Crosstalk between liver gene expression and enteric microbiome regulates laying performance and lipid metabolism in different breeds of layer hens during growing and pre-laying periods

The present work was conducted to investigate the interaction between liver gene profile and enteric microbiome on regulation of laying performance and lipid metabolism in different breeds of layer hens during the growth and pre-laying periods. A total of 192 7-w-old laying hens (six replicates per breed, 16 hens per replicate), including 96 Jingfen-1 (JF-1) and 96 Jingfen-2 (JF-2) hens, were selected and fed the same feed under identical environments. The experiment lasted from 7 to 20 w-of-age. JF-1 initiated egg production at 16 w, whereas JF-2 started at 18 w. From 17 w, JF-1 exhibited higher egg production rates than JF-2 (P < 0.05). ​ Compared with JF-2, egg weight, Haugh unit, egg shape index, albumen height, and yolk mass were higher in JF-1 eggs (P < 0.05). Hepatic triglyceride, cholesterol, fatty acid synthase, and acetyl-CoA carboxylase contents were higher, whereas lipoprotein lipase and total lipase levels were lower in JF-1 (P < 0.05). There were 363 downregulated and 385 upregulated genes in the liver of the JF-2. Kyoto Encyclopedia of Genes and Genomes analysis indicated that pathways enriched in the downregulated genes of JF-2 hens included fatty acid biosynthesis, elongation, and metabolism and peroxisome proliferator-activated receptor signaling. Lipid synthesis-related genes such as FASN, ACACA, ELOVL2, and ACSL5 were upregulated in JF-1 hens. The cecal Firmicutes abundance in JF-1 was higher, whereas the Bacteroidetes abundance was lower than that in JF-2 hens (P < 0.05). Firmicutes/Bacteroidetes ratio in the cecum of JF-1 hens was higher than in JF-2 hens (P < 0.05). Phocaeicola, Lactobacillus, Mediterraneibacter, and Phascolarctobacterium were more abundant (P < 0.05) in the cecum of JF-1 hens. Correlation analysis suggested that higher Firmicutes/Bacteroidetes ratio in the cecum might activate the liver gene expression associated with lipid synthesis, and then improved egg quality in JF-1 hens. Summary, the liver genes and intestinal flora coordinated to promote laying performance and egg quality by modulating physiological fat deposition in JF-1 during the growing and pre-lay periods.