Gut microbiota contributes to the development of endometrial glands in gilts during the ovary-dependent period

Background: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.Methods: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.Results: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.Conclusion: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.