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Journal of Animal Science Abstract - Animal Genetics

Genetics of residual feed intake in growing pigs: Relationships with production traits, and nitrogen and phosphorus excretion traits1


This article in JAS

  1. Vol. 91 No. 6, p. 2542-2554
    Received: July 27, 2012
    Accepted: Mar 01, 2013
    Published: November 25, 2014

    2 Corresponding author(s):

  1. R. Saintilan 2,
  2. I. Mérour33,
  3. L. Brossard§#,
  4. T. Tribout*†,
  5. J. Y. Dourmad§#,
  6. P. Sellier*†,
  7. J. Bidanel,
  8. J. van Milgen§# and
  9. H. Gilbert*†║¶
  1. INRA, UMR1313, GABI, F-78352 Jouy-en-Josas Cedex, France
    AgroParisTech, UMR1313, GABI, F-75231 Paris Cedex, France
    IFIP- Institut du porc, F-35651 Le Rheu Cedex, France
    INRA, UMR1348, PEGASE, F-35590 Saint Gilles Cedex, France
    Agrocampus Ouest, UMR1348, PEGASE, F-35000 Rennes Cedex, France
    INRA, UMR444, LGC, F-31326 Castanet-Tolosan Cedex, France
    INP, UMR444, LGC, F-31029 Toulouse Cedex, France


Residual feed intake (RFI) is defined as the difference between the observed ADFI and the ADFI predicted from production and maintenance requirements. The objectives of this study were to evaluate RFI as a selection criterion to improve feed efficiency and its potential to reduce N and P excretion in 4 pig breeds. Data were collected between 2000 and 2009 in French central test stations for 2 dam breeds [French Landrace (LR) and Large White (LWD)], and 2 sire breeds [Large White (LWS) and Piétrain (PP)]. Numbers of recorded pigs were 6407, 10,694, 2342, and 2448 for the LR, LWD, LWS, and PP breeds, respectively. All PP animals were genotyped for the halothane mutation. This data set was used to calculate RFI equations for each of the 4 breeds, and to estimate genetic parameters for RFI together with growth, carcass, and meat quality traits, and N and P excretion during the test period (35 to 110 kg BW). The RFI explained 20.1% in PP, 26.5% in LWS, 27.6% in LWD, and 29.5% in LR of the phenotypic variability of ADFI. The PP breed differed from the others in this respect, probably due to a lower impact of the variation of body composition on ADFI. Heritability estimates of RFI ranged from 0.21 ± 0.03 (LWD) to 0.33 ± 0.06 (PP) depending on the breed. Heritabilities of N and P excretion traits ranged from 0.29 ± 0.06 to 0.40 ± 0.06. The RFI showed positive genetic correlations with feed conversion ratio (FCR) and excretion traits, these correlations being greater in the sire breeds (from 0.57 to 0.86) than in the dam breeds (from 0.38 to 0.53). Compared with FCR, RFI had weaker genetic correlations with carcass composition, growth rate, and excretion traits. Estimates of genetic correlations between FCR and excretion traits were very close to 1 for all breeds. Finally, excretion traits were, at the genetic level, correlated positively with ADFI, negatively with growth rate and carcass leanness, whereas the halothane n mutation in PP was shown to reduce N and P excretion levels. To conclude, new selection indexes including RFI can be envisaged to efficiently disentangle the responses to selection on growth rate and body composition from those on feed efficiency, with favorable impacts on N and P excretions, particularly in sire pig breeds. However, the switch from FCR to RFI in selection indexes should not resolve the genetic antagonism between feed efficiency and meat quality.

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