Integrated Multi-Omics Analysis Reveals that Rumen Fluid Transplantation Reprograms Duodenal Function and Promotes Subcutaneous Fat Deposition in Xizang Sheep
To systematically evaluate the effects of rumen fluid transplantation (RFT) on small intestinal function and fat deposition in ruminants, this study used Tibetan sheep as a model and employed a comprehensive approach including histological analysis, transcriptome sequencing, targeted and non-targeted metabolomics, and 16S rRNA microbial sequencing to perform multi-level analysis of duodenal structure, metabolic regulation, microbiota composition, and subcutaneous fat phenotype. Results showed that RFT significantly promoted subcutaneous fat cell hypertrophy and lipid droplet deposition, and simultaneously improved duodenal tissue structure, manifested as increased villus height and width, deepened crypts, and increased goblet cell number. Transcriptome analysis revealed significant upregulation of genes related to energy metabolism and tissue remodeling, including PMCH, HAMP, and MMP9. Metabolome results showed that differentially metabolites were mainly enriched in glycerophospholipid metabolism and the ABC transport pathway, with increased levels of fatty acids (myristic acid, palmitoleic acid, and arachidonic acid) and a directed adjustment in bile acid composition (decreased GUCA and TLCA, and increased UDCA/TUDCA). Microbial analysis revealed that the Ruminococcus_gauvreauii_group is associated with steroid and inflammatory lipid metabolism, while the Lachnospiraceae_NK3A20_group is primarily associated with fatty acid and glycerophospholipid metabolism. In summary, rumen fluid transplantation enhances duodenal absorptive function through multi-level synergistic regulation, thereby promoting host fat deposition.