.07

Phase 5 ADG, kg/d

0.90

1.07

1.12

1.08

1.09

1.08

< 0.01

< 0.01

Phase 1 ADFI, kg/d

1.29

1.40

1.50

1.59

1.38

1.44

0.16

0.04

Phase 3 ADFI, kg/d

2.27

2.68

2.65

2.77

2.60

2.72

0.08

0.05

Phase 5 ADFI, kg/d

3.08

3.52

3.31

3.47

3.30

3.35

0.36

0.09

Phase 5 G:F

0.29

0.31

0.33

0.31

0.33

0.32

< 0.01

0.41

End of phase 1 BW, kg

37.76

39.09

39.25

39.73

39.48

36.67

< 0.01

0.04

End of phase 3 BW, kg

84.70

86.23

86.93

87.10

85.97

88.79

0.20

0.07

End of phase 5 BW, kg

134.50

140.21

141.39

139.89

139.87

141.70

0.02

0.01

HCW, kg

220.63

229.44

229.27

229.00

229.07

231.07

0.03

0.05

Lean, %

53.24

53.49

53.02

53.59

53.35

53.31

0.76

0.96

10th rib fat depth, mm

21.44

22.08

22.18

21.10

20.93

22.83

0.50

0.43