Chinese Herbal Medicine Compound Microecological Agent (C-MEA) Improves Egg Production Performance in Caged Laying Ducks via Microbiota–Gut–Ovary Axis

This study was conducted to investigate the effects of a Chinese herbal medicine compound microecological agent (C-MEA) on the egg production performance, ovarian follicle development, ovary transcriptome, and cecal microbiota of caged laying ducks. A total of 108 black Muscovy ducks (150 days old) were randomly divided into three groups for 30 days in a formal feeding trial. Compared with the control basic diet (Group C) and 16 g/kg C-MEA dosage (Group B), the 8 g/kg C-MEA dosage (Group A) increased egg production (average laying rate 69.35%) and follicle development (5~7 Fs, 6~7 LYFs, 11~13 SYFs) mass (<i>p</i> < 0.05). According to RNA-Seq, the ovaries' transcriptome among different dietary groups enriched six key pathways, including neuroactive ligand-receptor interaction, the PPAR signaling pathway, ECM-receptor interaction, focal adhesion, the adherens junction, and the FoxO signaling pathway, as well as 46 candidate key genes. According to 16S-Seq, the microbial diversity was significantly increased in Group A, and the genus abundances of <i>Sphaerochaeta</i> and <i>UCG-004</i> were significantly changed among different dietary groups (<i>p</i> < 0.05). Supplementation with C-MEA may optimize the cecal microflora and the interactions between the intestinal microflora and the host. The results from combining RNA-Seq and 16S-Seq demonstrated that the relationship between <i>Sphaerochaeta</i> and the hub gene cluster (<i>F2</i>, <i>KNG1</i>, <i>C5</i>, <i>PLG</i>, <i>F2RL1</i>, <i>FABP1</i>, and <i>GCG</i>) is the most prominent. In conclusion, the egg performance of caged laying ducks can be modulated through the microbiota-gut-ovary axis. Our findings provide new insights for improving gut health and reproductive performance of caged laying ducks.