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Keywords

amino acid, growth, lysine requirements, finishing pigs

Abstract

The objective of this study was to determine the standardized ileal digestible (SID) Lys requirement for growth and carcass performance of 225- to 280-lb finishing pigs. A total of 253 pigs (DNA 600 × 241, initially 224.9 lb BW) were used in a 23-d trial. Pens were blocked by BW and were randomly assigned to diets with 7 or 8 pigs per pen and 8 pens per treatment in a randomized complete block design. Diets were corn and soybean meal-based and fed in meal form. Dietary treatments consisted of 0.45, 0.55, 0.65, or 0.75% SID Lys. Increasing SID Lys increased (quadratic, P < 0.05) ADG and ADFI, resulting in pigs fed 0.55% SID Lys having the greatest final BW. A marginal significant improvement (quadratic, P < 0.10) was observed in F/G and caloric efficiency with increasing SID Lys. A marginal significant increase in carcass yield (linear, P < 0.10) and reduction (quadratic, P < 0.10) in backfat was also observed with increasing SID Lys. Carcass ADG increased (linear, P < 0.05) and carcass G:F was marginally improved (quadratic, P = 0.063), resulting in pigs fed 0.55% SID Lys having the greatest HCW. Furthermore, there was a marginal significant improvement (quadratic, P = 0.053) in carcass caloric efficiency on NE basis with increasing SID Lys. For ADG, quadratic polynomial (QP) model resulted in the best fit (BIC = 361.7) predicting 95, 98, and 100% of maximum growth at 0.50, 0.55, and 0.62% SID Lys, respectively. The QP and broken line linear (BLL) models had a comparable fit for F/G (BIC = 278.2 vs. 279.3, QP and BLL, respectively) with the QP model predicting 95, 98, and 100% of maximum feed efficiency at 0.48, 0.54, and 0.63% SID Lys, respectively. The BLL model predicted no further improvement in F/G over 0.55% SID Lys. In summary, the SID Lys requirement to obtain 100% of maximum response in this experiment was 0.62 and 0.63% for ADG and feed efficiency, respectively.

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This work is licensed under a Creative Commons Attribution 4.0 License.

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