TLR4 and Diarrhea: In conclusion, benzoic acid, bacillus coagulans, and oregano oil combined supplementation could improve growth performance and alleviate diarrhoea of piglets challenged with ETEC via improving intestinal mucosal barrier integrity, which was possibly associated with the improvement of intestinal microbiota and the reduction of proinflammatory cytokines production via inhibition of TLR4 and NOD2 signaling pathways.