Soy Isoflavone Improves Reproductive Performance and Antioxidant Capacity of Sows and Reshapes Colostrum-Derived Exosomal microRNA Profiles

Reproductive performance and serum antioxidant indices were evaluated, and colostrum-derived exosomes were isolated for small RNA sequencing and bioinformatic analysis. Results: Dietary soy isoflavone supplementation significantly increased the total number of piglets born, the number of live-born piglets, litter weight at birth, and litter weight at weaning, while shortening farrowing duration (P < 0.05). In addition, soy isoflavone significantly elevated serum total antioxidant capacity and catalase activity on lactation day 21 (P < 0.05).

Transmission electron microscopy, nanoparticle tracking analysis, and flow cytometry confirmed the successful isolation of colostrum-derived exosomes. Small RNA sequencing showed that most microRNAs ranged from 18 to 26 nucleotides, with a predominant peak at 22–23 nucleotides. Principal component analysis and differential expression analysis revealed that soy isoflavone markedly reshaped the microRNA cargo of colostrum-derived exosomes.

Functional enrichment analysis indicated that the predicted target genes of differentially expressed microRNAs were mainly involved in transcriptional regulation, kinase-mediated signaling, inflammatory responses, and metabolic pathways, including mitogen-activated protein kinase, Ras, Rap1, endocytosis, autophagy, and adherens junction pathways. Integrated network analyses further suggested coordinated regulation of inflammatory signaling and metabolic homeostasis.

Conclusions: Dietary soy isoflavone supplementation improved sow reproductive performance and antioxidant capacity, while reshaping colostrum-derived exosomal microRNA profiles and their associated regulatory networks. These findings provide a potential molecular basis for maternal–offspring integrated regulation.