Bacillus subtilis has been widely used in animal husbandry as a potential alternative to antibiotics due to its excellent bacteriostasis and antioxidant activity. This study aims to investigate the effects of Bacillus subtilis on the protection of ducks from Escherichia coli infection and its mechanism. The four experimental groups include the negative control group, positive control group, antibiotic group and Bacillus subtilis group. Ducks in positive, antibiotic and Bacillus subtilis groups are orally administered with Escherichia coli and equivalent saline solution for the negative group. The results show that supplements with Bacillus subtilis enhances the performance and health status of the infected ducks. Moreover, Bacillus subtilis alleviates the increase in globulin, LPS and MDA, and the decrease in albumin, T-AOC and T-SOD in the serum caused by Escherichia coli infection. Bacillus subtilis also attenuates injury in the intestine and partially reverses the increase in ROS production and the depletion of ATP in the jejunum. These effects are accompanied with the change of related genes of the ribosome (13.54%) and oxidative phosphorylation (6.68%). Collectively, Bacillus subtilis alleviates the damage caused by Escherichia coli infection in ducks by activating ribosome and oxidative phosphorylation signaling to regulate antioxidant and energy metabolism.

Peanut meal (PNM) is a byproduct of the peanut oil extraction process, but its application is seriously limited by the presence of anti-nutritional factors, imbalance in amino acid profiles, and susceptibility to mycotoxin contamination. This study was conducted to investigate the effects of solid-state fermentation on the nutritional quality of PNM, as well as the effects of PNM and fermented peanut meal (FPNM) on the ileal digestibility of amino acids and apparent metabolizable energy (AME) of broiler chickens. The results indicated that the fermentation improved the quality of PNM by increasing the crude protein, TCA-soluble protein, and L-lactic acid concentration (p < 0.05), and decreasing the crude fiber, phytic acid, and aflatoxin B₁ concentration (p < 0.05). Solid-state fermentation also increased the free amino acids level and improved the balance of hydrolyzed amino acids of PNM. A nitrogen-free diet was used to determine the loss of endogenous amino acid in birds, and the PNM or FPNM as the only protein source to formulate semi-purified diets. The result showed that feeding on FPNM resulted in higher apparent ileal digestibility (AID) and standardized ileal digestibility (SID) values of the essential amino acids of methionine, lysine, leucine, and phenylalanine (p < 0.05). Moreover, the AID and SID values of the non-essential amino acids of FPNM were both higher than those of PNM, except for proline (p < 0.05). The AME was determined by the classic substitution method, and the results showed that fermentation had no effect on the AME value (p > 0.05). In conclusion, solid-state fermentation improved the nutritional value of PNM, and FPNM was a potential ingredient as an alternative protein source for broilers.

Inorganic polyphosphate (PolyP) is a high-molecular-weight polymer that plays multiple roles in regulating immune responses. However, the specific anti-inflammatory mechanisms of bacteria-derived PolyP are unclear. In the present study, PolyP was extracted from Lactobacillus plantarum (L. plantarum), and the chain length was estimated to be approximately 250 Pi residues. The immune regulatory functions of PolyP were investigated using a lipopolysaccharide (LPS)-induced RAW264.7 cell oxidative stress model, and dexamethasone was used as a positive control. The result revealed that both dexamethasone and PolyP were protective against oxidative stress by inhibiting macrophage M1 polarization and the production of several markers, such as nitric oxide (NO), reactive oxygen species (ROS), inducible nitric oxide synthase (iNOS), and cyclooxygenase (COX)-2. In addition, PolyP suppressed inflammation progression by regulating the production of several cytokines, such as interleukin (IL)-1β, interferon (INF)-γ, tumor necrosis factor (TNF)-α, and IL-6, and inhibited the expressions of inhibitory κB kinase (IKK) α, IKKβ, and extracellular regulated protein kinases 2 (ERK2). Conclusively, PolyP derived from L. plantarum has the ability to protect cells from oxidative stress damage by inhibiting M1 polarization in macrophages. These findings provide insights into the function of PolyP and offer support for the potential application of PolyP in immune-related diseases.

Zanthoxylum bungeanum seed meal (ZBM), a novel plant protein raw material, has shown promising potential in enhancing the growth of broiler chickens as a substitute for soybean meal (SBM) in feed. In the artificial digestive experiment of vitro experiments, the digestibility of ZBM and SBM were assessed using the SDS-III Single Stomach Animal Biometric Digestion System. Subsequently, 180 1-day old AA chicks were divided into three groups for in vivo experiments: corn–soybean-meal-based diet (CON group); ZBM replacing 5% soybean meal in the basal diet (ZBM-1 group); ZBM replacing 10% soybean meal in the basal diet (ZBM-2 group). The experiment period lasted for 42 days. Compared to SBM, ZBM demonstrated higher crude protein content, dry matter digestibility, and extracorporeal digestible protein. Compared with the CON group, the broilers in the ZBM-2 group showed improved ADG and ADFI during the 1–21 d, 22–42 d, and 1–42 d periods (p < 0.05). Furthermore, the ZBM groups exhibited significant increases in slaughter performance compared with the CON group (p < 0.05). The substitution of ZBM for SBM also leads to a significant reduction in serum enzyme indicators (p < 0.05). Additionally, the lipoprotein and total cholesterol of the ZBM groups were significantly lower than those of the CON group (p < 0.05). Substituting SBM with ZBM significantly enhances the activity of superoxide dismutase and the content of immunoglobulin G in broiler serum, while reducing the content of malondildehyde (p < 0.05). The ZBM groups showed significantly higher utilization of dry matter, crude protein, and energy compared with the CON group (p < 0.05). In conclusion, the study confirmed that the substitution of SBM with 5–10% ZBM in broiler diets has a significant positive effect on growth, development, antioxidant capacity, immune function, and nutrient utilization. This study not only provides a theoretical foundation for the utilization of ZBM in broiler diets but also offers an effective approach for reducing reliance on soybean meal.

Two experiments were conducted to test the hypothesis that the apparent metabolizable energy (AME) and standardized ileal digestibility (SID) of amino acids (AA) in fermented soybean meal (FSBM) are greater than those in soybean meal (SBM). FSBM was produced by fermenting SBM with a mixture of Bacillus amyloliquefaciens, Lactobacillus acidophilus, and Saccharomyces cerevisiae. The fermentation process decreased trypsin inhibitor and crude fiber levels by 67.80% and 7.56%, while it increased the total amino acid content by 2.56%. In the first experiment, a substitution method was used to determine the AME and nitrogen-corrected AME (AMEn) of SBM and FSBM. A corn-SBM basal diet and two test diets consisting of 70% of the basal diet plus 30% SBM or FSBM were formulated. The results show that fermentation did not have an effect on the AME and AMEn concentrations of SBM (p > 0.05); the respective AME and AMEn values were 10.29 and 10.62 MJ/kg (DM basis) and 9.09 and 9.23 MJ/kg for SBM and FSBM. In the second experiment, a nitrogen-free diet was formulated to measure the endogenous AA flow, and the other two semi-purified diets containing SBM or FSBM as the sole source of AA were formulated. The results show that the AID and SID of isoleucine, leucine, phenylalanine, valine, cysteine, tyrosine, and aspartic acid were greater in FSBM than in SBM (p < 0.05). In conclusion, the fermentation of SBM by a mixture of B. amyloliquefaciens, L. acidophilus, and S. cerevisiae can improve its nutritional values and is a promising protein resource for broiler production.

This study evaluated changes in nutritional components and antinutritional factors in rapeseed meal before and after microbial fermentation. It further investigated the enhancements in its nutritional value and the growth-promoting effects of fermented rapeseed meal on broiler chickens. A total of 180 one-day-old male Arbor Acres (AA) broilers were randomly allocated into 3 treatment groups, with 6 replicates per group and 10 birds per replicate. The broilers were fed a basal diet (CON), a diet with 5% soybean meal (SBM) replaced by RSM (RSM-5), or a diet with 5% SBM replaced by FRSM (FRSM-5). The date of the experiment was 28 June 2025. The results showed that FRSM improves protein quality and reduces the levels of antinutritional factors, including glucosinolates (GSL), phytic acid (PA), and condensed tannins (CT), compared with unfermented RSM. Additionally, FRSM enhances antioxidant capacity in vitro, significantly enhancing the scavenging rates of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, hydroxyl radicals (•OH), and superoxide anion radicals (O₂•⁻). In the broiler feeding trial, the FRSM-5 group had significantly higher average daily gain (ADG) during the periods of 22–42 d and 1–42 d (p < 0.05), along with a significantly lower feed to gain ratio (F/G) (p < 0.05), compared with the CON and RSM-5 groups. Compared to the CON group, the FRSM-5 group showed a significantly higher slaughter rate (SR), full eviscerated rate (FER), and breast muscle rate (BMR) (p < 0.05), whereas the RSM-5 group had significantly lower SR and FER (p < 0.05). The activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC) in the serum and liver of the FRSM-5 group were significantly higher than those in the CON and RSM-5 groups (p < 0.05), and the serum immunoglobulin (IgA, IgG, and IgM) levels were significantly elevated (p < 0.05). Furthermore, compared with the CON and RSM-5 groups, the FRSM-5 group exhibited a significant increase in duodenal villus height (VH) (p < 0.05), a significant reduction in duodenal crypt depth (CD) (p < 0.05), and a consequent significant increase in the VH/CD (p < 0.05). In conclusion, microbial fermentation effectively enhances the nutritional value of RSM by improving its nutrient composition and reducing antinutritional factors. Replacing 5% SBM with FRSM in broiler diets significantly improves growth performance, enhances antioxidant capacity and immune function, and optimizes intestinal morphological structure, thereby replacing part of the soybean meal in broiler diets.