Epimedii Folium Supplementation Improves Semen Quality, Hormonal Profile, and Immune Function by Modulating Gut...

This study aimed to investigate the effects of dietary Herba Epimedii Folium (HEF) supplementation on semen quality, reproductive hormones, immune parameters, gut microbiota, and seminal plasma metabolites in aged boars, and to evaluate its potential for extending their reproductive lifespan. A total of 18 Bama boars (approximately 3 years of age) were randomly assigned to three groups (n = 6 per group). The control group received a basal diet, while the treatment groups were fed the basal diet supplemented with 3 g/kg or 5 g/kg of HEF for 8 weeks. The results showed that adding HEF to the diet of aged boars increased the motility and concentration of their sperm and reduced the proportion of abnormal sperm. Treatment with 3 g/kg HEF increased serum LH and IgG levels, whereas the 5 g/kg dose elevated IgA levels in both serum and seminal plasma, as well as IgG levels in seminal plasma. Furthermore, 16S rRNA sequencing revealed that dietary HEF supplementation reduced the relative abundance of Streptococcus and Oscillospiraceae UCG-002 in the gut of aged boars. PICRUSt2 analysis predicted that pathways involved in lysine biosynthesis, arginine and proline metabolism, glycine, serine and threonine metabolism, and amino acid-related enzymes were enriched in the HEF treatment group. Semen metabolite profiling showed that the HEF treatment enriched several key metabolites, including 5-hydroxytryptophan, acetylcarnitine, tretinoin, methyltestosterone, prostaglandin A3, and prostaglandin B2. Spearman correlation analysis revealed a negative association between Streptococcus abundance and sperm motility, whereas acetylcarnitine, 5-hydroxytryptophan, and prostaglandin A3 were positively associated with motility. Furthermore, 5-hydroxytryptophan levels were positively linked to both sperm concentration and serum LH. In summary, our study demonstrates that Epimedii Folium may enhance the semen quality of aged Bama boars by improving the intestinal microbiota and the metabolic profile of seminal plasma. These findings may offer a theoretical basis for optimizing reproduction and conserving germplasm resources in aged Bama miniature pigs.