A Novel Elemental Nano-Selenium Improves Growth Performance and Meat Quality with Potentially Regulating Muscle...

Selenium (Se) is a vital trace element affecting muscle development and quality.

This study aimed to evaluate the effects of sodium selenite (SeNa), selenomethionine (SeMet), and elemental nano-selenium (SeNPs) on growth performance and meat quality and the underlying mechanisms in finishing pigs.

Finishing pigs (120 pigs/group) were fed with a basal diet [control group (CON), 0.108 mg Se/kg] or CON supplemented with 0.4 mg Se/kg SeNa, SeMet, or SeNPs. At week 6, the longissimus dorsi (LD) muscle was collected for meat quality, Se, redox status, metabolomics, and transcriptomics analysis.

Compared with the CON, the 3 forms of Se supplementation increased (P < 0.05) body weight gain (1.84%-6.07%) and reduced (P < 0.05) the feed/gain ratio (2.72%-4.89%) of pigs. Feed intake (0.97%) increased (P < 0.05) in the SeNPs group, but no significant change was observed in the SeNa and SeMet groups. SeNPs further improved (P < 0.05) these performances by 1.65%-4.16% compared with SeNa. Moreover, SeNPs and SeMet enhanced (P < 0.05) Se concentration, marbling, and color, but decreased (P < 0.05) drip loss in the LD muscle compared with those of CON and SeNa. Notably, SeNPs uniquely stabilized postmortem pH_{45 min} and pH_{24 h} and minimized drip loss compared with the other 3 groups. In addition, SeMet and (or) SeNPs increased (P < 0.05) triglyceride contents and the activities of glutathione peroxidase and thioredoxin reductase in LD muscle. Metabolomic and transcriptomic profiling showed that SeNPs reduced lipid metabolism-related pathways and were associated with coordinated regulation of muscle and adipose tissue development. Multiomics integration further identified the AMP-activated protein kinase (AMPK)-mechanistic target of rapamycin (mTOR) signaling pathway as a central regulatory network targeted by SeNPs, thereby contributing to improvements in growth performance and meat quality in finishing pigs.

Compared with SeNa or SeMet, SeNPs demonstrated a unique ability to improve growth performance, meat quality, and antioxidant status in finishing pigs, associated with regulating energy metabolism by activating the AMPK-mTOR regulatory network.