Pork quality differences between lines divergently selected for residual feed intake
Résumé
Recent studies demonstrated that a selection for residual feed intake (RFI) led to improved feed conversion ratio and carcass lean meat content. However, the understanding of the relationships between RFI and pork quality is still unclear and deserves further study to meet producer, processing industry and consumer demands. Our objective was to evaluate the impact of a divergent selection on RFI on technological and sensory quality of meat. After six generations of selection, growth performance, carcass composition, muscle biochemical and meat quality traits were studied in 117 Large White females and castrated males from two divergent RFI lines fed ad libitum. Despite similar growth rate, the low RFI line (RFI-) pigs were more efficient (p<0.001), exhibited leaner carcasses (p<0.001) and a greater carcass yield (p<0.001) than high RFI line (RFI+) pigs. Selection for low RFI affected meat quality parameters by increasing muscle glycogen content (p<0.001) as well as the extent of pH decline (p<0.001) and drip loss (p<0.001), and decreasing IMF content (p<0.001) in the Longissimus muscle. Visual appearance of fresh meat was also influenced, with lower scores for marbling, homogeneity and intensity of red color of the RFI- pork. However, these differences between RFI lines had no effect on meat tenderness and juiciness. Regarding trade-offs between economical results for producers (lower feeding cost, higher carcass lean content) and environmental issues, the negative impact of selection for low RFI on pork quality could be moderated.