High-fiber diet alters fecal microbiota and enhances fiber utilization and short-chain fatty acid production in tibetan pigs

Abstract Background This study investigated the responses of growth performance, apparent nutrient digestibility, serum biochemical indices, fecal enzyme activity, short-chain fatty acids (SCFA), and fecal microbiota to a high-fiber diet in Tibetan pigs by manipulating dietary neutral detergent fiber (NDF) levels. Forty healthy Tibetan pigs with an initial body weight (IBW) of (13.46 ± 1.34) kg were randomly assigned to two groups: a control group (CON, NDF 8.80%) and a high-fiber group (HF, NDF 14.94%), with 20 replicates each and one pig per replicate. The experiment consisted of a 7-d adaptation period followed by a 28-d feeding trial. Results Different dietary NDF levels had no significant effects on growth performance between the CON and HF groups. The digested amount of crude fiber (CF) was significantly increased in the HF group ( P < 0.05). The HF group showed a significantly reduced apparent digestibility of acid detergent fiber ( P < 0.05), while no significant differences were observed in the digestibility of other nutrients. Fecal cellulase activity was significantly higher in the HF group than in the CON group ( P < 0.05). In addition, the concentrations of acetate, propionate, and butyrate in feces were significantly increased in the HF group ( P < 0.05). The relative abundances of Coprococcus and p-75-a5 were also significantly elevated ( P < 0.05). Spearman correlation analysis revealed that Coprococcus abundance was positively correlated with isobutyrate levels, and p-75-a5 was positively correlated with cellulase activity ( P < 0.05). Conclusion A high-fiber diet did not compromise growth performance in post-weaning Tibetan piglets and was associated with higher fecal cellulase activity, increased fecal acetate, propionate, and butyrate concentrations, and changes in selected bacterial taxa. These findings may provide useful reference information for the application of high-fiber diets in Tibetan pig production.