Lactobacillus acidophilus fermentation product modulates inflammatory activity by regulating the TLR4 and NFkB expression in porcine peripheral blood mononuclear cells after lipopolysaccharide challenge

Abstract Text: A total of forty weaned pigs [(Landrace x Yorkshire) x Duroc] were used to evaluate the effects of Lactobacillus acidophilus fermentation product (LAFP; SynGenX^®, Diamond V, Cedar Rapids, IA) on inflammatory activity after lipopolysaccharide (LPS) challenge. Experimental treatments were T1) control diet + saline challenge; T2) control diet with 0.1% LAFP + saline challenge; T3) control diet + LPS challenge; T4) control diet with 0.1% LAPF + LPS challenge. The BW of individual pig was recorded at the beginning and d-14 and feed consumption was recorded on an individual pig basis during the experiment to calculate ADG, ADFI and G/F. On days 14 of the trial, piglets were challenged with saline (T1 and T2) or LPS (T3 and T4). Blood samples were obtained at 0, 2, 4, 6, and 12h after challenged and analyzed cytokine production and gene expression pattern. Serum insulin-like growth factor 1 (IGF-1), cortisol, tumor necrosis factor alpha (TNF-α), and IL-6 were determined by ELISA. For peripheral blood mononuclear cells (PBMCs) isolation, the collected blood (with an equal volume of balanced salt solution) was mixed with a half volume of Histopaque solution, and was then centrifuged at 400 x g for 35min at room temperature. The PBMCs were carefully aspirated from the Histopaque solution-plasma interface. The LAPF treatment increased BW, ADG, and ADFI compared to the control diet. With control diet, the LPS challenge (T3) increased immune cells and expression of TNF-α and IL-6 compared to saline challenge (T1). Whereas with saline challenge, LAPF treatment (T2) increased WBCs and CD4⁺ compared to the control diet (T1). With LPS challenge, LAPF treatment (T4) decreased white blood cells, lymphocytes, CD4⁺, CD8⁺, and expression of TNF-α and IL-6 compared to the control diet (T3). LAPF treatment decreased expression of toll-like receptor 4 (TRL4) and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) in PBMCs after LPS challenge, which leads to inhibition of TNF-α, interferon gamma (IFNγ), IL-6, IL-8, and IL1B1 and to induction of IL-4 and IL-10. We suggested that LAPF improved ADG and ADFI and protected against LPS-induced inflammatory responses by regulating TLR4 and NFκB expression in porcine PBMCs.

Keywords: Lactobacillus acidophilus; lipopolysaccharide; peripheral blood mononuclear cells