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Super-dosed phytase improves rate and efficiency of gain in nursery pigs
Previous studies have shown that phytase fed at super-dosed levels may improve pig performance. However, the level of phytase used for super-dosing and the performance responses have been inconsistent. An experiment was conducted with newly weaned nursery pigs to determine if rate and efficiency of gain could be improved with a super-dose level of phytase and whether this response would be greater when energy and amino acids were limiting. Four hundred forty pigs (6.27 ± 0.29 kg) were assigned to pens on the basis of body weight, providing 11 pens of 10 pigs each per treatment. Pens were assigned to treatment according to a randomized complete block design. Treatments were arranged in a factorial design comparing the main effects of diet (positive control [PC] versus a negative control: 10% lower SID lysine with relative lowering of all other essential amino acids and 1% reduced fat [NC]) and phytase levels (0 vs 2,500 FTU Quantum Blue®). Feed and water were provided ad libitumacross 4 dietary phases: 3 ×1 wk plus 1 ×2 wk. Data were analyzed using the PROC MIXED procedure of SAS. For the overall experiment (Table), both diet and phytase were significant for ADG and G:F. However, ADFI was unaffected. There were no interactions. Not shown in the table, NC with 2500 FTU phytase resulted in ADG (0.459 vs 0.468) and G:F (0.691 vs 0.701) that were not different from that of the PC with no phytase (P< 0.05). In conclusion, feeding phytase at super-dosed levels in the nursery phase improves growth performance, irrespective of diet adequacy.
Item |
Main effect of diet1 |
Main effect of phytase |
P-values |
||||
|
PC |
NC |
0 |
2,500FTU |
Diet |
Phytase |
DXP |
BW, kg |
|
|
|
|
|
|
|
d0 |
6.28 |
6.26 |
6.27 |
6.27 |
0.10 |
0.72 |
0.72 |
d35 |
22.45 |
21.68 |
21.89 |
22.23 |
<0.01 |
0.14 |
0.34 |
ADG, kg/d |
0.477 |
0.456 |
0.461 |
0.472 |
<0.001 |
0.043 |
0.520 |
ADFI, kg/d |
0.676 |
0.685 |
0.681 |
0.681 |
0.186 |
1.000 |
0.893 |
Gain:feed |
0.706 |
0.667 |
0.678 |
0.695 |
<0.001 |
0.006 |
0.239 |
1 PC = Positive control; NC = negative control
Keywords: lysine, phytase, superdose,