Dietary 4-Hydroxy-2,5-Dimethyl-3(2H)-Furanone Supplementation in Hu Sheep: Implications on Fecal and Rumen Microbiota

This study aimed to investigate the effects of dietary 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) supplementation on ruminal and fecal microbial diversity, community composition, and predicted functional pathways. A total of 24 four-month-old female Hu sheep with similar body weights (20.6 ± 0.5 kg) were randomly allocated to two groups, with six replicates per group and two sheep per replicate. One group was fed a basal diet (CON), and the other received the same basal diet supplemented with 100 mg/kg HDMF. The results showed that ruminal microbial alpha diversity did not differ between the CON and HDMF groups (p > 0.05), whereas fecal microbial richness and evenness were higher in the CON group than in the HDMF group (p < 0.05). Beta diversity of ruminal microbiota did not differ between groups (R = 0.0667, p = 0.217), whereas fecal microbiota exhibited significant differences (R = 0.7333, p = 0.002). Dietary HDMF supplementation increased the relative abundances of Lachnospiraceae and Oribacterium in the rumen, elevated Spirochaetota and Lachnospiraceae AC2044 group in feces, and concurrently decreased Desulfobacterota and Alistipes in feces. Correspondingly, PICRUSt2-based functional prediction indicated putative associations between HDMF-induced microbial shifts and altered functional pathways, including increased relative abundances of amino acids biosynthesis and ABC transporter pathways, concomitant with decreased relative abundances of glycolysis/gluconeogenesis and pyruvate metabolism pathways in feces. These results suggest that dietary HDMF supplementation was associated with more pronounced alterations in fecal microbiota than in ruminal microbiota. This study provides a preliminary microbial ecology perspective on gastrointestinal microbiota in response to dietary HDMF supplementation in ruminants.