Resveratrol alleviates stress-associated bursal injury in chickens: a transcriptomic analysis

1. Resveratrol (RSV) is an antioxidant and anti-inflammatory plant polyphenol that is widely used for the prevention of stress-related diseases. Chronic unpredictable mild stress (CUMS) significantly affects the immune system of layers, leading to substantial losses in growth performance and welfare. The aim of this study was to explore the effect of a multi-stress environment under CUMS conditions on the bursa of Fabricius and any therapeutic effects.2. A total of 288 healthy, one-day-old layer chicks were divided into three groups: a healthy control, challenged with CUMS or CUMS+RSV. At 42 d of age, bursa of Fabricius samples were collected and analysed. Transmission electron microscopy (TEM), haematoxylin and eosin (H&E) staining, RNA-seq technology, qRT-PCR, Western blots, immunofluorescence and immunohistochemical staining were used to assess tissue damage and mRNA expression and enrichment pathways.3. The tissue damage under CUMS challenge was observed and RSV alleviated the degree of injury from the results of H&E staining and TEM. Transcriptome analysis identified a total of 631, 293 and 598 differentially expressed genes (DEG; log2 fold change > 1, p < 0.05) in the control vs. CUMS, CUMS vs. CUMS+RSV and control vs. CUMS+RSV group, respectively.4. Genes related to neuroactive ligand–receptor interaction were NTSR1 and GZMA down-regulated while KNG1, OPRL1 and P2RY8 were up-regulated and calcium signalling pathway genes CXCR4, PLCG2, PRKCB and CAMK2A were up-regulated in the CUMS group compared to control group. However, CXCR4, PLCG2 and CAMK2A were down-regulated, whereas NTSR1 and GZMA were up-regulated genes in CUMS+RSV group compared to the CUMS group. Analyses of DEG was conducted based on the KEGG pathway and verified using qRT PCR and Western blots.