Moreover, Asp down-regulated the mRNA expression of toll-like receptor 4 (TLR4) and nucleotide-binding oligomerization domain protein (NOD) signaling-related genes, nuclear factor-κB (NF-κB) p65 and p38, decreased phosphorylation of jejunal p38, and increased phosphorylation of ileal extracellular signal-related kinase 1/2 linearly or quadratically.