Abstract:

This study aimed to identify key candidate genes and pathways in cardiac and pulmonary tissues that mediate the development of ascites syndrome in broiler chickens.Taking the sires of fast-growing white-feathered broilers at 33 days of age as the research materials, 5 roosters with ascites syndrome and 3 normal roosters were selected. The occurrence of ascites syndrome in the roosters was determined through necropsy and the measurement of blood biochemical indicators. The subjects were categorized into an ascites group (5 roosters) and a control group (3 roosters).The results of blood biochemical analysis indicated that hematocrit (HCT), hemoglobin (HGB), and granulocyte percentage (GRA) in the ascites group were significantly higher than those in the normal group (P < 0.01).The lymphocyte percentage (LYM) in the ascites group was significantly lower than that in the normal group (P < 0.01).Additionally, the partial pressure of carbon dioxide (PCO₂) and total calcium (Ca) levels were significantly elevated in the ascites group compared to the normal group (P < 0.01), while the base excess (Beb) content was significantly lower in the ascites group (P < 0.05).The results of HE staining showed that in the normal group, the myofibrils in the myocardial tissue were arranged neatly, with no evidence of blood cell deposition between cells. In the ascites group, myocardial fibers exhibited structural disarray, and a large number of blood cells were deposited between the myofibrils. Transcriptome analysis identified 969 differentially expressed genes (DEGs) in lung tissue, including 417 upregulated genes and 552 downregulated genes. In cardiac tissue, 809 DEGs were identified, comprising 397 upregulated genes and 412 downregulated genes. Pathway enrichment analysis revealed significant enrichment in processes such as the mitotic cell cycle, centromere complex assembly, oxygen binding, neuroactive ligand-receptor interaction, cell adhesion molecules, cellular senescence, extracellular matrix (ECM)-receptor interaction, and motor proteins. Genes associated with ascites syndrome in broiler chickens were selected from enriched pathways and validated using real-time quantitative PCR. The results showed that the expression trends of KIF20A, NUSAP1, HBAD, TFRC, and HBBA genes differed between the ascites and normal groups, consistent with transcriptome sequencing findings, and these genes could be regarded as important candidate genes for ascites syndrome in broilers.The study, utilizing transcriptome technology, has identified significant pathways and candidate genes related to the development of ascites syndrome in broiler chickens, providing important insights into the disease mechanism and prevention strategies.

Key words: broiler, ascites syndrome, transcriptome, differentially expressed genes