Effects of Feeding High-Moisture Corn on Meat Performance, Meat Quality, Muscle Metabolism, and Gut Microbiota in Kazakh Rams

This study investigated the effects of feeding High-Moisture Corn (HMC) on meat production performance, mutton quality, muscle metabolism, and gut microbiota in Kazakh rams. Thirty-two 6-month-old Kazakh rams were divided into a control group (CT) and an experimental group (GS). Both groups received a basal diet consisting of 30% whole-plant corn silage, 30% cotton residue, and a concentrate mixture. In the CT group, the concentrate contained 24% ordinary crushed corn (on a dry matter basis). In the GS group, half of the ordinary crushed corn was replaced with HMC, resulting in a concentrate containing 12% ordinary crushed corn and 12% HMC. After a 120-day feeding period, backfat thickness was significantly higher in the GS group (p < 0.05); For meat quality, muscle shear force was significantly lower (p < 0.01) and intramuscular fat content was significantly higher (p < 0.01) in the GS group; Amino acid analysis showed that aspartic acid content was significantly lower (p < 0.01), arginine and glutamine contents were significantly lower (p < 0.05), and glycine content was significantly higher (p < 0.05) in the GS group; Fatty acid analysis revealed that the contents of methyl undecanoate, methyl myristate, methyl palmitate, methyl heptadecanoate, methyl alpha-linolenate, and all-cis-4,7,10,13,16-docosapentaenoic acid were significantly higher in the GS group (p < 0.01), while the contents of ten other fatty acids, including methyl caprate, methyl laurate, and methyl tridecanoate, were significantly higher (p < 0.05); A total of 668 metabolites were detected by muscle metabolomics, and 20 of them were identified as significantly differential metabolites, with the GS group showing 15 upregulated and 5 downregulated, mainly enriched in four pathways: valine, leucine and isoleucine biosynthesis; taurine and hypotaurine metabolism; pantothenate and CoA biosynthesis; and the citrate cycle (TCA cycle); Gut microbiota analysis showed no significant difference in alpha diversity, but beta diversity was significantly separated between the two groups (p < 0.01); Correlation analysis revealed that Firmicutes_A was significantly negatively correlated with most fatty acids, while Proteobacteria was significantly positively correlated with multiple fatty acids (p < 0.05). In conclusion, The GS group had significantly increased backfat thickness, reduced muscle shear force, increased intramuscular fat content, and significantly enriched beneficial fatty acids in Kazakh rams, thereby improving meat quality.