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Effects of cation-anion balance in diets for newly weaned nursery pigs
This study was to determine effects of cation-anion differences (CAD, mEq = (Na+K)-(Cl+S)) on growth performance of nursery pigs. Newly weaned pigs (120 pigs with 6.83 ± 0.94 kg BW at 3 wk of age) were allotted to 4 treatments with varied levels of CAD (180, 110, 45, and -20 mEq, respectively in phase I and II diets; and 155, 95, 33, and -20, respectively in phase III diets) by supplementing Cad-mate (Granco Minerals, Petersburg, VA) to gradually decrease CAD. There were 10 pens per treatments assigned by 5 BW blocks and 2 sex blocks in a randomized complete block design. Pigs were fed the assigned experimental diets based for 5 wk in 3 phases (I: d 0 to 7; II: d 7 to 19; and III: d 19 to 33). Growth performance was measured by obtaining ADG, ADFI, and G:F for each phase. Serum samples were taken at d 33 to measure liver function. Fecal samples were collected at d 26 to measure DM. All data were analyzed using the PROC MIXED procedure of SAS (Ver. 9.3). Linear and quadratic contrasts were used to evaluate treatment effects. Decreasing CAD increased (P < 0.05) ADG in a quadratic manner in phase III. Overall, decreasing CAD increased (P < 0.05) ADG and G:F in a quadratic manner. Increasing Cad-mate supplementation also increased (P < 0.05) serum Cl in a linear manner. The DM of fecal tended to decrease (P= 0.081) linearly with decreasing CAD. Collectively, CAD influenced the performance of newly weaned pigs. Importantly, maintaining negative mEq of CAD in the diet improved the growth performance of nursery pigs.
CAD, mEq |
|
P-value |
|||||
Phase I and II / III |
180 / 155 |
110 / 95 |
45 / 33 |
-20 / -20 |
SEM |
Linear |
Quadratic |
ADG, kg/d |
|
|
|
|
|
|
|
Phase I |
0.094 |
0.099 |
0.124 |
0.128 |
0.027 |
0.115 |
0.970 |
Phase II |
0.338 |
0.308 |
0.328 |
0.339 |
0.024 |
0.751 |
0.197 |
Phase III |
0.472 |
0.449 |
0.415 |
0.502 |
0.022 |
0.501 |
0.006 |
Overall |
0.343 |
0.324 |
0.322 |
0.364 |
0.021 |
0.313 |
0.027 |
G:F |
|
|
|
|
|
|
|
Phase I |
0.672 |
0.597 |
0.685 |
0.773 |
0.191 |
0.289 |
0.320 |
Phase II |
0.719 |
0.699 |
0.672 |
0.716 |
0.028 |
0.738 |
0.206 |
Phase III |
0.594 |
0.593 |
0.563 |
0.608 |
0.013 |
0.834 |
0.088 |
Overall |
0.639 |
0.631 |
0.611 |
0.650 |
0.020 |
0.745 |
0.024 |
Serum Cl, mEq/L |
102.9 |
102.2 |
104.4 |
105.9 |
0.839 |
0.002 |
0.134 |
DM in fecal, % |
25.77 |
26.04 |
20.62 |
23.78 |
1.557 |
0.081 |
0.309 |
Keywords: cation-anion balance, growth performance, nursery pigs