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Effects of Dietary Lysine Level and Amino Acid Ratios on Nursery Pig Performance
Effects of Dietary Lysine Level and Amino Acid Ratios on Nursery Pig Performance
Monday, March 13, 2017
Grand Ballroom Foyer (Century Link Center)
A total of 2,268 pigs (PIC 327×L42, initially 7.3 kg BW) were used in a 28-d growth study with 54 pigs/feeder (experimental unit) and 6 replications/treatment. Pigs were randomly allotted to pens at weaning and fed a common starter diet for 8 d. Pens were then blocked by BW and allotted to 1 of 7 dietary treatments in a randomized complete block design. Treatments were arranged in a [2×3]+1 factorial with 2 levels of standardized ileal digestible (SID) Lys, low (1.25%) and high (1.35%), and 3 SID amino acid (AA) ratios relative to Lys (industry, 95% of maximum performance, and maximum performance), as well as a control (1.35% SID Lys). Industry ratios were 55% Met+Cys:Lys, 62% Thr:Lys, 18% Trp:Lys, 65% Val:Lys, and 52% Ile:Lys. Maximum diet ratios were 60% Met+Cys:Lys, 65% Thr:Lys, 21% Trp:Lys, 72% Val:Lys, and 52% Ile:Lys. The 95% ratios were formulated to target 95% of maximum performance and were 56% Met+Cys:Lys, 62% Thr:Lys, 19% Trp:Lys, 67% Val:Lys, and 52% Ile:Lys. Diets were formulated to Ile requirement with feed-grade Lys, Met, Thr, Trp, and Val added. The control contained less feed-grade AA (0.39% L-Lys HCl vs. 0.50-0.55% in other diets) and 5% fermented soy protein to achieve similar soybean meal level to high SID Lys diets. Experimental diets were formulated using analyzed AA for corn, soybean meal, and dried distillers grains with solubles and fed for 14 d in meal form. Pens were weighed and feed disappearance was measured on d 0, 7, and 14. Data were analyzed using PROC GLIMMIX. From d 0 to 14, feeding high Lys diets increased (P<0.001) ADG and G:F compared with low Lys diets with no evidence for differences in ADFI between Lys level. Furthermore, for ADG, maximum AA ratios improved (P<0.05) performance compared to industry ratios at low Lys, but not at high Lys levels. In conclusion, higher AA ratios were more critical in diets formulated below the Lys requirement of the pig.
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Low Lys |
High Lys |
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Probability, P < |
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Item: |
Control |
Industry AA |
95% AA |
Max AA |
Industry AA |
95% AA |
Max AA |
SEM |
Low vs. High Lys |
d 0 to 14 |
|
|
|
|
|
|
|
|
|
ADG, g |
369a,b |
346c |
361b,c |
370a,b |
379a |
384a |
362b |
6.9 |
0.001 |
ADFI, g |
451b |
451b |
467a,b |
465a,b |
461a,b |
472a |
456a,b |
9.2 |
0.692 |
G:F |
0.819a,b |
0.769c |
0.774c |
0.797a,b,c |
0.823a |
0.814a,b |
0.794b,c |
0.0099 |
0.001 |
a,b,c Means within a row with differing superscripts differ P<0.05. |
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