Effects of Eimeria challenge and dietary essential oil supplementation on the relative mRNA expression levels of intestinal tight junction proteins of broiler at 28 d of age (A: duodenum, B: jejunum, C: ileum, and n = 12 birds). a–c, A, BMeans not sharing the same subscripts were different at α = 0.05 significant level. The a–c subscripts distinguished interactive differences and the A and B subscripts distinguished the main effect.