Isolation and Evaluation of Probiotic Potential of Lactic Acid Strains From Healthy Equines for Potential Use in Salmonella Infection

Analysis of the antioxidant properties of Lactiplantibacillus plantarum EA3 isolated from fermented yak milk based on whole genome sequencing

Lactiplantibacillus plantarum EA3 was isolated from traditional fermented yak milk in the Gannan Tibetan Autonomous Prefecture of Gansu Province, China. Whole-genome analysis revealed that the EA3 genome is 3.47 Mb in size, consisting of a circular chromosome and three plasmids. The circular chromosome measures 3,318,230 bp in length with a GC content of 44.48 %. Functional annotation identified at least ten regulatory pathways and 33 protein-coding genes associated with oxidative stress, whose abundance correlates with free radical scavenging rates and oxygen tolerance. Additionally, genes encoding ten acid-tolerant proteins, ten bile salt-tolerant proteins, 26 adhesive proteins, and 12 bacteriocin-related proteins were detected. In vitro experiments have confirmed that EA3 can withstand up to 4 mM H2O2. Both the cell suspension and fermentation supernatant of EA3 exhibited significant radical scavenging activity and reducing power, highlighting its robust antioxidant properties. EA3 demonstrated high survival rates under harsh conditions, including pH 2.5 (90.24 %) and 1.2 % bile salt, and displayed antibacterial activity against Salmonella and Staphylococcus aureus. The EA3 genome lacked virulence factors, and its sensitivity to antibiotics, absence of hemolytic activity, and inability to produce biogenic amines confirmed its safety. These findings suggest that Lactiplantibacillus plantarum EA3 possesses exceptional antioxidant properties, making it a promising candidate for functional food production.

The Therapeutic Effects of Lactic Acid Bacteria Isolated from Spotted Hyena on Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic condition characterized by recurrent episodes and an unclear etiology. Given the limitations of current therapeutic options, which include suboptimal efficacy and significant side effects, there is a pressing need to explore novel treatments. Probiotics derived from diverse species have been identified as a promising approach for managing IBD, owing to their anti-inflammatory properties and their ability to regulate gut flora, among other beneficial effects.

METHODS

In this study, three strains of lactic acid bacteria (LAB) were isolated from the feces of the scavenger spotted hyena (Crocuta crocuta), a scavenging mammal. Based on their capability to survive within and adhere to the gastrointestinal tract, along with their profile of antibiotic resistance, a high-quality strain of Lactobacillus acidophilus (LA) was selected and demonstrated to be safe for mice. Subsequently, the therapeutic efficacy of LA was evaluated using a dextran sulfate sodium (DSS)-induced model of ulcerative colitis in mice.

RESULTS

The results indicated that LA restored the disease activity index and improved histopathological lesions in the model group. It also reduced inflammation and oxidative stress and significantly restored the expression of mucins and intestinal tight junction (TJ) proteins (ZO-1, Occludin). Furthermore, LA corrected the DSS-induced disruption of the intestinal flora, leading to a significant decrease in the prevalence of potentially harmful bacterial genera, such as Bacteroides, and an increase in beneficial bacterial genera, including Lactobacillus. In conclusion, Lactobacillus acidophilus LA1, isolated from spotted hyena feces, has potential as a functional supplement for alleviating symptoms of IBD and regulating intestinal flora.

Isolation, identification and characteristics of Bibersteinia trehalosi from goat

A conditionally pathogenic bacterium called Bibersteinia trehalosi inhabits the upper respiratory tract of ruminants and is becoming a significant cause of pneumonia, especially in goats. In this study, we identified a gram-negative bacteria strain isolated from dead goat's lungs, which was named M01. By integrating the outcomes of its morphological and biochemical characterization with the investigation of the 16S rRNA gene sequence analysis, the isolate was identified as B. trehalosi. Based on antibiotic susceptibility tests, the isolate was shown to be resistant to β-lactams, tetracyclines, and amphenicols. Its genome was discovered to comprise 2115 encoded genes and a circular chromosome measuring 2,345,568 bp using whole genome sequencing. Annotation of the VFBD database revealed that isolate M01 had four virulence genes encoding three virulence factors. The CARD database revealed that its genome has two antibiotic-resistance genes. Based on pathogenicity testing, isolate M01 was highly pathogenic to mice, primarily causing pneumonia, with an LD50 of 1.31 × 107 CFU/ml. Moreover, histopathology showed loss of alveolar structure and infiltration of lung inflammatory cells. Hence, the current study could provide sufficient information for prevention and control strategies for future epidemics of B. trehalosi in goat species.

Bioprotective potential of lactic acid bacteria for Salmonella biocontrol in vitro

Lactic acid bacteria (LAB) are an important option for Salmonella control in animal production, resulting in lower antibiotic use. The objective of this research was to isolate LAB from meat products and from commercial probiotics sold as nutritional supplements for in vitro verification of their bioprotective potential. Eleven bacteria were identified as Pediococcus acidilactici, two as Lacticaseibacillus rhamnosus, one as Lacticaseibacillus paracasei paracasei, one as Limosilactobacillus fermentum, and one as a consortium of Lactobacillus delbrueckii bulgaricus and L. fermentum. All bacteria showed inhibitory activity against Salmonella, with emphasis on the inhibition of P. acidilactici PUCPR 011 against Salmonella Enteritidis 33SUSUP, S. Enteritidis 9SUSP, S. Enteritidis 56301, S. Enteritidis CRIFS 1016, Salmonella Typhimurium ATCC™ 14,028®, and Salmonella Gallinarum AL 1138, with inhibition halos of 7.3 ± 0.5 mm, 7.7 ± 1.0 mm, 9.0 ± 1.8 mm, 7.3 ± 0.5 mm, 7.7 ± 1.0 mm, and 7.3 ± 0.5, respectively. The isolates P. acidilactici PUCPR 011, P. acidilactici PUCPR 012, P. acidilactici PUCPR 014, L. fermentum PUCPR 005, L. paracasei paracasei PUCPR 013, and L. rhamnosus PUCPR 010 showed inhibition greater than 2 mm against at least 3 Salmonella and were used for encapsulation and in vitro digestion. The encapsulation efficiency ranged from 76.89 ± 1.54 to 116.48 ± 2.23%, and the population after 12 months of storage was from 5.31 ± 0.17 to 9.46 ± 0.09 log CFU/g. When simulating swine and chicken digestion, there was a large reduction in bacterial viability, stabilizing at concentrations close to 2.5 log CFU/mL after the analyses. The analyzed bacteria showed strong in vitro bioprotective potential; further analyses are required to determine in vivo effectiveness.

Effects of different grains on bacterial diversity and enzyme activity associated with digestion of starch in the foal stomach

Background

Compared with the stomach of ruminant cattle, the stomach of horse is small and mainly for chemical digestion, but the microorganisms in the stomach play an important role in maintaining the homeostasis of the internal environment. Due to the complexity of the microbes in the stomach, little is known about the diversity and structure of bacteria in the equine stomach. Grains are the main energy source for plant-eating livestock and energy is derived through enzymatic hydrolysis of grains into glucose or their microbial fermentation into Volatile fatty acids (VFA). However, the mechanism through which these ingested grains are chemically digested as well as the effect of these grains on the stomach remains elusive. This study explored the effects of feeding different grains (corn, oats, and barley) on bacterial diversity, structure, and composition in the foal’s stomach content. Furthermore, the effects of different grains on the vitality of starch digestion-related stomach enzymes were investigated.

Results

No significant differences were observed (P > 0.05) in the bacterial rarefaction curves of Operational Taxonomic Units (OTUs) and diversity of the stomach microbiota in all foals. This study also revealed the statistical differences for Firmicutes, Cyanobacteria, Actinobacteria, Fibrobacteres, Lactobacillaceae, Streptococcaceae, Unidentified_Clostridiales, Prevotellaceae, Lactobacillus, Streptococcus, Unidentified_Cyanobacteria, Unidentified_Clostridiales, Lactococcus, Sphingomonas, Lactobacillus_hayakitensis, Lactobacillus_equigenerosi, and Clostridium_perfringens. The linear discriminant analysis effect size analysis revealed 9 bacteria at each classification level. The functional analysis of species information by using FAPROTAX software was able to predict 35 functions, and the top 5 functions were chemoheterotrophy, fermentation, animal_parasites_or_symbionts, nitrate_reduction, and aerobic_chemoheterotrophy. The study also revealed statistical differences for pH, glucose concentration, β-amylase, maltase, and amylase.

Conclusions

The different grains had no significant effect on the microbial diversity of the stomach content of the foal. However, the relative bacterial abundances differed significantly in response to different diets. Particularly, oats fed to the foals significantly increased the relative abundance of Firmicutes, Lactobacillaceae, Lactobacillus, and Lactobacillus_hayakitensis. The grain had no significant effect on the pH of the stomach content, glucose concentration, and enzyme viability in the foal.

Effects of Lactic Acid Bacteria Isolated from Equine on Salmonella-Infected Gut Mouse Model

The aim of this study was to evaluate the antibacterial potential of lactic acid bacteria (Weissella confuse, Pediococcus acidilactici, and Ligilactobacillus equi) isolated from healthy equine in Wuhan against Salmonella Typhimurium CVCC542-induced mice model on intestinal microflora. In previous studies, these isolated strains showed good probiotic potentials in vitro. In this study, fifty healthy mice were randomly divided into five groups, the blank control group, the control group, the Pediococcus acidilactici group (1 × 10⁸ CFU/day), the Ligilactobacillus equi group (1 × 10⁸ CFU/day), and the Weissella confuse group (1 × 10⁸ CFU/day). The body weight in control group and Weissella confuse group showed significant decreased (P < 0.05, P < 0.01), while Pediococcus acidilactici group and Ligilactobacillus equi group showed good recovering after treatments. The lowest diarrhea rate was shown in Ligilactobacillus equi group after treatment. In histopathology, Ligilactobacillus equi group showed the least structural damage in duodenum, and all probiotic treatment groups showed less damage in cecum. The sequence data and optical transform unit showed that Pediococcus acidilactici group and Ligilactobacillus equi group had higher number than control group, while the diversity data showed that the control group and Weissella confuse group had lower diversity in cecum. Microbial community analysis showed increased abundance of Firmicutes, Bacteroidetes, uncultured_bacterium_f_Muribaculaceae, and Lactobacillus in treatment groups, while potential microbes that can induce intestinal diseases such as Verrucomicrobia, Akkermansia, and Lachnospiraceae_NK4A136_group decreased in the treatment groups. In conclusion, lactic acid bacteria isolated from the healthy horses could alleviate the infection of Salmonella and regulate intestinal flora.

Probiotic potential of Lactobacillus isolated from horses and its therapeutic effect on DSS-induced colitis in mice

Inflammatory bowel disease (IBD) is a refractory disease that endangers both humans and animals. In recent times, Lactobacillus have been used to treat animal diseases. It may be a good choice to try to isolate Lactobacillus with probiotic potential to treat IBD. Equine, as a kind of hindgut fermentation animal has rich intestinal microflora, but data regarding this is scarce. The isolation of Lactobacillus with probiotic potential from equine may become a new method for the treatment of IBD. Four isolates of Lactobacillus were isolated from fresh feces of healthy male adult horses and analyzed their biological characteristics. According to the phylogenetic analysis, A2.5 and A7.1 were identified as Pediococcus pentosaceus, A3 as Lactobacillus plantarum, and B8.2 as Weissella cibaria. All four isolates showed tolerance to the environment of acid, bile salt concentration and simulated artificial gastrointestinal fluid. The hydrophobic rate and self-aggregation rate of A3 were close to 100%, and the adhesion rate was 28.85 ± 0.74%. Four isolates were negative in hemolysis test and sensitive to common antibiotics and different isolates had different sensitivity to antibiotics. The four isolates had antibacterial and antioxidant activities which can reflect their probiotic potential. Furthermore, they could regulate the LPS (Lipopolysaccharides) stimulated Caco-2 cells. We chose A3 as the treatment strain to intervene Dextran sulfate sodium salt (DSS)-induced mice. The results showed that compared with DSS group, DSS + A3 group exhibited reduced Disease activity index (DAI), increased colon length, reduced pathological score and regulated cytokine secretion at the level of gene expression. In this study, four isolates of Lactobacillus with probiotic potential were isolated, and Lactobacillus plantarum A3 with reduced ulcerative colitis in mice was screened. It might provide a potential treatment for IBD.

Production of Organic Acid and Short-Chain Fatty Acids (SCFA) from Lactic Acid Bacteria Isolate on Oligosaccharide Media

The growth of microorganisms in food, one of which is lactic acid bacteria (LAB), can produce metabolites beneficial to health. It is essential to study the results of LAB metabolism to improve the quality of a functional food product. This study aimed to evaluate the isolates Lactobacillus acidophilus FNCC 0051 and Lactobacillus rhamnosus R23 to metabolize oligosaccharides as a carbon source so that the final fermentation product can benefit health especially in lowering cholesterol. In vitro testing was carried out on MRS media with or without oligosaccharides, either singly or in a combination consisting of galactooligosaccharides (GOS), fructooligosaccharides (FOS), inulin (IN), inulin hydrolyzate (HI), or their combination as prebiotics by adding 0.3 % oxbile (bile salt) and inoculated with 1% v/v LAB isolate culture and incubated at 37°C for 24 hours. The results showed that the main product of oligosaccharide metabolism by L. acidophilus FNCC 0051 and L. rhamnosus R23 produced several organic acids (lactic acid), including short-chain fatty acids (SCFA) (acetic acid, propionic acid, and butyric acid). The single and combined carbon sources affected the proportion of lactic acid and acetic acid produced by L. acidophilus FNCC0051 (p<0.05). However, they did not affect the proportions of propionic acid and butyric acid. While in L. rhamnosus R23 (p<0.05), the presence of a single carbon source significantly affected the proportions of lactic acid, acetic acid, propionic acid, and butyric acid, while the combination of oligosaccharides affected the proportions of lactic acid and butyric acid produced. SCFA is the main product of prebiotic metabolism, but the characteristics of the acid produced have not been identified. The fermentation pattern is thought to be related to molecular weight, chain length, and oligosaccharide structure. Short-chain molecules, such as FOS generally ferment more rapidly than long-chain molecules such as inulin. The results of this study indicate that both isolates can be used as probiotics in the development of symbiotic products with the addition of oligosaccharides, which have a physiological effect in lowering cholesterol levels.