Challenges with different Clostridium perfringens strains alter the expression of genes encoding proteins for apoptosis, mucin production and tight junction in broilers

The impact of two different strains of Clostridium perfringens (Cp) (NE-18 and NE-36) on mRNA expression of genes encoding proteins involved in cell apoptosis, intestinal tight junction and production of immunoglobulins and mucin in broiler chickens was investigated. A total of 468 male Ross 308 broilers was assigned to a 2 x 3 factorial arrangement of treatments. Factors were antibiotics (+/-), necrotic enteritis (NE) and challenge (-/ NE-18/ NE-36). A significant interaction between antibiotic treatment and challenge was observed on the expression of gene CASP3 (P < 0.05); NE-18 upregulated CASP3 only in the presence of antibiotics, while NE-36 upregulated this gene regardless of antibiotic supplementation. Interestingly, both NE strains upregulated CASP8 compared to the control treatment, but NE-36 showed higher CASP8 expression than observed with the NE-18 treatment (P < 0.001). It was shown that challenge significantly downregulated OCLD (P < 0.001), ZO-1 (P < 0.05) and MUC2 (P < 0.001). CLDN1 was significantly upregulated (P < 0.001) by both the NE-36 and NE-18 challenge, but NE-36 showing comparatively greater effects compared to NE-18. A significant antibiotic × challenge interaction on MUC5ac was observed (P < 0.05), where both NE- 18 and NE-36 upregulated MUS5ac when antibiotics was applied, but only NE-36 showed such upregulation in the absence of antibiotics. IgG and IgM were significantly downregulated (P < 0.001) by both strains of Cp. These results indicate that NE challenge alters the expression of genes investigated and different strains of Cp have varying impacts, which has a direct impact on severity of the disease.