Intramuscular fat (IMF) content serves as the key determinants of meat quality. Emerging evidence indicates that gut microbiota and their metabolites significantly influence IMF deposition levels by modulating host lipid metabolism through multiple pathways, positioning microbial regulation as a pivotal target for meat quality improvement. However, existing studies remain fragmented, predominantly focusing on isolated mechanisms or correlations without a systematic view of the regulatory network. This review consolidates the core mechanisms through which microbiota-derived metabolites including short-chain fatty acids, bile acids, branched-chain amino acids, trimethylamine N-oxide, tryptophan derivatives, succinate, polyamines etc., regulate IMF deposition and proposes a targeted intervention framework, the “gut microbiota/metabolites-IMF axis”. By integrating these insights, we provide a theoretical foundation and define practical research pathways to assess the potential of microbial-based strategies for improving meat quality in swine production.

As a prevalent mycotoxin found in cereal foods and feed, deoxynivalenol (DON) disrupts the orderly regeneration of intestinal epithelial tissue by interfering with the intracellular antioxidant defense system. However, the potential of mulberry leaf-derived Morin, a natural flavonoid active substance with clearing reactive oxygen species (ROS), to mitigate DON-induced intestinal oxidative damage remains unclear. Our investigation demonstrates that Morin effectively reverses the decline in growth performance and repairs damaged jejunal structures and barrier function under DON exposure. Furthermore, the proliferation and differentiation of intestinal stem cells (ISCs) is enhanced significantly after Morin intervention. Importantly, Morin increases the levels of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) in the serum and jejunal tissue, while reducing the accumulation of ROS and malondialdehyde (MDA). Molecular interaction analysis further confirms that Morin targets inhibition of Keap1 to activate the Nrf2-mediated antioxidant system. In summary, our results suggest that Morin alleviates the oxidative damage induced by DON by regulating the Keap1/Nrf2 pathway, thereby restoring the proliferation and differentiation activity of ISC, which provides new insights into Morin mitigating DON damage.

Prevotella and Segatella are important, keystone genera in the gut microbiota, renowned for their exceptional fiber-degrading capacity. These genera critically modulate gut microbial composition, influence host metabolic pathways and gut barrier function, and exhibit formidable ecological niche competitiveness, underscoring their pivotal role in gut ecosystem dynamics. While they dominate healthy gut microbiomes, their probiotic potential on epithelial barrier function has been disproportionately overlooked. This review comprehensively elucidates their microbial eco-profiling and the underlying molecular mechanisms in sustaining intestinal barrier function, considering physical, chemical, biological, and microbiological dimensions, thereby providing insights relevant to the prevention and treatment of intestinal diseases such as inflammatory bowel disease, irritable bowel syndrome, and metabolic disorders. Most importantly, we have summarized 23 current commercial and research-based isolation and cultivation approaches for Prevotella/Segatella, integrating the emerging high-throughput methodologies to expand the available strain repertoire. We also emphasize the critical need for subsequent research to characterize strain-specific functional profiles through multi-omics approaches, which will be essential for developing targeted and personalized microbial therapeutics.

There are different stress resistance among different breeds of pigs. Changes in intestinal stem cells (ISCs) are still unclear among various breeds of piglets after early weaning. In the current study, Taoyuan Black and Duroc piglets were slaughtered at 21 days of age (early weaning day) and 24 days of age (3 days after early weaning) for 10 piglets in each group. The results showed that the rate of ISC-driven epithelial renewal in local Taoyuan Black pigs hardly changed after weaning for 3 days. However, weaning stress significantly reduced the weight of the duodenum and jejunum in Duroc piglets. Meanwhile, the jejunal villus height, tight junction-related proteins (ZO-1, Occludin, and Claudin1), as well as the trans-epithelial electrical resistance (TEER) values, were down-regulated after weaning for 3 days in Duroc piglets. Moreover, compared with Unweaned Duroc piglets, the numbers of Olfm4⁺ ISC cells, PCNA⁺ mitotic cells, SOX9⁺ secretory progenitor cells, and Villin⁺ absorptive cells in the jejunum were reduced significantly 3 days after weaning. And ex vivo jejunal crypt-derived organoids exhibited growth disadvantages in weaned Duroc piglets. Notably, the Keap1/Nrf2 signaling activities and the expression of HO-1 were significantly depressed in weaned Duroc piglets compared to Unweaned Duroc piglets. Thus, we can conclude that ISCs of Duroc piglets were more sensitive to weaning stress injury than Taoyuan Black piglets, and Keap1/Nrf2 signaling is involved in this process.

Muscle regeneration, representing an essential homeostatic process, relies mainly on the myogenic progress of resident satellite cells, and it is modulated by multiple physical and nutritional factors. Here, we investigated how myogenic differentiation-related factors and pathways respond to the first limiting amino acid lysine (Lys) in the fast and slow muscles, and their satellite cells (SCs), of swine. Thirty 28-day-old weaned piglets with similar body weights were subjected to three diet regimens: control group (d 0–28: 1.31% Lys, n = 12), Lys-deficient group (d 0–28: 0.83% Lys, n = 12), and Lys rescue group (d 0–14: 0.83% Lys; d 15–28: 1.31% Lys, n = 6). Pigs on d 15 and 29 were selectively slaughtered for muscular parameters evaluation. Satellite cells isolated from fast (semimembranosus) and slow (semitendinosus) muscles were also selected to investigate differentiation ability variations. We found Lys deficiency significantly hindered muscle development in both fast and slow muscles via the distinct manipulation of myogenic regulatory factors and the Wnt/Ca²⁺ pathway. In the SC model, Lys deficiency suppressed the Wnt/Ca²⁺ pathways and myosin heavy chain, myogenin, and myogenic regulatory factor 4 in slow muscle SCs but stimulated them in fast muscle SCs. When sufficient Lys was attained, the fast muscle-derived SCs Wnt/Ca²⁺ pathway (protein kinase C, calcineurin, calcium/calmodulin-dependent protein kinase II, and nuclear factor of activated T cells 1) was repressed, while the Wnt/Ca²⁺ pathway of its counterpart was stimulated to further the myogenic differentiation. Lys potentially manipulates the differentiation of porcine slow and fast muscle myofibers via the Wnt/Ca²⁺ pathway in opposite trends.

Fiber, the most abundant organic polymer in nature, is widely recognized as a foundational sustainable material with diverse applications across industrial, medical, and consumer domains. Owing to its renewability and widespread availability, it also serves as a critical alternative energy source in agriculture, enabling more sustainable livestock production through the efficient conversion of fibrous feedstuffs, thereby supporting the principles of a circular bioeconomy. Cellulose, which constitutes up to 80% of plant fiber, contains tightly packed crystalline regions that confer strong resistance to microbial degradation. Other key obstacles to efficient cellulose digestion in the gut include the absence of critical cellulolytic genes, low enzymatic activity, a lack of natural activators, and the presence of cellulase inhibitors. Synthetic biology provides innovative molecular-level strategies to overcome key technical barriers in cellulose degradation. These approaches employ targeted modifications at nucleic acid and protein levels, including the introduction of engineered genes, synthetic regulators, and optimized enzymes, to develop high-performance microbial systems with enhanced cellulose-degrading capabilities. Furthermore, genetic modifications like the knockout of inhibitory genes and knock-in of activator genes, combined with rational redesign of multi-enzyme complexes, can significantly improve the secretion and catalytic efficiency of cellulases. When integrated with artificial intelligence, synthetic biology enables predictive screening and precision engineering of microbial strains for highly efficient cellulose degradation. This review comprehensively summarizes recent advances in synthetic biology approaches for improving cellulose degradation and highlights how these tools can optimize fiber utilization in sustainable agricultural and industrial applications.