Assessment of Feed Efficiency and Its Relationship with Egg Quality in Two Purebred Chicken Lines and Their Reciprocal Crosses

Crossbreeding is normally applied to improve the economical traits of chickens. However, feed efficiency and its relationship with egg quality have rarely been explored in crossbreds. Herein, White Leghorn and Beijing You chickens were selected to generate purebreds (WW, YY) and reciprocal crossbreds (YW, WY), which were evaluated in terms of daily feed intake (DFI), feed conversion ratio (FCR), and residual feed intake (RFI) at 43 to 46 and 69 to 72 weeks of age, respectively. We found that WY was more efficient than YW in both laying periods. The correlation analysis showed that RFI was highly correlated with DFI (0.49 to 0.84) but unrelated to egg mass, and FCR was negatively correlated with egg mass (−0.77 to −0.43) in both purebreds and crossbreds. Moreover, RFI was not correlated with egg quality traits within each genetic group, except for the egg yolk ratio (0.27) in WW. FCR was negatively correlated with eggshell weight and thickness (−0.33 to −0.19) in WW and WY. Compared to FCR, selection for RFI could improve feed efficiency without significant changes in egg mass and quality in chickens. These findings provide new insights into the improvement of feed efficiency using rational parental lines in chicken crossbreeding.