Table 1.
Effects of RFI line and hygiene conditions on growth performance of pigs
| Line | Low RFI | High RFI | P values | |||||
|---|---|---|---|---|---|---|---|---|
| Hygiene | Good | Poor | Good | Poor | MSE | Line | Hygiene | LxH |
| Period 1 (n = 71) | ||||||||
| BW W0 | 27.9 | 28.0 | 24.7 | 25.0 | 3.2 | < 0.001 | 0.80 | 0.93 |
| BW W6 | 62.5 | 58.6 | 55.6 | 48.1 | 6.2 | < 0.001 | 0.006 | 0.23 |
| ADG | 808c | 717bc | 762b | 537a | 115 | < 0.001 | < 0.001 | 0.08 |
| Proportions of tissues | ||||||||
| SCAT | 5.0 | 4.7 | 5.0 | 4.7 | 0.7 | 0.91 | 0.18 | 0.96 |
| PRAT | 0.56 | 0.48 | 0.48 | 0.39 | 0.11 | 0.02 | 0.02 | 0.99 |
| Liver | 2.3 | 2.3 | 2.6 | 2.7 | 0.2 | 0.005 | 0.56 | 0.71 |
| LL | 5.5bc | 5.8c | 5.3ab | 5.1a | 0.4 | 0.002 | 0.75 | 0.07 |
| Period 2 (n = 35) | ||||||||
| BW W12 | 102.4 | 90.8 | 98.8 | 81.1 | 10.0 | 0.06 | 0.002 | 0.38 |
| End BW | 111.0 | 100.2 | 110.2 | 90.1 | 9.4 | 0.10 | < 0.001 | 0.17 |
| ADG | 888 | 774 | 959 | 832 | 147 | 0.21 | 0.02 | 0.88 |
| Proportions of tissues | ||||||||
| SCAT | 6.8 | 6.2 | 6.7 | 5.8 | 1.5 | 0.65 | 0.14 | 0.71 |
| PRAT | 0.86 | 0.87 | 0.92 | 0.67 | 0.22 | 0.31 | 0.15 | 0.11 |
| Liver | 1.61 | 1.72 | 1.98 | 2.11 | 0.17 | < 0.001 | 0.04 | 0.90 |
| LL | 5.7 | 5.6 | 5.5 | 5.3 | 0.6 | 0.20 | 0.39 | 0.53 |
Pigs from two lines divergently selected for low (LRFI) or high (HRFI) residual feed intake (RFI) were housed either in good or poor hygiene conditions during the first 6 weeks (W) after their transfer in growing-finishing pens (period 1, challenge). Half of these pigs were killed at week 6 (W6: n = 20 LRFI pigs in good conditions, n = 20 HRFI pigs in good conditions, n = 15 LRFI pigs in poor conditions, n = 16 HRFI pigs in poor conditions). Another half were placed in good hygiene conditions until slaughter at weeks 13 or 14 (period 2, recovery: n = 10 LRFI pigs from good conditions, n = 10 HRFI pigs from good conditions, n = 7 LRFI pigs from poor conditions, n = 8 HRFI pigs from poor conditions). Body weight (BW, kg) at week 0 (W0), 12 (W12) and just before slaughter (end BW) were individually assessed. Average daily gain (ADG, g/d) was calculated during the two periods. Tissues (LL: longissimus lumborum muscle; PRAT: perirenal adipose tissue, SCAT: subcutaneous adipose tissue) were weighed at slaughter, and expressed in proportion to BW. Letters (a,b,c) were added in case of interaction (LxH; P < 0.10) between hygiene (H) and RFI line (L), and means sharing a common letter did not differ. MSE: root mean standard error of the statistical model. Bold face highlights significant differences (P ≤ 0.05) between treatments, and when italicized, this denotes a trend (0.05 < P ≤ 0.10)