Effect of carvacrol essential oils on immune response and inflammation-related genes expression in broilers challenged by lipopolysaccharide

ABSTRACT This experiment was conducted to study the effects of orally administered carvacrol essential oils on immune response and inflammation-related genes expression in broilers challenged by lipopolysaccharide (LPS). Eighty 28-day-old (1.28 ± 0.15 kg) ROSS 308 broilers were assigned to a 2 × 2 factorial arrangement of treatments (20 pens of 1 chick/trt). Factors were carvacrol essential oil (orally administered or non-orally administered) and LPS (challenged or non-challenged). Individually housed broilers were randomly assigned (n = 20 broilers per treatment: 10 males and 10 females) to four treatments: (1) basic diet (CTR), (2) basic diet + carvacrol (CAR), (3) basic diet + LPS-challenge (LPS), (4) basic diet + carvacrol + LPS-challenge (CAR+LPS). All were fed with the same diet. The experimental period was for 15 d, after which injecting LPS significantly up-regulated the gene expression levels of TNF-α (P