Effects of residual feed intake divergence on the productive performance, egg quality, meat quality, and gut...

Residual feed intake (RFI) is a critical trait for improving feed efficiency in poultry, yet its impact on native chicken production and gut microbiota remains understudied. The present study aimed to evaluate the effects of RFI divergence on the productive performance, egg quality, meat quality, and gut microbiota composition in Wannan Yellow chickens. A total of 580 chickens were selected for the experiment to derive RFI. After the RFI measurement period (140 to 196 days of age), 40 chickens with high RFI (HRFI, mean RFI = 10.15 g/d) and 40 chickens with low RFI (LRFI, mean RFI = -11.83 g/d) were selected for the study. The LRFI group exhibited significantly lower average daily feed intake (ADFI) and feed conversion ratio (FCR) (P < 0.05), alongside improved meat quality traits, including higher water-holding capacity and lower shear force (P < 0.05), without compromising body weight gain (P > 0.05). No significant differences were observed in egg quality traits, though LRFI group showed numerically higher egg weights (P = 0.067). The 16S rRNA sequencing revealed distinct compositional differences in the cecal microbiota between the HRFI and LRFI groups, as demonstrated by non-metric multidimensional scaling (NMDS) and ANOSIM (R = 0.132, P = 0.021). LEfSe analysis identified 11 differentially enriched bacterial genera between the HRFI and LRFI groups (LDA score > 2.0, P < 0.05). Five LRFI-enriched bacterial genera including Bifidobacterium, Lachnospiraceae_NC2004_group, Lachnospiraceae_NK4A136_group, Papillibacter and Prevotellaceae_UCG-001, were found to be negatively correlated with RFI (R = -0.359 ∼ -0.499), FCR (R = -0.105 ∼ -0.464), ADFI (R = -0.270 ∼ -0.651) and shear force (R = -0.102 ∼ -0.347), and positively correlated with water holding capacity (R = 0.031 ∼ 0.291), provided direct evidence of their functional roles in promoting feed utilization efficiency and meat quality. These findings highlight the intricate interplay between RFI, microbial composition, and host productivity, offering valuable insights for integrating microbiome-based strategies into native chicken breeding programs.