Plant essential oil supplementation promotes growth and attenuates lipopolysaccharide (LPS)-induced acute liver injury through SIRT1/PGC-1α signaling pathway in nursery pigs

Objective: This study aimed to evaluate whether dietary supplementation with plant essential oil (PEO) and coated plant essential oil (CEO) could promote growth and alleviate liver oxidative damage in nursery piglets challenged with lipopolysaccharide (LPS) by modulating mitochondrial function in the liver. Methods: Twenty-four 21-day-old piglets were randomly assigned to four groups, with six replicates per group. The CON and LPS groups received a basal diet, while the LPS+PEO and LPS+CEO groups were received the basal diet supplemented with 500 mg/kg of PEO and 500 mg/kg of CEO, respectively. The experimental period lasted for 28 days. On day 49, piglets in the LPS, LPS+PEO, and LPS+CEO groups were injected intraperitoneally with LPS at a dose of 100 ㎍/kg body weight, while those in the CON group received an equal volume of saline. All piglets were weighed and euthanized four hours after the LPS or saline injection. Blood and liver samples were collected for further analysis. Results: Piglets in the LPS+PEO and LPS+CEO groups showed higher (p<0.05) average daily gain and better feed conversion ratio, and increased mRNA expressions of liver HO1, NQO1 and Trx2 compared to the LPS and CON groups. Diet supplemented with PEO and CEO increased (p<0.05) the contents of immunoglobulin A (IgA), immunoglobulin G and immunoglobulin M (IgM), and the protein expressions of SIRT1 and PGC-1α in the liver of LPS-induced nursery piglets. Furthermore, piglets in the LPS+CEO group exhibited higher (p<0.05) levels of IgA, IgM, total antioxidant capacity, and the mRNA expressions of SOD2 and Trx2 in the liver than those of the LPS+PEO group. Conclusion: Dietary supplementation with PEO or CEO improved growth performance in nursery piglets and alleviated LPS-induced liver oxidative damage in nursery piglets through activation of the SIRT1/PGC-1α signaling pathway. In addition, CEO supplementation demonstrated a more pronounced antioxidant effect than PEO.