PRL and pertussis: The KEGG pathway revealed that the developmental genes of circRNAs were concentrated in a variety of pathways including intestinal immune network for IgA production, pertussis pathway, prolactin pathway, salmonella infection, Toll like receptor pathway, ECM receptor interaction, MAPK signalling pathway and PI3K-Akt signaling pathway, NF kappa B signalling pathway, and cell adhesion molecules (Tables S4 and S5).