Effect of surfactin on growth performance of weaning piglets in combination with Bacillus subtilis BC1212

The aim of this study is to investigate the effects of surfactin in combination with Bacillus subtilis BC1212 isolated from Korean soybean paste, on feed utilization and growth performance during 4 weeks in weaning piglets. Eighteen weaning piglets (Landrace × Yorkshire × Duroc; weighing 7.68±0.97 kg) were divided into control (n=9) and experimental groups (n=9). The treatments included a control group consisting of the basal diet with no additives (control) and an experimental group consisting of the basal diet supplemented with 1 g of surfactin C and 1.0×10⁹ CFU of Bacillus subtilis BC1212/kg feed. Piglets fed Bacillus subtilis BC1212 increased in average daily weight gain and feed efficiency. In comparison with the control group, the fecal Bacillus subtilis were significantly increased and the fecal coliform bacteria were markedly reduced in the experimental group. In addition, Bacillus subtilis BC1212 had excellent acid and bile tolerance. The treatment of surfactin (50 μg ml^-1) in lipopolysaccharide (LPS)-stimulated swine peripheral blood mononuclear cells (PBMCs) for 6 h showed a significant inhibitory effect on INF-γ, TNF-α and NO secretion (p<0.05) in comparison with LPS treatment alone but not on IL-10 secretion, with levels of secreted IL-10 similar to those secreted by PBMCs stimulated with LPS alone. Supplementation with surfactin in combination with Bacillus subtilis BC1212 in diets improved the ecosystem of gastrointestinal tract by increasing probiotic population and enhanced the systemic immune response in weaned piglets.