Quantitative analyses of genes associated with mucin synthesis of broiler chickens with induced necrotic enteritis

Clostridial infection of the intestine can result in necrotic enteritis (NE), compromising production and health of poultry. Mucins play a major role in protecting the intestinal epithelium from infection. The relative roles of different mucins in gut pathology following bacterial challenge are unclear. This study was designed to quantify the expression of mucin and mucin-related genes, using intestinal samples from an NE challenge trial where birds were fed diets with or without in-feed antimicrobials. A method for quantifying mucin gene expression was established using a suite of reference genes to normalize expression data. This method was then used to quantify the expression of 11 candidate genes involved in mucin, inflammatory cytokine, or growth factor biosynthesis (IL-18, KGF, TLR4, TFF2, TNF-α, MUC2, MUC4, MUC5ac, MUC5b, MUC13, and MUC16). The only genes that were differentially expressed in the intestine among treatment groups were MUC2, MUC13, and MUC5ac. Expression of MUC2 and MUC13 was depressed by co-challenge with Eimeria spp. and Clostridium perfringens. Antimicrobial treatment prevented an NE-induced decrease in MUC2 expression but did not affect MUC13. The expression of MUC5ac was elevated in birds challenged with Eimeria spp./C. perfringens compared with unchallenged controls and antimicrobial treatment. Changes to MUC gene expression in challenged birds is most likely a consequence of severe necrosis of the jejunal mucosa.