RNA Sequencing-Based Transcriptome Analysis of Liver in Laying Hens Supplemented with Dietary Probiotic Bacillus Species and Prebiotic Yeast (Saccharomyces cerevisiae) Cell Walls.

Abstract

To investigate the impacts of dietary Bacillus-based probiotics and yeast-derived prebiotics on the hepatic transcriptome profile, 500 Hisex White laying hens were randomly allotted into five dietary treatments from 37 to 52 weeks of age: control; control + Bacillus subtilis; control + Bacillus subtilis and Bacillus licheniformis; control + Bacillus coagulans; and control + Saccharomyces cerevisiae yeast cell wall. Transcriptome analysis revealed a substantial number of differentially expressed genes exclusively between the control and prebiotic groups, identifying 2221 genes (FDR ≤ 0.05), with 980 genes upregulated (log₂ fold change 0.69 to 24.62) and 1241 downregulated (log₂ fold change -0.74 to -26.46). The top 10 upregulated KEGG pathways included protein export, glycerophospholipid metabolism, tryptophan metabolism, amino acid biosynthesis, alanine, aspartate, and glutamate metabolism, cofactor biosynthesis, propanoate metabolism, ABC transporters, 2-oxocarboxylic acid metabolism, and protein processing within the endoplasmic reticulum. In contrast, the most prominently downregulated pathways encompassed fructose and mannose metabolism, hedgehog signaling, PPAR signaling, Notch signaling, GnRH signaling, cell adhesion molecules, cytokine-cytokine receptor interactions, apelin signaling, glycosaminoglycan degradation, and RIG-I-like receptor signaling. These findings advance understanding of the hepatic transcriptomic response to yeast-derived prebiotics and identify key molecular pathways that could be targeted to enhance metabolic function in laying hens.