Transcriptome of the ovaries and oviduct associates inflammatory response with high blood and meat spots incidence in chickens

Blood and meat spots in egg white and yolk are regarded as defects affecting egg internal quality. The presence of blood and meat spots in egg directly reflects the health status of the hen's ovary and oviduct. In this study, we analyzed mRNA and lncRNA profiles from 36 samples (ovary, magnum/isthmus, and uterus) collected from 12 Rhode Island Red hens with higher and lower incidence of blood and meat spots (BMS) in eggs, to elucidate the factors associated with BMS incidence. There were 398, 359, 548 differentially expressed genes (DEGs) and 194, 34, 170 differentially expressed lncRNAs (DElncRNAs) across the ovary, magnum/isthmus and uterus identified between high and low BMS incidence groups. Through WGCNA analysis, we identified phenotype-associated gene modules in the ovary, the key tissues where egg yolk formed, which indicated DEGs in the ovary was associated with BMS formation. Further analysis revealed 36, 28, 353 DEGs were co-expressed with DElncRNAs in the ovary, magnum/isthmus tissues, and uterus, respectively. Functional enrichment analysis indicated that co-expressed genes in ovary and magnum/isthmus were predominantly associated with inflammatory responses and immune regulation, which indicated inflammation response occurred in ovary tissue. Our study provided the transcriptome profiles of chickens with high and low BMS, which was helpful for in-depth research on molecular mechanisms underlying BMS formation.