The nonprotein amino acid γ-aminobutyric acid (GABA) can enhance intestinal function in piglets; however, the mechanisms involved are not yet fully understood. To explore the effects of GABA and its underlying mechanisms, weanling piglets were randomly assigned to three groups, receiving either a basal diet or a basal diet supplemented with GABA (80 mg/kg or 120 mg/kg). The results demonstrated that dietary GABA improved growth performance and reduced diarrhea incidence (p < 0.05). Additionally, GABA supplementation decreased the serum and intestinal levels of pro-inflammatory cytokines (p < 0.05), and improved intestinal morphology. Multi-omics analyses were employed to explore the alterations caused by GABA supplementation and elucidate the related mechanisms. Microbiota profiling revealed improved beta-diversity and changes in the composition of ileal bacteria and fungi. Amino acid metabolism, lipid metabolism, and digestive processes were primarily enriched in the GABA group according to metabolomics analysis. A transcriptome analysis showed significant enrichment in ion transmembrane transport and nutrition absorption and digestion pathways in the ileum. Furthermore, increased lipase and trypsin activity, along with the elevated expression of tight junction proteins confirmed the beneficial effects of GABA on intestinal nutrient metabolism and barrier function. In conclusion, dietary 80 mg/kg GABA supplementation improved nutrient digestion and absorption and intestinal function in weanling piglets.

Serine is widely involved in antioxidant synthesis, immune response, and fat metabolism. However, it remains unclear whether dietary serine supplementation affects fat deposition in the skeletal muscles of pigs. Thus, we explored the effects of dietary serine supplementation on growth performance, meat quality, and composition of gut microbes and their metabolites in growing–finishing pigs. Forty-eight boars weighing approximately 20 kg were fed either a basal diet or a basal diet supplemented with 0.15% serine. The results showed that dietary serine increased the daily weight gain of pigs and improved serum antioxidant capacity as indicated by the decreased malondialdehyde content and increased glutathione and superoxide dismutase content. Pigs supplemented with serine had better meat quality, as shown by the lower drip loss and higher IMF content. Furthermore, dietary serine increased the relative abundance of Streptococcus and Lactobacillus and decreased the relative abundance of Clostridium_sensu_stricto_1 and Terrisporobacter. Differential microbial metabolites were mostly enriched in metabolic pathways related to lipid synthesis, such as alpha-linolenic acid metabolism and steroid hormone biosynthesis. Correlation analysis showed that the altered metabolites were closely related to the intestinal microbiota. In conclusion, our results suggested that serine serves as a potential additive for improving IMF content in growing–finishing pigs.

The coordination between the endoplasmic reticulum (ER) and mitochondria is increasingly recognized as a central regulator of skeletal muscle metabolism and, consequently, meat quality. Here, we summarize recent progress on how ER–mitochondrial communication regulates muscle metabolism and meat-quality traits. This interaction, primarily mediated by mitochondria-associated membranes, integrates key cellular processes, including calcium signaling, redox homeostasis, lipid metabolism, and cellular stress responses. These events then lead to tissue-level outcomes such as intramuscular fat deposition, transitions in muscle fiber types, and postmortem apoptotic or proteolytic events, all of which influence meat quality. However, comparative studies across livestock species reveal notable gaps and inconsistencies, highlighting the need for deeper mechanistic investigation. Overall, deepening our understanding of ER–mitochondria crosstalk will inform nutritional or molecular strategies to enhance meat quality and clarify species-specific regulatory mechanisms.