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

## TL;DR

Replacing half of corn with rice in pig diets improves meat quality by increasing fat without affecting growth, likely through changes in gut microbes and metabolites.

## Contribution

This study demonstrates that rice can enhance pork quality by increasing intramuscular fat through gut microbiota and metabolite modulation.

## Key findings

- Replacing 50% of corn with rice increased intramuscular fat (IMF) without affecting growth performance.
- Rice-based diets enriched Papillibacter, which was positively linked to IMF levels.
- Metabolites like Zygadenine, Carpaine, and Rhodioloside E decreased in rice-fed pigs and were negatively correlated with IMF and Papillibacter.

## Abstract

Rice, a widely cultivated grain, has emerged as a promising alternative to corn, the primary energy source in conventional pig diets. However, the potential effects of replacing corn with rice on pig growth performance have not been fully assessed, and its influence on pork quality and underlying mechanisms remains unclear. This study examined the impact of replacing 50% of dietary corn with rice, with or without added cellulase, in growing–finishing pigs. We evaluated growth performance, gut microbiota, fecal metabolites, and pork quality. The results showed that replacing half of the corn with rice did not impair growth performance. Instead, it significantly increased intramuscular fat (IMF), a key indicator of meat quality. Rice-based diets also reshaped the gut microbiota and metabolite profiles. Notably, the abundance of Papillibacter increased and was positively associated with IMF levels, while several metabolites—including Zygadenine, Carpaine, and Rhodioloside E—decreased. These metabolites were negatively related to both Papillibacter and IMF, suggesting that modifications in the microbiota–metabolite axis may contribute to enhanced fat deposition. Overall, incorporating rice into pig diets improved pork quality by increasing IMF without compromising growth, supporting the use of rice as a promising feed ingredient.

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 (p > 0.05) on the FBW, ADG, ADFI, and F/G of pigs. However, the dietary rice markedly increased the intramuscular fat (IMF) content (p < 0.05). Furthermore, gut microbiota profiling indicated that Papillibacte 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 Papillibacter. In conclusion, dietary rice can promote IMF deposition by modulating gut microbiota and host metabolism, without compromising the growth performance of pigs.