TLR4 and infection: To determine the change in MyD88, TLR2, TLR3, TLR4, TLR18, TLR22-1, TLR22-2 and TLR22-3 from S. prenanti after LPS infection at 12 and 24 h, the mRNA levels of the genes in the liver, head kidney, spleen and hindgut were quantified using qRT-PCR.