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Effect of ractopamine and enzyme supplementation 28 days prior to marketing on growth performance of finishing pigs
One-hundred eighty pigs (initial BW=105.4 ± 1.29 kg) were used to evaluate the effects of two enzymes individually and in combination in a corn-soybean meal-cDDGS based diet on pig growth performance and feed efficiency during late finishing. Pigs were allocated in a randomized complete block design of mixed gender pens, stratified by ancestory, gender, and initial BW to 5 treatments with 6 pens/treatment and 6 pigs/pen. Dietary treatments included: 1) negative control (0.75% SID Lys; NC); 2) NC plus ractopamine (RAC); 3) RAC+enzyme (0.08 MU/kg β-mannanase; RENZ1); 4) RAC+enzyme (0.08 MU/kg β-glucanase + 0.10 MU/kg β-mannanase; RENZ2); 5) RAC+enzyme (0.08 MU/kg β-glucanase, 0.18 MU/kg β-mannanase; RENZ1+2). Treatments 2-5 contained 5 ppm ractopamine from d 0-14 and 10 ppm ractopamine from d 14-28. For d 0-14, pigs fed the RAC diet had increased (P<0.001) ADG, improved feed efficiency and tended (P<0.06) to have increased ADFI when compared to pigs fed the NC diet. Pigs fed RENZ1 had increased (P<0.05) ADG, and improved (P<0.02) G:F, while pigs fed RENZ2 tended (P<0.08) to have reduced G:F compared to pigs fed RAC. Pigs fed RAC from d 14-28 had increased (P<0.05) ADG, ADFI, and improved G:F compared to NC. Feeding RENZ1 or RENZ2 had no impact (P>0.61) on ADG, ADFI, or G:F from d 14-28 compared to RAC fed pigs. For the overall period d 0-28, pigs fed RAC diets had increased (P<0.04) ADG and ADFI with improved (P<0.001) feed efficiency compared to NC. Pigs fed RENZ1 had increased (P<0.01) ADG and improved (P<0.02) feed efficiency while pigs fed RENZ2 had no improvement (P>0.21) in measured response criteria compared to pigs fed RAC. In conclusion, pigs fed the RAC diet had increased ADG and ADFI with improved feed efficiency throughout the trial. Pigs fed RENZ1 had increased ADG driven by improved feed efficiency compared to pigs fed RAC. This study indicates the combination of RAC and β-mannanase has the potential to improve late finishing performance.
Table 1. Effect of Ractopamine and enzyme supplementation 28 days prior to marketing on growth performance of finishing pigs. |
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Treatment |
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|
NC |
RAC |
RENZ1 |
RENZ2 |
RENZ1+2 |
|
SEM |
|
1P < |
d 0 to 28 |
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ADG2, kg |
0.81 |
0.99 |
1.04 |
0.97 |
1.02 |
0.020 |
0.001 |
||
ADFI, kg |
3.10 |
3.24 |
3.25 |
3.26 |
3.25 |
0.053 |
0.04 |
||
G/F2 |
0.26 |
0.31 |
0.32 |
0.30 |
0.32 |
0.007 |
0.001 |
||
1 Main effect of Ractopamine (NC vs RAC). |
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2 RENZ1 improved (P<0.02) ADG and G:F. |
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Keywords: mannanase, glucanase, ractopamine