Probiotics play an important role in animal production, providing health benefits to the host by improving intestinal microbial balance. In this study, we added three different probiotics, Saccharomyces cerevisiae (SC), Bacillus licheniformis (BL), and lactic acid bacteria (LAB), and compared them with the control group (CON), to investigate the effects of probiotic supplementation on growth performance, gut microbiology, and gut flora of S. trutta. Our results showed that feeding probiotics improved the survival, growth, development, and fattening of S. trutta. Additionally, probiotic treatment causes changes in the gut probiotic community, and the gut flora microorganisms that cause significant changes vary among the probiotic treatments. However, in all three groups, the abundance of Pseudomonas, Acinetobacter, and Rhizophagus bacterial genera was similar to that in the top three comparative controls. Furthermore, differences in the composition of intestinal microbiota among feed types were directly associated with significant changes in the metabolomic landscape, including lipids and lipid-like molecules, organic acids and derivatives, and organoheterocyclic compounds. The probiotic treatment altered the gut microbiome, gut metabolome, and growth performance of S. trutta. Using a multi-omics approach, we discovered that the addition of probiotics altered the composition of gut microbiota, potentially leading to modifications in gut function and host phenotype. Overall, our results highlight the importance of probiotics as a key factor in animal health and productivity, enabling us to better evaluate the functional potential of probiotics.

Supplementation of sodium butyrate (SB) has been proved to be beneficial for improving the growth performance and health of animals, but its effects on rabbits have not been well understood. Therefore, this study aimed to investigate the effects of SB supplementation on growth performance, meat quality, and intestinal health of rabbits by evaluating feed intake and efficiency, diarrhea index, blood and cecum metabolites, cecal pH and short‐chain fatty acids (SCFAs), histological staining, nutritional composition of meat, and gene expression profile of cecum. A total of 14 weaned male New Zealand White rabbits (35 ± 2 days, 1.70 ± 0.09 kg) were randomly divided into two groups: rabbits in Control group were fed normally with the basal diet, and rabbits in Butyrate group were supplemented with 0.75 g/kg SB on the basis of the basal diet. After a 1‐week acclimatization period, the formal trial lasted for 10 weeks. Results suggest that dietary SB reduced the feed conversion ratio and diarrhea index of rabbits ( p < 0.05). SB treatment significantly increased serum glutamyl transpeptidase, total bile acid, total cholesterol, triglyceride, and glucose levels and decreased tCO ₂ content relative to the Control group ( p < 0.05). Meanwhile, crude ash content in rabbits' meat was significantly increased by SB treatment ( p < 0.05). Furthermore, SB treatment significantly increased the integrity of epithelial villi and number of goblet cells in the cecum and decreased cecal pH compared with the Control group. Dietary SB also upregulated levels of Na ⁺ ‐K ⁺ ATPase, Ca ²⁺ ‐Mg ²⁺ ATPase, total superoxide dismutase, and glutathione peroxidase in cecum. SCFAs analysis revealed that dietary supplementation with SB increases butyric acid in the cecum contents. Furthermore, SB supplementation is demonstrated to stimulate the proliferation and migration of cecal epithelial cells through activating Wnt/β‐catenin pathways in rabbits both in vitro and in vivo by using transcriptome sequencing and gene function verification technologies. Taken together, our findings provide a theoretical basis for the application of SB as an alternative to antibiotics in livestock production.

Coprophagy prevention (CP) affects the growth performance, hepatic lipid synthesis, and gut microbiota in rabbits. Supplementation with Clostridium butyricum (C. butyricum, Strain number: CCTCC M 2019962) has been found to improve growth performance in rabbits. However, it remains unknown whether C. butyricum can ameliorate the effects of CP on hepatic lipid synthesis and the underlying mechanisms are yet to be elucidated. Therefore, this study aimed to investigate the impact of CP on hepatic lipid synthesis and the underlying mechanism based on the gut–liver axis. The findings revealed that supplementation with C. butyricum could reverse CP-related growth performance, lipid accumulation, bile acid synthesis, and inflammation. Furthermore, C. butyricum exerted protective effects on the gut by preserving intestinal barrier integrity and modulating gut microbiota composition; these factors may represent potential mechanisms through which C. butyricum improves CP-related outcomes. Specifically, C. butyricum reshaped the microbiota by increasing butyric acid levels, thereby maintaining secondary bile acid (deoxycholic acid, chenodeoxycholic acid) balance and attenuating the inhibitory effects of the FXR/SHP pathway on lipid synthesis (SREBP1c/ApoA1). Moreover, the activation of butyrate/GPR43pathway by C. butyricum reduced damage to the intestinal barrier (ZO-1/Occludin/Claudin1) and restored the gut immune microenvironment in CP rabbits. In summary, supplementation with C. butyricum can alleviate the adverse effects of CP on growth performance and hepatic lipid synthesis by modulating the gut–liver axis.