Introduction
Materials and methods
Animals and diets
Collection and preparation of serum samples
Serum hormones and mineral measurements
Chemical analyses of bones
RNA isolation
Quantitative real-time PCR (qRT-PCR)
Data analyses
Results
Piglet performance and feed conversion ratio
Item | Unit | Low | Medium | High | |||
---|---|---|---|---|---|---|---|
LSmean | SE | LSmean | SE | LSmean | SE | ||
Live weight (day 28) | kg | 8.4 | 0.4 | 8.4 | 0.4 | 8.4 | 0.4 |
Live weight (day 64) | kg | 23.2b
| 1.2 | 20.8b
| 1.2 | 15.7a
| 1.2 |
Daily feed intake (day 28–day 64) | g/day | 691b
| 28 | 622a,b
| 28 | 549a
| 28 |
Daily body weight gain (day 28–day 64) | g/day | 403b
| 29 | 368b
| 29 | 198a
| 29 |
FCR (day 28–day 64) | g/g | 1.6a
| 0.5 | 1.7a
| 0.5 | 3.4b
| 0.5 |
Diet-specific serum hormone levels and mineral measurements
Item | Unit | Low | Medium | High | |||
---|---|---|---|---|---|---|---|
LSmean | SE | LSmean | SE | LSmean | SE | ||
Calcitriol | pmol/l | 572.68c
| 26.61 | 392.42b
| 37.07 | 291.95a
| 26.61 |
Parathyroid hormone | pg/ml | 2.26a
| 2.46 | 6.19a,b
| 2.71 | 10.51b
| 2.30 |
T3
| ng/ml | 0.81b
| 0.08 | 0.82b
| 0.08 | 0.47a
| 0.08 |
T4
| ng/ml | 11.64 | 1.24 | 10.62 | 1.24 | 11.90 | 1.24 |
Cortisol | ng/ml | 114.76 | 11.52 | 122.45 | 11.48 | 123.98 | 11.52 |
Inorganic phosphorus | mg/dl | 10.02 | 0.50 | 10.45 | 0.49 | 10.61 | 0.50 |
Calcium | mg/dl | 9.61 | 0.29 | 9.64 | 0.29 | 9.51 | 0.29 |
Bone characteristics
Item | Unit | Low | Medium | High | |||
---|---|---|---|---|---|---|---|
LSmean | SE | LSmean | SE | LSmean | SE | ||
Femur length | cm | 12.7 | 0.6 | 12.8 | 0.7 | 12.2 | 0.5 |
DMfat free
| mg/g FM | 296a
| 19.6 | 345b
| 16.7 | 345b
| 14.0 |
Crude ash | mg/g DMfat free
| 417a
| 52.7 | 476a,b
| 51.5 | 487b
| 53.3 |
Calcium | mg/g DMfat free
| 171 | 14.8 | 208 | 53.9 | 210 | 36.7 |
Phosphorus | mg/g DMfat free
| 73.4 | 10.4 | 82.2 | 12.1 | 92.2 | 30.4 |
Calcium:phosphorus ratio | 2.4 | 0.4 | 2.6 | 0.9 | 2.5 | 1.0 |
Gene expression in re-/absorbing and excreting tissues
Tissue | Gene symbol | Low versus medium FC |
p
| Low versus high FC |
p
| Medium versus high FC |
p
| Copy numbera
| ||
---|---|---|---|---|---|---|---|---|---|---|
Min | Max | Mean | ||||||||
Duodenum | VDR | + 1.47 | 0.148 |
− 1.17 | 0.579 |
− 1.73 | 0.065 | 1599 | 4327 | 2709 |
Cyp24A1 |
− 5.69
|
0.049
|
− 4.09
|
0.044
| + 1.39 | 0.858 | 6 | 225 | 45 | |
CYP27A1 | + 1.06 | 0.884 | + 1.31 | 0.396 | + 1.24 | 0.514 | 2859 | 15 202 | 6949 | |
CYP27B1 | + 1.26 | 0.272 | + 1.05 | 0.820 |
− 1.20 | 0.379 | 8 | 31 | 16 | |
PTH1R | + 1.12 | 0.625 | + 1.03 | 0.904 |
− 1.09 | 0.706 | 16 | 92 | 47 | |
THRA | + 1.13 | 0.583 | + 1.16 | 0.458 | + 1.03 | 0.870 | 317 | 1098 | 598 | |
SLC34A1 | nd | nd | nd | nd | nd | nd | nd | nd | nd | |
SLC34A2 | nd | nd | nd | nd | nd | nd | nd | nd | nd | |
SLC34A3 |
− 1.13 | 0.662 |
− 2.47
|
0.032
|
− 2.18 | 0.095 | 84 | 762 | 268 | |
Jejunum | VDR | + 1.05 | 0.777 |
− 1.38 | 0.149 |
− 1.45 | 0.092 | 823 | 4604 | 2206 |
Cyp24A1 |
− 45.37
|
< 0.001
|
− 528.81
|
< 0.001
|
− 11.66
|
0.006
| 0 | 412 | 65 | |
CYP27A1 |
− 1.52 | 0.239 |
− 1.43 | 0.299 | + 1.07 | 0.876 | 35 | 769 | 313 | |
CYP27B1 | + 1.25 | 0.439 |
+ 1.86
|
0.015
| + 1.49 | 0.072 | 3 | 15 | 8 | |
PTH1R |
− 1.27 | 0.558 | + 1.45 | 0.217 | + 1.83 | 0.081 | 2 | 20 | 9 | |
THRA |
− 1.18 | 0.245 | + 1.23 | 0.092 |
+ 1.45
|
0.009
| 728 | 1843 | 1169 | |
SLC34A1 | nd | nd | nd | nd | nd | nd | nd | nd | nd | |
SLC34A2 | nd | nd | nd | nd | nd | nd | nd | nd | nd | |
SLC34A3 |
− 1.36 | 0.130 |
− 1.86
|
0.013
|
− 1.37 | 0.246 | 485 | 2698 | 1612 | |
Colon | VDR | + 1.08 | 0.673 |
− 1.17 | 0.449 |
− 1.26 | 0.248 | 722 | 2874 | 1602 |
Cyp24A1 | nd | nd | nd | nd | nd | nd | nd | nd | nd | |
CYP27A1 |
− 1.23 | 0.348 |
− 1.32 | 0.213 |
− 1.08 | 0.750 | 110 | 543 | 262 | |
CYP27B1 | + 1.94 | 0.077 |
+ 3.33
|
< 0.001
|
+ 1.72
|
0.014
| 12 | 74 | 34 | |
PTH1R | + 1.27 | 0.368 | + 1.49 | 0.116 | + 1.17 | 0.474 | 24 | 124 | 52 | |
THRA | + 1.21 | 0.155 |
+ 1.45
|
0.006
| + 1.20 | 0.111 | 533 | 1236 | 910 | |
SLC34A1 | nd | nd | nd | nd | nd | nd | nd | nd | nd | |
SLC34A2 | nd | nd | nd | nd | nd | nd | nd | nd | nd | |
SLC34A3 | + 1.29 | 0.242 | + 1.36 | 0.145 | + 1.06 | 0.761 | 10 | 33 | 18 | |
Kidney | VDR |
+1.93
|
0.001
|
+1.99
|
< 0.001
| + 1.03 | 0.781 | 547 | 2175 | 1240 |
Cyp24A1 | + 3.82 | 0.072 | + 1.74 | 0.613 |
− 2.19 | 0.175 | 17 | 5723 | 1248 | |
CYP27A1 |
− 1.57
|
0.006
|
− 1.61
|
0.005
|
− 1.02 | 0.913 | 467 | 2256 | 1194 | |
CYP27B1 |
− 2.01
|
<0.001
|
− 1.93
|
< 0.001
| + 1.05 | 0.803 | 517 | 3097 | 1274 | |
PTH1R | + 1.02 | 0.808 | + 1.02 | 0.805 | + 1.01 | 0.998 | 5379 | 10 662 | 8235 | |
THRA | + 1.07 | 0.444 |
+ 1.28
|
0.010
|
+ 1.19
|
0.048
| 957 | 1881 | 1265 | |
SLC34A1 | + 1.02 | 0.854 |
− 1.13 | 0.205 |
− 1.15 | 0.154 | 35 633 | 67 928 | 53 221 | |
SLC34A2 |
− 1.45 | 0.161 |
− 1.05 | 0.814 | + 1.38 | 0.234 | 3 | 19 | 9 | |
SLC34A3 |
− 1.12 | 0.154 |
− 1.22
|
0.020
|
− 1.09 | 0.286 | 696 | 1363 | 1054 |