Dietary inositol supplementation improves meat quality by modulating amino acid metabolism and gut microbiota composition of finishing pigs

Intramuscular fat (IMF) content influences various meat quality traits, including tenderness, flavor, juiciness and nutritional value. This study aimed to investigate the effects of dietary inositol supplementation on meat quality, metabolic profiles, and gut microbiota composition of finishing pigs. A total of 144 finishing pigs (initial body weight 70.41 ± 0.78 kg) were randomly divided into control, 0.075%, 0.15%, and 0.3% inositol groups. The data showed that inositol increased backfat thickness at the 6th to 7th rib and 10th rib, IMF content, and improved tenderness (<i>P</i> ≤ 0.05, <i>n</i> = 8). Paralleling an increase in fat deposition, 0.3% inositol also increased the protein level of PPARγ in the subcutaneous fat (<i>P</i> ≤ 0.05) and longissimus thoracis (LT) muscle (<i>P</i> = 0.062). Inositol elevated the content of amino acids in LT muscle and enhanced amino acid metabolism of finishing pigs, including lysine degradation, tyrosine metabolism, and arginine and proline metabolism. The 16S ribosomal RNA (rRNA) sequencing showed that 0.3% inositol supplementation altered the profiles of microbes in the colon, particularly decreasing the abundance of Firmicutes (<i>P</i> < 0.01) and increasing the abundance of Bacteroidota (<i>P</i> ≤ 0.05). Correlation analysis showed that differential microbes had strong correlation with differential metabolites in serum, including amino acids. In conclusion, this study demonstrated that dietary inositol supplementation could effectively improve IMF content and tenderness of pork, enhance amino acid metabolism, and regulate gut microbiota composition of finishing pigs.