Replacing dietary sodium selenite with biogenic selenium nanoparticles improves the growth performance and gut health of early-weaned piglets.

Selenium nanoparticles (SeNPs) are proposed as a safer and more effective selenium delivery system than sodium selenite (NaSeO). Here, we investigated the effects of replacing dietary NaSeO with SeNPs synthesized by ATCC 393 on the growth performance and gut health of early-weaned piglets. Seventy-two piglets ( ×  × ) weaned at 21 d of age were divided into the control group (basal diet containing 0.3 mg Se/kg from NaSeO) and SeNPs group (basal diet containing 0.3 mg Se/kg from SeNPs) during a 14-d feeding period. The results revealed that SeNPs supplementation increased the average daily gain ( = 0.022) and average daily feed intake ( = 0.033), reduced ( = 0.056) the diarrhea incidence, and improved ( = 0.013) the feed conversion ratio compared with NaSeO. Additionally, SeNPs increased jejunal microvilli height ( = 0.006) and alleviated the intestinal barrier dysfunction by upregulating ( < 0.05) the expression levels of mucin 2 and tight junction proteins, increasing ( < 0.05) Se availability, and maintaining mitochondrial structure and function, thereby improving antioxidant capacity and immunity. Furthermore, metabolomics showed that SeNPs can regulate lipid metabolism and participate in the synthesis, secretion and action of parathyroid hormone, proximal tubule bicarbonate reclamation and tricarboxylic acid cycle. Moreover, SeNPs increased ( < 0.05) the abundance of and the levels of acetate and propionate. Correlation analysis suggested that was closely associated with the regulatory effects of SeNPs on early-weaned piglets through participating in lipid metabolism. Overall, replacing dietary NaSeO with biogenic SeNPs could be a potential nutritional intervention strategy to prevent early-weaning syndrome in piglets.