The hyper-prolificacy Meishan gilts achieved a superior endometrial gland development (EGD) than white crossbred gilts during the ovary-independent period (before 60 d of age). Then, the EGD continues under the management of ovary-derived steroid hormones that regulated by gut microbiota (after 60 d of age). However, whether Meishan gilts’ superiority in EGD lasting to the ovary-dependent period (after 60 d of age) and the role of gut microbiota in this period both remain unclear. Meishan gilts and Landrace x Yorkshire (LxY) gilts were raised under the same housing and feeding conditions until sexual maturity and then we compared their EGD and gut microbiota. Meanwhile, we transplanted fecal microbiota from Meishan gilts to L×Y gilts to explore the role of gut microbiota in EGD. We sampled plasma every 3 weeks and collected the uterus, ovary, liver, and rectal feces after the sacrifice. We then determined the hormone concentrations and expressions of the EGD-related genes. We also profiled the gut microbiota using 16S rDNA sequencing and metabolites of plasma and liver tissue using untargeted metabolomics. Finally, the correlation analysis and significant test was conducted between FMT-shifted gut microbes and EGD-related indices. Meishan gilts have larger endometrial gland area (P < 0.001), longer uterine horn length (P < 0.01) but lighter uterine horn weight (P < 0.05), a distinctive gut microbiota compared with L×Y gilts. Fecal microbiota transplantation (FMT) increased endometrial gland area (P < 0.01). FMT markedly shifted the metabolite profiles of both liver and plasma, and these differential metabolites enriched in steroid hormone biosynthesis pathway. FMT increased estradiol and insulin-like growth factor 1 but decreased progesterone dynamically. FMT also increased the expression of the EGD-related genes estrogen receptor 1 gene, epithelial cadherin, and forkhead box protein A2. There is a significant correlation between FMT-shifted gut microbes and EGD-related indices. Sexually matured Meishan gilts achieved a superior EGD than LxY gilts. Meanwhile, gut microbiota contribute to the EGD potentially via regulating of steroid hormones during the ovary-dependent period.

中文翻译：

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肠道菌群在卵巢依赖时期促进小母猪子宫内膜腺的发育

在卵巢非依赖期（60 d龄之前），高产梅山小母猪的子宫内膜腺发育（EGD）优于白色杂交小母猪。然后，EGD继续在卵巢微生物类固醇调节的卵巢衍生类固醇激素的管理下（年龄在60天后）。然而，梅山后备母猪在EGD上的优势是否持续到卵巢依赖期（年龄在60 d后）以及肠道菌群在该时期的作用都尚不清楚。在相同的饲养和饲养条件下饲养眉山小母猪和长白×约克夏（LxY）小母猪直到性成熟，然后我们比较它们的EGD和肠道菌群。同时，我们将眉山小母猪的粪便菌群移植到L×Y小母猪上，以探讨肠道菌群在EGD中的作用。我们每3周采样一次血浆，收集子宫，卵巢，肝，粪便牺牲后和直肠。然后，我们确定了EGD相关基因的激素浓度和表达。我们还使用16S rDNA测序分析了肠道菌群，并使用了非靶向代谢组学分析了血浆和肝组织的代谢产物。最后，进行了FMT转移肠道微生物与EGD相关指标之间的相关性分析和显着性检验。梅山小母猪的子宫内膜腺体面积较大（P <0.001），子宫角长度较长（P <0.01），但子宫角重量较轻（P <0.05），与L×Y小母猪相比，肠道菌群独特。粪便微生物群移植（FMT）增加了子宫内膜腺体面积（P <0.01）。FMT明显改变了肝脏和血浆的代谢产物谱，这些差异代谢产物富含类固醇激素生物合成途径。FMT增加雌二醇和胰岛素样生长因子1，但孕酮动态减少。FMT还增加了EGD相关基因雌激素受体1基因，上皮钙粘蛋白和叉头盒蛋白A2的表达。FMT移位的肠道微生物与EGD相关指数之间存在显着相关性。性成熟的眉山小母猪的EGD优于LxY小母猪。同时，肠道菌群可能通过在卵巢依赖期调节类固醇激素来促进EGD。性成熟的眉山小母猪的EGD优于LxY小母猪。同时，肠道菌群可能通过在卵巢依赖期调节类固醇激素来促进EGD。性成熟的眉山小母猪的EGD优于LxY小母猪。同时，肠道菌群可能通过在卵巢依赖期调节类固醇激素来促进EGD。