and environmental impact (Patience, 2012). The residual
feed intake (RFI), defined as the difference between observed
feed intake and that predicted on the basis of requirements
for maintenance and growth, is now considered
as a pertinent criterion to further improve feed efficiency
in pigs (Gilbert et al., 2007; Cai et al., 2008; Hoque et al.,
2009). Pigs selected for low RFI (the most efficient) eat less
and spend less time eating (Young et al., 2011).