Table 1.
Genetic parameters (h 2=heritability; ρ g=genetic correlation with RFI; σ g=genetic SD; σ p=phenotypic SD), responses to selection 1 in generation G9 at the genetic level in the low RFI (LRFI) and high RFI (HRFI) lines and significance level of the difference (P)
| Traits | h 2 | ρ g | σ g | σ p | HRFI | LRFI | P 2 |
|---|---|---|---|---|---|---|---|
| Index (point) | 0.13 | 6.63 | 18.60 | 11.00 (0.27) | −14.10 (0.27) | *** | |
| RFI (g/day) | 0.13 | 42.93 | 119.56 | 73.88 (1.71) | −91.03 (1.71) | *** | |
| FCR | 0.42 | 0.39 | 0.13 | 0.20 | 0.15 (0.01) | −0.17 (0.01) | *** |
| DFI (g/day) | 0.41 | 0.25 | 127.63 | 199.85 | 146.22 (6.18) | −123.67 (6.18) | *** |
| ADG (g/day) | 0.50 | −0.07 | 54.12 | 76.45 | 10.53 (2.71) | 2.31 (2.71) | * |
| DP (%) | 0.36 | 0.05 | 1.06 | 1.76 | −0.50 (0.05) | 0.49 (0.05) | *** |
| Loin weight (kg) | 0.54 | 0.15 | 0.42 | 0.57 | −0.38 (0.02) | 0.33 (0.02) | *** |
| Ham weight (kg) | 0.51 | 0.09 | 0.32 | 0.45 | −0.24 (0.02) | 0.07 (0.02) | *** |
| Shoulder weight (kg) | 0.38 | 0.06 | 0.28 | 0.45 | −0.15 (0.01) | 0.16 (0.01) | *** |
| Backfat weight (kg) | 0.43 | −0.08 | 0.30 | 0.46 | 0.13 (0.02) | −0.14 (0.02) | *** |
| Belly weight (kg) | 0.28 | 0.11 | 0.21 | 0.39 | 0.23 (0.01) | −0.17 (0.01) | *** |
| LMCcalc (%) | 0.59 | 0.14 | 2.02 | 2.64 | −1.72 (0.10) | 0.92 (0.10) | *** |
| carcBFT (mm) | 0.40 | 0.02 | 2.40 | 3.80 | −0.23 (0.12) | −0.32 (0.12) | |
| pH 24 h AD | 0.41 | 0.28 | 17.06 | 26.57 | 14.69 (0.86) | −9.01 (0.86) | *** |
| pH 24 h SM | 0.38 | 0.22 | 12.03 | 19.48 | 12.90 (0.60) | −8.08 (0.60) | *** |
| pH 24 h GS | 0.39 | 0.23 | 10.84 | 17.31 | 12.36 (0.53) | −9.08 (0.53) | *** |
| pH 24 h LM | 0.32 | 0.19 | 10.41 | 18.50 | 9.99 (0.48) | −5.13 (0.48) | *** |
| L* GM | 0.20 | −0.14 | 1.59 | 3.55 | −0.24 (0.07) | 0.36 (0.07) | *** |
| L* GS | 0.33 | −0.17 | 2.13 | 3.71 | −2.27 (0.09) | 1.83 (0.09) | *** |
| a*_GM | 0.29 | −0.09 | 1.26 | 2.34 | 0.05 (0.06) | −0.43 (0.06) | *** |
| a*_GS | 0.26 | 0.12 | 0.88 | 1.73 | 0.09 (0.04) | −0.02 (0.04) | t |
| b*_GM | 0.24 | −0.12 | 0.80 | 1.65 | −0.02 (0.04) | −0.09 (0.04) | |
| b*_GS | 0.32 | −0.08 | 0.84 | 1.48 | −0.55 (0.04) | 0.41 (0.04) | *** |
| WHC (s) | 0.04 | −0.29 | 10.11 | 48.22 | 3.80 (0.32) | −3.11 (0.32) | *** |
| MQI | 0.33 | 0.26 | 1.61 | 2.80 | 1.97 (0.08) | −1.44 (0.08) | *** |
Index=selection index; FCR=feed conversion ratio; RFI=residual feed intake; DFI=daily feed intake; ADG=average daily gain; LMCcalc=lean meat content of the carcass computed from a linear combination of cut weights; carcBFT=backfat thickness measured on carcass; DP=dressing percentage of cold carcass; pH 24 h: determined 24 h after slaughter; AD=adductor; SM=semimembranosus; GS=gluteus superficialis; LM=longissimus muscle; GM=gluteus medius; L*=lightness, a*=redness, b*=yellowness, measured 24 h after slaughter; WHC=water holding capacity; MQI=meat quality index.
Least square means (SE) of a linear model including the fixed effects of line, generation and the interaction line×generation applied to the estimated breeding values of the pigs tested in the two lines from G0 to G9 (n=1451 candidates to selection and 1629 slaughtered sibs).
2 P value for the difference between least square means of the LRFI and LRFI lines in generation G9, ***=P<0.001, *=0.01<P<0.05, t=0.05<P<0.10.