Due to the lack of corn and soybean meal in animal feeding, rice bran meal (RBM) has been proposed as a beneficial substitute for these feedstocks’ ingredients. Its fermentation by using diverse microbes has been adopted as a beneficial technique. In this study, 18 five-month-old finishing pigs (castrated Duroc × Landrace × Large White) were assigned to three dietary groups with six replicates in each group, designated as the control (CON), unfermented RBM (RBM), and fermented RBM (FRBM) groups. RBM was fermented with a mixture of Lactobacillus johnsonii L63 and hydrolytic enzymes at 37 °C and pH 4.8 for 60 h. The results indicated that incorporating 30% fermented or unfermented rice bran meal into the diets of finishing pigs had no significant effect on growth performance. Regarding serum biochemical parameters, most indicators, including alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and triglycerides, showed no significant alterations. However, in both the unfermented and fermented rice bran meal groups, the concentrations of serum total protein, albumin, globulin, cholesterol, and blood urea nitrogen were significantly decreased (p < 0.05), whereas serum nitric oxide levels were significantly increased (p < 0.05). The FRBM group improved intestinal morphology and the digestibility of nutrients (crude protein, ether extract, crude fiber, and gross energy) by altering the mTORC1 pathway and upregulating the relative expression of amino acid and peptide transporter genes in the jejunum. However, the dry matter digestibility decreased compared to the CON group. The RBM group reduced nutrient digestibility, along with alterations in hepatic gene expression related to amino acid metabolism and transport. Therefore, fermented rice bran meal may offer a potential substitute feed ingredient for use in swine diets when conventional ingredients like corn and soybean meal are in short supply.

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.

Background: The valorization of sustainable feed ingredients such fermented de-oiled rice bran meal (FDRBM) is crucial; however, the molecular mechanisms driving its benefits remain unclear. This study addresses this gap by investigating FDRBM as a dietary substitute for maize in rabbits to determine its effects on meat quality and underlying gut–liver axis communication. Methods: In an eight-week trial, New Zealand White rabbits were assigned to a control diet or the basal diet with a 20% substitution of either unfermented de-oiled rice bran (UFDRBM) or FDRBM. Post-trial, the researchers analyzed carcass traits, meat quality, and nutritional composition. A multi-omics approach integrates gene expression data from the ileum and muscle with liver metabolomics to model coordinated biological responses. Results: Although growth performance was similar, the FDRBM diet significantly improved meat quality by enhancing water-holding capacity and increasing essential amino acids (p < 0.05). Mechanistically, these improvements were associated with the upregulation of genes associated with oxidative muscle fiber (Tnnc1) and lipid metabolism. Analysis of the gut–liver axis revealed that FDRBM enhanced ileum antioxidant capacity, which coincided with profound reprogramming of liver metabolism (p < 0.01 *), identifying C17-sphinganine as a differential metabolite. Conclusion: This study provides novel insights into the mode of action of FDRBM, suggesting that it enhances rabbit meat quality in part by modulating metabolic gene expression and is associated with coordinated molecular changes across the gut–liver axis.