1000 g maize cob mixed material was synergistically fermented by adding 2.5% composite probiotics and 0.06‐0.08% NSP (nonstarch polysaccharide) enzyme to prepare fermented feed, and its effectiveness as feed for fattening pigs was investigated. The results showed that the appearance, texture, and nutrient quality of maize cobs significantly improved after fermentation, the total number of bacteria was 4.5 × 10¹⁰ CFU/g, and the protein content was 7.1%. Compared to the control group, the pigs in the 6% fermented maize cob feed experimental group showed significantly increased daily feed intake, daily weight gain, and nutrient digestion rate (p < 0.05) and reduced feed conversion ratio (p < 0.05). Most indicators including slaughter performance and meat quality significantly improved. In addition, beneficial bacteria including Lactobacillus in the intestines of the finishing pigs significantly increased, and pathogenic bacteria including Escherichia coli in the intestines and feces were found to be significantly reduced (p < 0.05). The intestinal crypt depth, VH/CD ratio, and ileal mucosal immunity of the finishing pigs also significantly improved (p < 0.05). The cytokine content and gene expression of sIgA, IL‐8, and TNF‐α were found to be significantly increased (p < 0.05). It could be concluded that the addition of 6% fermented maize cob feed to the diets of finishing pigs could promote their growth, improve their production performance and slaughter performance meat quality, and enhance their intestinal microecological balance and immunity.

To research the isolation, identification, physiological property of Clostridium butyricum strain using lactic acid from pig and its effects on intestinal function of weaned piglets, the C. butyricum strain LY33 was isolated with an anaerobic culture method from the intestinal contents of healthy piglets fed with lactic acid bacteria fermented feeds. The strain LY33, which was identified as Clostridium butyricum according to morphological, physiological, biochemical and 16S rRNA sequence analyses, was found to be efficient in lactic acid utilisation and butyric acid conversion. Strain LY33 was non-toxic and resistant to heat, gastric acid and bile salts. It utilised lactic acid efficiently when cultured in LADM liquid medium (Lactic acid decomposition medium) under the initial conditions of pH 5.5 and a lactic acid concentration of 132 mmol. Strain LY33 also had inhibitory effects on Escherichia coli, Salmonella, and other pathogens. Conversely, it promoted the growth of lactic acid bacteria. Compared to the control group fed the basal diet, the indexes of intestinal function of piglets in the experimental group fed the strain LY33 preparation improved markedly, and for most of these indicators, a difference at p < .05 was achieved.

The flora compositions of nitrogen‐fixing bacteria in roots of Pennisetum giganteum z.x.lin at different growth stages and the expression and copy number of nitrogen‐fixing gene nifH were studied by Illumina Miseq second‐generation sequencing technology and qRT‐PCR. The results showed that there were more than 40,000~50,000 effective sequences in 5 samples from the roots of P. giganteum, with Proteobacteria and Cyanobacteria as the dominant nitrogen‐fixing bacteria based on the OTU species annotations for each sample and Bradyrhizobium as the core bacterial genera. The relative expression and quantitative change of nifH gene in roots of P. giganteum at different growth stages were consistent with the changes in the flora compositions of nitrogen‐fixing microbia. Both revealed a changing trend with an initial increase and a sequential decrease, as well as changing order as jointing stage>maturation stage>tillering stage>seedling stage>dying stage. The relative expression and copy number of nifH gene were different in different growth stages, and the difference among groups basically reached a significant level (p < 0.05). The relative expression and copy number of nifH gene at the jointing stage were the highest, and the 2^-△△CT value was 4.43 folds higher than that at the seedling stage, with a copy number of 1.32 × 10⁷/g. While at the dying stage, it was the lowest, and the 2^-△△CT value was 0.67 folds, with a copy number of 0.31 × 10⁷/g.

Bacillus coagulans LYBC06 strain with lactate-producing capacity was isolated from mucosal tissue of the digestive tract of a fattening pig. The resequencing of the LYBC06 strain revealed that the overall genome was less variable, with a genome-wide heterozygous ratio of 0.042 %, total SNP locus variants 0.4273% of the entire genome, total InDel mutations 0.0182%, total increased and decreased CNV copies 0.0031% and total SV annotated variants 0.0083% of the entire genome. The mutated genes were mainly involved in the growth of the strain, regulation of energy metabolism, and production of proteases and lactate. The whole genome of LYBC06 strain was sequenced with the length of 3385106 bp, GC content of 46.86% and 4092 coding genes (85.96% of coding). Functional annotation of the proteins encoding genes showed that the growth process of LYBC06 strain involved several metabolic pathway transformation processes of various substances, and many encoding genes were involved in the resistance to macrolides, polypeptides and tetracyclines. The basic characteristics of the genome of LYBC06 strain were relatively similar to those of other Bacillus coagulans, and the collinearity between several Bacillus coagulans strains was relatively good. Bacterial growth, gene expression of lactate dehydrogenase and lactate production in LYBC06 strain were largely synchronized, and the maximum amount of lactate could be produced up to 92 g/L at 16 h culture during the logarithmic growth phase, in which the LdhL1 gene played an important role in the production of lactate in LYBC06 strain.

Objective: To analyze the chemical composition of tea tree oil (TTO) and elucidate the antibacterial mechanisms of its major component, terpinen-4-ol (T-4-O), against Staphylococcus aureus . Methods: The chemical constituents of TTO were determined using GC MS. The antibacterial mechanism of T-4-O was investigated from multiple perspectives, including its in vitro antibacterial activity, effects on bacterial growth, morphology, cell membrane and cell wall integrity, as well as leakage of cell lysates and proteins, cell cycle progression, and transcriptional responses. Results: GC-MS analysis revealed that TTO contained 15 compounds, primarily alcohols, alkenes, alkanes, and esters, among which T-4-O was the most abundant component, accounting for 31.09%. T-4-O exhibited strong antibacterial activity against S. aureus , with a minimum inhibitory concentration (MIC) of 2.12 mg/mL and a minimum bactericidal concentration (MBC) of 8.47 mg/mL. At 2 × MIC, T-4-O effectively suppressed bacterial growth. Furthermore, T-4-O disrupted metabolic pathways associated with biofilm formation, leading to approximately 50% inhibition of S. aureus biofilm development. It also induced structural disorganization of the cell membrane and impaired cell wall synthesis, resulting in leakage of cellular lysates, proteins, and other intracellular components. As a consequence, normal cell division and growth were inhibited, and the bacterial cell cycle was arrested at the R phase. Ultimately, these cumulative effects caused cell membrane rupture and bacterial death. Conclusion: T-4-O exerts significant antibacterial effects against S. aureus primarily by disrupting cell membrane integrity, inhibiting biofilm formation, and inducing cell cycle arrest, collectively leading to bacterial death.