Search Results (130)

To screen high-quality porcine-derived lactic acid bacteria for swine production, this study compared growth performance, acid production, acid and bile salt tolerance, and genome characteristics of Lactobacillus plantarum (MRS002), Lactobacillus amylovorus (MRS003), and Lactobacillus salivarius (MRS004). All experiments were performed with three biological replicates, and data were analyzed using the GraphPad Prism software 8.4.3 by one-way analysis of variance (one-way ANOVA) followed by Tukey’s multiple comparison test (significance level p < 0.05). All three strains showed typical anaerobic growth. L. amylovorus MRS003 had a longer growth cycle and higher biomass, while L. plantarum MRS002 and L. salivarius MRS004 grew faster and produced more acid, with pH values reaching 4.2 and 4.3 at 24 h, respectively. L. plantarum MRS002 and L. salivarius MRS004 also exhibited higher survival rates under 0.3% bile salt and pH 2.0 stress. Genome annotation revealed that more than 50% of genes were related to metabolism in all strains. L. plantarum MRS002 possessed the most comprehensive metabolic and stress-resistance gene networks; L. amylovorus MRS003 shows genomic enrichment in starch-degradation pathways and appears promising for high-starch feed fermentation; and L. salivarius MRS004 showed unique advantages in aromatic amino acid metabolism (e.g., phenylalanine, tyrosine, and tryptophan biosynthesis). In summary, based on the evaluated in vitro indicators, L. salivarius MRS004 has more favorable phenotypic characteristics, L. plantarum MRS002 has broad adaptability, and L. amylovorus MRS003 is suitable for high-starch feed fermentation. This study provides a theoretical basis for the research and development of probiotic products. Full article

The development of sustainable alternatives to fossil-based feedstocks is a global priority in light of climate change and resource depletion. Seaweeds, particularly green seaweeds, represent promising candidates for biorefinery applications due to their rapid growth, high carbohydrate content, and non-competition with arable land. In this study, the feasibility of lactic acid production from acid hydrolysates of the green seaweed Ulva pertusa was systematically investigated. Proximate composition analysis revealed that dried Ulva pertusa contained 52.3% carbohydrates, highlighting its suitability as a fermentation substrate. Acid hydrolysis with dilute sulfuric acid released 23.8 g of fermentable monosaccharides per 100 g of biomass, with L-rhamnose and D-glucose as the predominant sugars. Fermentation experiments were conducted using five Lactobacillus strains (L. casei, L. plantarum, L. brevis, L. salivarius, and L. rhamnosus). Among these, L. rhamnosus and L. salivarius achieved the highest lactic acid yields (0.66 g g⁻¹), followed by L. plantarum (0.63 g g⁻¹), whereas L. casei and L. brevis exhibited comparatively lower yields (0.46 and 0.39 g g⁻¹, respectively). Time-course analysis demonstrated that the superior strains reached maximum productivity within 9 h, significantly faster than typical lignocellulosic feedstocks such as corn stover, which require extensive pretreatment and longer fermentation times. Furthermore, the mineral-rich composition of Ulva pertusa (notably Mg²⁺ and Ca²⁺) provided intrinsic nutrients that supported microbial growth, thereby reducing the requirement for external supplementation. Comparative evaluation with lignocellulosic hydrolysates confirmed that Ulva pertusa offers higher efficiency, faster kinetics, and lower process complexity. To our knowledge, this work represents the first comprehensive assessment of multiple Lactobacillus strains for lactic acid production from Ulva pertusa hydrolysates. The findings highlight the unique advantages of green seaweeds as a sustainable biomass resource and contribute to the advancement of marine biomass-based biorefineries. Future studies should focus on improving the utilization of non-fermentable sugars, optimizing fermentation strategies, and evaluating techno-economic feasibility on an industrial scale. Full article

This study aims to investigate the effects of low-energy diets (LE) supplemented with Lactobacillus reuteri postbiotics (HSY) on growth performance and intestinal health of broiler chickens. A total of 2400 one-day-old Ross 308 broiler chicks with an average initial body weight of 46.10 ± 0.04 g were randomly assigned to a 2 × 2 factorial arrangement of treatments with 12 pens and 50 broiler chickens/pen for 39 days. Treatments were (1) CTR (basal diet), (2) LE (CTR-70 kcal ME/kg), (3) HSY (CTR + 0.5 kg/t HSY), and (4) LEHSY (LE + 0.5 kg/t HSY). LE increased the feed conversion ratio (FCR) of broilers (p = 0.03) without altering ADG, ADFI, and final BW. Supplementation with HSY significantly reduced the FCR of broilers (p = 0.001). HSY upregulated the activities of amylase and trypsin in jejunal digesta (p < 0.01). Furthermore, LE upregulated the expression of intestinal barrier-related genes such as Mucin-2, Claudin-1 and Occludin, and HSY upregulated the expression of Claudin-1 (p < 0.05). LE upregulated the expression of nutrient transport carriers such as SGLT1 and TRPV6 (p < 0.01), and HSY upregulated the expression of TRPV6 (p < 0.01). LE upregulated the expression of immune-related genes such as MHC-II (p = 0.002), and HSY upregulated the expression of IFN-γ, IL-10, and TGF-β (p < 0.05). LE and HSY both downregulated the expression of intestinal lipid metabolism-related genes like ACC, while upregulating the expression of FABP4 (p < 0.05). 16S rRNA sequencing showed that the HSY increased the Chao1 index of the jejunal microbiota and enriched beneficial bacteria such as Lactobacillus salivarius and Lactobacillus avium. LE and HSY both increased the concentrations of propionic and butyrate (p < 0.05). In summary, HSY can improve gut health and mitigate the negative impact of low-energy treatment on broiler growth performance by increasing the content of endogenous enzymes in the jejunum, improving gut microbiota structure, and increasing the content of short-chain fatty acids in the jejunum. Full article

The industrial application of starter cultures requires stable physiological and genetic performance. In this study, Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus were continuously subcultured. Physiological stability was assessed through colony morphology, fermentation activity, and growth profiling. Genetic stability was evaluated through comparative genomics of carbohydrate metabolism networks and single-nucleotide polymorphism (SNP) analysis. The results showed that after 2000 generations, the cellular morphology of the strains remained intact. Additionally, the strains exhibited enhanced growth performance and fermentation capability. The Gompertz model revealed that adapted S. thermophilus A37 and L. bulgaricus B29 exhibited shortened lag phases, increased maximum specific growth rates, and high stationary-phase cell densities. Phenotypic microarray and comparative genomics revealed that S. thermophilus mainly used mono- and disaccharides, with impaired ribose metabolism due to the absence of the rbsk gene in the pentose phosphate pathway. In contrast, L. bulgaricus metabolized diverse oligosaccharides, sugar alcohols, and plant-derived substrates. Additionally, it effectively catabolized ribose through the phosphoketolase pathway and possessed a trehalose degradation cluster. All strains exhibited genomic stability, with SNPs revealing fewer than 21 variations per isolate. This study provides an important theoretical foundation for evaluating the stability of fermentation starter cultures. Full article

This study investigates the effects of N-acetylneuraminic acid (Neu5Ac) on intestinal microbial composition and metabolic activity in piglets using two complementary approaches: in vitro fermentation and in vivo dietary supplementation with coated Neu5Ac. In vitro fermentation results demonstrated that Neu5Ac stimulates higher production of formate and acetate by piglet intestinal microbiota compared with other human milk-derived monosaccharides (p < 0.05). In vivo feeding trials showed that dietary coated Neu5Ac significantly increased microbial α-diversity and altered the overall microbial composition in both the jejunum and colon (p < 0.05). For instance, coated Neu5Ac reduced the relative abundances of ASV1 Clostridium and ASV17 Clostridium in the jejunum, while raising the relative abundances of ASV3 Veillonella, ASV4 Veillonella, ASV7 Lactobacillus salivarius, ASV11 Actinobacillus porcitonsillarum in the jejunum, and ASV41 Xylanibacter in the colon (p < 0.05). Furthermore, coated Neu5Ac significantly elevated formate and acetate concentrations in the jejunum (p < 0.05) and exhibited a trend toward increased acetate levels in the colon (0.05 < p < 0.1). Collectively, using piglets as a model, this study demonstrates that Neu5Ac facilitates the intestinal colonization of beneficial microbes (e.g., Lactobacillus), leading to enhanced production of microbial metabolites, particularly formate and acetate, which may contribute to improved gut homeostasis in early life. Full article

Drawing on two indigenous chicken breeds that have adapted for centuries to the hyper-arid Tarim Basin, namely the Baicheng You Chicken and Hotan Black Chicken, this study provides a high-resolution map of their gut microbiota across the duodenum, jejunum, ileum and cecum and subsequently isolates putative probiotic strains from cecal contents using conventional culture techniques. In the duodenum, Lactobacillus dominated Hotan Black Chicken (43.16%), whereas Ligilactobacillus prevailed in Baicheng You Chicken (37.03%). This segregation persisted in the jejunum, with Lactobacillus accounting for 62.55% of Hotan Black Chicken reads and Ligilactobacillus accounting for 60.76% reads in Baicheng You Chicken. The ileal core of Hotan Black Chicken remained Lactobacillus (50.63%), while Baicheng You Chicken shifted to Enterococcus (32.37%). In the cecum, both breeds converged on the Rikenellaceae RC9 gut group as the single dominant lineage (Hotan Black Chicken, 46.87%; Baicheng You Chicken, 46.23%). At the genus level, Hotan Black Chicken was enriched in Lactobacillus and Ligilactobacillus, whereas Baicheng You Chicken harbored a greater proportion of Enterococcus. Concurrently, eight strains with in vitro probiotic attributes were isolated, four from each breed, identified as Ligilactobacillus salivarius, Limosilactobacillus reuteri, Lactobacillus gallinarum, Enterococcus lactis, Enterococcus faecium, Enterococcus faecalis, and Bacillus velezensis. This study deciphers the intestinal microbiome of two native Tarim Basin chicken breeds, Hotan Black Chicken and Baicheng You Chicken, and mines them for autochthonous probiotic strains. The obtained dataset has established a foundational resource for poultry-related probiotics adapted to extremely arid environments, providing theoretical insights and practical value for poultry nutritionists in water-scarce regions in the future. Full article

As the critical component of the gastrointestinal tract, which lives in trillions of gut microorganisms, in a healthy state, the host interacts with the gut microbiota and is symbiotic. The species Limosilactobacillus reuteri, Ligilactobacillus salivarius, and Lactobacillus johnsonii are indigenous gut commensal bacteria that are mainly found in the digestive tracts. These three bacteria possess a variety of characteristics that reflect their ability to adapt to the gastrointestinal environment. Herein, we summarize the current progress of research on the probiotic properties of these strains in terms of their ability to protect against harmful pathogens, maintain intestinal health, and improve disease outcomes. These bacteria can impact the intestinal barrier function and enhance intestinal immunity through various mechanisms, such as upregulating the tight-junction protein expression and mucin secretion of intestinal epithelial cells, adjusting and balancing the gut microbiota, and blocking pro-inflammatory cytokine production. They have been shown to ameliorate intestinal inflammation in animal models and provide protective effects against various healthy issues in humans, including diarrhea, constipation, colorectal cancer, obesity, and liver diseases. However, the detailed mechanisms of certain strains remain unclear. Full article

UVB radiation induces cutaneous damage through oxidative stress and immune dysregulation. This study investigated the therapeutic potential of Gastrodia elata fermented by Lactobacillus salivarius AACE1 (GL) in a mouse model of UVB-induced skin injury. Results demonstrated that GL treatment significantly improved skin morphology, enhanced antioxidant activities (SOD and GSH), reduced oxidative damage (MDA), and balanced inflammatory mediators by upregulating TGF-β and IL-10 while downregulating TNF-α, IL-6, and IL-1β. Transcriptomic analysis revealed that GL specifically activated NOD-like receptor signaling pathway components (Nlrp3, Casp4, and Gbp2/5) while inducing Tnfaip3 to establish negative feedback control. Metabolomic profiling confirmed that fermentation transformed the metabolite landscape, enriching collagen-related dipeptides, antimicrobial/anti-inflammatory metabolites, and antioxidant cofactors. Importantly, comparative analysis showed that GL is more effective than vitamin E in coordinating multiple signaling pathways and maintaining inflammatory homeostasis. These findings establish GL as an effective natural product that alleviates UVB-induced skin damage through synchronized metabolic remodeling and controlled immune activation. Full article

Allergic rhinitis (AR) is a common heterogeneous chronic disease characterized by high prevalence, complex pathogenesis, and susceptibility to multiple contributing factors. Currently, its prevalence ranges from 20% to 30% in adults and reaches up to 40% in children. Extensive research has confirmed significant differences in nasal microbiota composition between AR patients and healthy individuals, most notably alterations in the abundance of four dominant phyla: Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Among these, the most striking abundance alterations occur in Staphylococcus aureus and Streptococcus salivarius within the nasal mucosa of AR patients, suggesting a critical role of nasal microbiota in AR initiation and progression. In response, researchers have proposed microbiome-targeted therapeutic strategies. For example, nasal local administration of probiotics (e.g., Lactobacillus and Bifidobacterium) aims to reshape the nasal microbiota. Additionally, protective bacteria such as Corynebacterium accolens and Dolosigranulum pigrum can inhibit pathogenic bacteria, thereby correcting microbial dysbiosis and alleviating AR symptoms. This review summarizes the composition of the nasal microbiota, the latest research progress on its association with AR, and the underlying potential mechanisms. It provides novel insights and potential therapeutic strategies for the prevention and treatment of AR. Full article

This study characterized the rumen microbiota of Duolang sheep, a Xinjiang local breed, to identify potential probiotics for Hu sheep. 16S rRNA sequencing revealed that Duolang sheep possessed a distinct rumen microbial structure (beta-diversity, p < 0.05), lower diversity (higher Simpson index, p < 0.01), and a higher Firmicutes-to-Bacteroidetes ratio compared to Hu sheep. Subsequently, a Duolang-derived strain, Ligilactobacillus salivarius (L. salivarius) KS1018, was evaluated in a 56-day feeding trial with Hu sheep. Supplementation enhanced systemic immunity (serum IgG and IgM) and antioxidant status (SOD) (p < 0.05). Metabolic profiles were also modified, with serum β-hydroxybutyrate (BHB) level increasing significantly in both medium-dose (p < 0.001) and high-dose (p < 0.05) groups, whereas BUN and lipid markers (TG, CHOL) elevated significantly in the medium-dose (p < 0.05) and high-dose group (p < 0.05), respectively. The strain with medium- and high-dose also reduced fecal crude fat (p < 0.01) and influenced mucosal secretory immunoglobulin A (sIgA) by increasing levels in the duodenum while decreasing them in the rumen (p < 0.05). Ruminal histology was also altered (p < 0.01). Spearman’s correlation analysis showed that Prevotellaceae_UCG-003 was positively correlated with serum BUN (p < 0.001), IgM (p < 0.05), BHB (p < 0.01), and SOD (p < 0.01). Overall, L. salivarius KS1018 improved antioxidant capacity, systemic and mucosal immunity, and ruminal structure in Hu sheep, demonstrating its potential to influence host–microbe interactions in livestock. Full article

The cage-free rearing of laying hens combined with probiotics promotes intestinal health. The aim of this study was to evaluate the effect of adding probiotics on the intestinal microbiota of Isa Brown laying hens raised in a cage-free system. A total of 450 Isa Brown hens, 19 weeks old, were used in a cage-free system over three 28-day cycles in a completely randomized design with five treatments and six replicates, containing 15 birds per pen. The Isa Brown hens were fed a basal ration based on corn and soybean meal; a basal ration plus a single strain of Bacillus subtilis (500 g/t); a basal ration plus a single strain, Bacillus subtilis (1000 g/t); a basal ration plus a probiotic blend (Bacillus subtilis, Enterococcus faecium, Lactobacillus acidophilus, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactobacillus reuteri, Lactobacillus salivarius, Pediococcus acidilactici) at a dosage of 200 g/t; and a basal ration plus the blend at 400 g/t. From one hen per replicate, contents from the small intestine, including the duodenum, jejunum, and ileum, were collected for DNA extraction and bacterial species identification. There was an increase in Helicobacter brantae, which was quantified at 86% in the diet containing 1000 g/t of the probiotic single strain of Bacillus subtilis and 87% in the diet containing 500 g/t dosage, in comparison to the basal ration. With the probiotic blend at 200 g/t, 37% Lactobacillus crispatus and 21% Lactobacillus aviarius were observed, while the dosage of 400 g/t of the probiotic blend increased the level of Lactobacillus kitasatonis to 68% compared to the basal ration. The inclusion of 200 g/t of the probiotic blend proved to be more beneficial to the small intestinal microbiota of laying hens. Full article

This study aimed to evaluate the combined effects of two probiotic strains, Lactobacillus salivarius TRM58163 and Lactobacillus johnsonii TRM59525—originally isolated from human infant feces (aged 0–6 months)—on growth performance, antioxidant capacity, liver function, intestinal morphology, and cecal microbiota in 100-day-old Baicheng You chickens fed a low-protein diet. Ten strains isolated from infant feces were initially screened, and eight were assessed in vitro for safety, gastrointestinal tolerance, and antimicrobial activity. TRM58163 and TRM59525 showed the best probiotic potential. A total of 240 Baicheng You chickens (100 days old) were randomly assigned to two groups: The control group was fed a low-protein diet (CLD), while the experimental group had Lactobacillus salivarius TRM58163 and Lactobacillus johnsoni TRM59525 added to the low-protein diet (LLD, ≥1 × 10⁹ CFU/g feed). Each treatment included four replicates of 30 chickens over 42 days. Probiotic supplementation significantly improved average daily feed intake (ADFI), average daily gain (ADG), and feed conversion ratio (FCR) (p < 0.05). It also enhanced antioxidant status, with increased plasma superoxide dismutase activity and reduced malondialdehyde levels. Lower total bilirubin levels indicated improved liver function. The LLD group showed increased ileal villus height and villus-to-crypt ratio. 16S rRNA gene sequencing revealed greater microbial diversity, increased beneficial genera (e.g., Akkermansia, Bacteroides), and decreased harmful taxa (e.g., Sutterella). These microbial shifts were associated with improved growth and metabolic profiles. In conclusion, L. salivarius TRM58163 and L. johnsonii TRM59525 supplementation improved performance, gut health, and microbial composition, supporting their use as functional probiotics in low-protein poultry diets. Full article

To discover new probiotics that can protect mammary glands from mastitis, 40 Lactobacillus (Ligilactobacillus) spp. isolates from bovine milk were subjected to a preliminary series of in vitro subtractive analyses. Antibiotic susceptibility testing was performed according to the ISO norm 10932. Many lactobacilli had elevated MIC values for kanamycin (35%), but fewer were resistant to chloramphenicol (15%), streptomycin (7.5%) and tetracycline (5%). The enzymic activities of lactobacilli were tested using an API ZYM system. Nearly 27% exhibited undesirable activities (β-glucuronidase, β-glucosidase and N-acetyl-β-glucosaminidase). The safe strains were monitored for antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, and Bacillus cereus using microtiter plates and for their ability to form biofilms using the crystal violet assay. The antimicrobial activity of lactobacilli against indicator bacteria ranged from 29 to 89% and the isolates exhibited moderate-to-high biofilm formation. Suitable strains were selected for whole-genome sequencing analysis. Antibiotic-resistance genes and putative virulence genes were not predicted in the genomic analysis. Moreover, the isolate Ligilactobacillus salivarius 48 carries genetic information responsible for bacteriocin production that is similar to that encoding salivaricin CRL1328. Our study demonstrates the safety of the above mentioned isolate, which has potential to be used as a probiotic, exerting health benefits through production of antimicrobial substances. Full article

This study evaluated the safety, antimicrobial activity, and upper gastrointestinal gastroprotection of a postbiotic powder derived from Lactobacillus salivarius AP-32, Lactobacillus paracasei ET-66, and Lactobacillus plantarum LPL28. Safety assessments were performed in rodent models through acute and subchronic oral toxicity tests, genotoxicity assays, and biogenic amine analysis. No signs of toxicity were observed in either the acute (20 g/kg body weight, BW) or subchronic (3 g/kg BW) toxicity tests. Genotoxicity evaluations indicated no mutagenic activity in the Ames test (≤5000 µg/plate) and no chromosomal or micronuclear abnormalities in the spermatocyte or the peripheral blood assays (≤10 g/kg BW). Biogenic amines were undetectable in the postbiotic powder, further reinforcing its safety. The postbiotic powder showed significant direct antimicrobial activity. Additionally, it enhanced the inhibitory effects of probiotics against key upper gastrointestinal pathobionts including Streptococcus mutans, Porphyromonas gingivalis, Fusobacterium nucleatum subsp. polymorphum, and Actinobacillus actinomycetemcomitans, Helicobacter pylori. Moreover, the postbiotic powder demonstrated gastroprotective effects by promoting recovery in a hydrogen peroxide-induced gastric injury model. Based on these findings, the postbiotic powder is safe, non-toxic, and suitable for oral consumption at the tested doses, with promising antimicrobial and gastroprotective potential. Future research should explore its potential applications in health promotion and food safety. Full article

In piglets, the gut microbiota matures in a segment-specific manner during the nursing period, while fecal-based studies provide limited functional resolution across intestinal sites. We profiled the ileum using 16s rRNA gene sequencing and assessed segmental functions by shotgun metagenomics at selected ages. Ileal species richness and diversity were relatively stable across days. Lactobacillus were prominent from day 7, with stage-associated taxa including Lactobacillus johnsonii, Lactobacillus delbrueckii, Ligilactobacillus salivarius, and Limosilactobacillus pontis. Through metagenomic functional analysis, at 21 days, genes were enriched in butanoate metabolism, and Limosilactobacillus pontis as a potential probiotic played an important role in it. At day 28, metagenomic analysis indicated higher relative abundance in the ileum of pathways linked to cysteine and methionine metabolism and lysine biosynthesis, largely carried by Limosilactobacillus mucosae, Limosilactobacillus oris, and Limosilactobacillus pontis. These data describe the composition and function of the ileum in the intestines of piglets and indicate a differentiation period around day 21 to day 28. Full article