Effect of Replacing Corn with Rice on Growth Performance, Meat Quality, Gut Microbiota and Metabolites in Growing–Finishing Pigs

This study aimed to investigate the effects of partially replacing corn with rice in the diet and supplementing with cellulase on growth performance, pork quality, and gut microbiota of growing-finishing pigs. A total of 64 healthy pigs (68.03 ± 1.59 kg) were randomly assigned into four groups: CON (basal diet), ASE (basal diet + 20,000 IU/g cellulase), RICE (the basal diet replaced 50% of corn with rice), RASE (the basal diet replaced 50% of corn with rice + 20,000 IU/g cellulase). The results indicated that dietary rice and cellulase, either individually or in combination, had no significant effects (<i>p</i> > 0.05) on the FBW, ADG, ADFI, and F/G of pigs. However, the dietary rice markedly increased the intramuscular fat (IMF) content (<i>p</i> < 0.05). Furthermore, gut microbiota profiling indicated that <i>Papillibacte</i> were enriched in the RICE group and positively associated with IMF content. Metabolomic analysis revealed substantial differences in fecal metabolites among the treatment groups. The RICE group exhibited reduced levels of Zygadenine, Carpaine, and Rhodioloside E, which were negatively correlated with both IMF content and <i>Papillibacter</i>. In conclusion, dietary rice can promote IMF deposition by modulating gut microbiota and host metabolism, without compromising the growth performance of pigs.