Transcriptome Analysis of the Effects of Compound Microecological Preparation on Chickens Challenged with Newcastle Disease Virus

Newcastle disease (ND), a highly contagious poultry disease caused by NDV, primarily triggers gastrointestinal lesions. Microecological preparations, novel biological additives for restoring intestinal microbiota diversity, improve nutrient absorption, reinforce intestinal barrier function, and modulate host immune responses. This study investigated the effects of a compound microecological preparation on intestinal pathogenicity in chickens infected with genotype VII Newcastle disease virus (NDV). SPF chickens were allocated to four dietary groups with or without a compound microecological preparation, followed by NDV challenge in two groups. Survival, intestinal morphology, and transcriptomic responses were assessed. The results showed that chickens fed with the compound microecological preparation exhibited improved intestinal development. Following NDV infection, these chickens displayed milder cecal lesions without obvious hemorrhage and a higher survival rate. Furthermore, differential gene transcription analysis revealed that supplementation with the compound microecological preparation regulated the expression of genes associated with metabolic processes, biological regulation, immune response, and growth and development pathways, consistent with the clinical findings. In conclusion, we demonstrated that the compound microecological preparation promotes intestinal development in chickens, delays disease progression following NDV infection, and alleviates pathological damage. Transcriptomic analysis further indicated that the preparation enhances intestinal mucosal immunity by stimulating IgA production and strengthening the immune response against genotype VII NDV. These findings provide a scientific basis for the application of compound microecological preparations in regulating the intestinal immune system and in the prevention of Newcastle disease.