Incorporation of unfermented or fermented de-oiled rice bran meal into a rabbit's diet impacts growth performance, nutrient digestibility, cecal microbiota composition, and intestinal barrier function.

Objective: This study assessed the effects of incorporating unfermented or fermented rice bran meal (RBM) into a rabbit's diet on their growth performance, cecal microbiota, and intestinal health.

Methods: Twenty-one male weaned New Zealand White rabbits aged 6 weeks were randomly allocated into 3 groups (n = 7). Rabbits consumed the basal diet in the control (CON) group and the basal diet with a 20% substitution of either unfermented RBM (UFRBM) or fermented RBM (FRBM) for 8 weeks. A combination of Lactobacillus johnsonii L63 with hydrolytic enzymes ([cellulase (100 U/g], phytase [1.25 U/g], and papain [300 U/g]) was used to FRBM for 60 h at 37°C and a pH value of 4.8.

Results: Our results demonstrated that the rabbits' growth performance, serum biochemical variables, and cecal microbiota for α and β diversities at the phylum level didn't differ among the treatments. The nutrient digestibility, cecal and jejunal morphology, or α-amylase and trypsin activities increased in the FRBM group than the CON and UFRBM groups, while the catalase and malondialdehyde activities decreased in the UFRBM group (p<0.05). The solute carrier families 15 and 5 levels were higher in the FRBM group than the UFRBM and CON groups, while the UFRBM group improved the levels of the solute carrier family 1, occludin, and V9D2013 group at the genus level than the FRBM and CON groups (p<0.05). The abundance of glycolysis-to-gluconeogenesis was increased in the FRBM and UFRBM groups compared to the CON group (p<0.05). The total short-chain fatty acid, acetate, and butyrate concentrations were, respectively, improved in the FRBM group than the CON and UFRBM groups (p<0.05).

Conclusion: The two formulas incorporating 20% of UFRBM or FRBM in rabbit diet should be recommended to farmers, particularly the FRBM, to decrease the reliance on corn and soybean meal for rabbit production.