Clostridium perfringens type A is the main etiological factor for necrotic
enteritis, a multifactorial enteric disease that penalizes performance, health, and welfare of poultry. Lack of knowledge of host responses and disease pathogenesis is slowing down progress on developing
therapies for disease control. A combined genomewide and targeted gene approach was used to investigate pathways and
biological functions affected by the infusion of C. perfringens culture supernatant in the duodenum of broilers in 2 experiments. An in situ isolated loop of duodenum was prepared in anesthetized broilers of 3 wk of age (Exp. 1) and was infused either with crude C. perfringens culture supernatant (n = 7; treated), positive for necrotic
enteritis B-like toxin (NetB) as determined by a cytotoxicity assay, or with a control preparation (n = 6; control). Birds were maintained alive for 1 h and then euthanized for tissue recovery. The use of the Affymetrix chicken genome array on
RNA samples from loop tissue showed top
biological functions affected by culture supernatant infusion included cell morphology, immune cell trafficking, and cell death; pathways affected included
death receptor signaling, inflammatory response, and nuclear factor (NF)-κB signaling. In a second in situ study (Exp. 2), broilers were maintained alive for 4 h to monitor temporal expression patterns of targeted genes. Duodenal tissue was removed at 0.5, 1, 2, and 4 h post-infusion with culture supernatant (n = 9) or a control preparation (n = 5) for histology and gene expression analysis. Genes encoding proinflammatory
cytokines, such as
interferon γ (IFNγ), cell trafficking, such as
neuroblastoma 1 (NBL1) and B cell CLL/
Lymphoma 6 (BCL6), and cell death, such as
Fas cell surface death receptor (FAS) and
GTPase IMAP family member 8 (GIMAP8), were differentially expressed in the duodenum of treated and control broilers (P < 0.05). We have demonstrated that C. perfringens culture supernatant (NetB positive) infusion resulted in histological and gene expression changes consistent with necrotic
enteritis in the duodenum of broilers. In the absence of live bacteria, crude culture supernatant resulted in early
immunomodulation,
inflammation, and cell death in the duodenum. The pathways identified here can be targeted for the development of new drugs,
vaccines, and novel
therapies for necrotic
enteritis in broilers.