Effects of Tributyrin on Antioxidant Capacity, Immune Function, and Liver Macrophage Polarization in Weaned Piglets...

Under intensive farming systems and the global ban on antibiotic growth promoters (AGPs), early-weaned piglets exhibit incomplete physiological development, increasing their susceptibility to stress-related liver dysfunction and growth performance impairments. This study first investigated the effects of dietary supplementation with 0.2% tributyrin on the growth performance of 21-day-old weaned piglets over a 28-day period. Subsequently, on the final day, we examined its influence on antioxidant capacity, immune responses, and liver macrophage polarization using a 2 × 2 factorial challenge model, with the factors being diet (basal or tributyrin-supplemented) and immunological challenge (saline or lipopolysaccharide). The experimental results indicated that tributyrin had a significant enhancement on the average daily gain (ADG) of weaned piglets within the 0-14-day period (p < 0.05). Under lipopolysaccharide (LPS) challenge, tributyrin significantly increased the levels of catalase (CAT) and interleukin-10 (IL-10) while reducing the levels of malondialdehyde (MDA) and interleukin-6 (IL-6) in both serum and liver. Additionally, it significantly increased glutathione peroxidase (GSH-pX) activity in the serum and reduced glutathione (GSH) levels in the liver, and also decreased the serum level of interleukin-1β (IL-1β). Tributyrin downregulated pro-inflammatory cytokine gene expression while upregulating anti-inflammatory cytokine expression (p < 0.05). Furthermore, tributyrin significantly inhibited the expression of M1 macrophage polarization markers while enhancing those of M2 polarization (p < 0.05). Additionally, tributyrin suppressed SIRT1/NF-κB signaling pathway activation and promoted JAK2/STAT6 signaling pathway activation (p < 0.05). These findings exhibit that tributyrin alters the polarization of liver macrophages by regulating the SIRT1/NF-κB and JAK2/STAT6 signaling pathways, enhances antioxidant and immune functions, reduces LPS-induced liver inflammatory damage, and improves the growth performance of weaned piglets.