Probiotic Features of Lactic Acid Bacteria Isolated from a Diverse Pool of Traditional Greek Dairy Products Regarding Specific Strain-Host Interactions

Immunomodulatory Activity on Human Macrophages by Cell-Free Supernatants to Explore the Probiotic and Postbiotic Potential of Lactiplantibacillus plantarum Strains of Plant Origin

Upon dietary administration, probiotic microorganisms can reach as live cells the human gut, where they interact with the microbiota and host cells, thereby exerting a beneficial impact on host functions, mainly through immune-modulatory activities. Recently, attention has been drawn by postbiotics, i.e. non-viable probiotic microbes, including their metabolic products, which possess biological activities that benefit the host. Lactiplantibacillus plantarum is a bacterial species that comprises recognised probiotic strains. In this study, we investigated in vitro the probiotic (and postbiotic) potential of seven L. plantarum strains, including five newly isolated from plant-related niches. The strains were shown to possess some basic probiotic attributes, including tolerance to the gastrointestinal environment, adhesion to the intestinal epithelium and safety. Besides, their cell-free culture supernatants modulated cytokine patterns in human macrophages in vitro, promoting TNF-α gene transcription and secretion, while attenuating the transcriptional activation and secretion of both TNF-α and IL-8 in response to a pro-inflammatory signal, and enhancing the production of IL-10. Some strains induced a high IL-10/IL-12 ratio that may correlate to an anti-inflammatory capacity in vivo. Overall, the investigated strains are good probiotic candidates, whose postbiotic fraction exhibits immunomodulatory properties that need further in vivo studies. The main novelty of this work consists in the polyphasic characterisation of candidate beneficial L. plantarum strains obtained from relatively atypical plant-associated niches, by an approach that explores both probiotic and postbiotic potentials, in particular studying the effect of microbial culture-conditioned media on cytokine pattern, analysed at both transcriptional and secretion level in human macrophages.

Heat-Killed Lactilactobacillus sakei WB2305 and Lactiplantibacillus plantarum WB2324 Inhibited LPS-Induced Inflammation in Human Airway Epithelial Cells

Asthma is characterized by inflammation of the airways, including the inflammatory and airway structural cells. Probiotics, which have diverse effects, even within the same species, are being studied to prevent and mitigate the severity of asthma. Lactilactobacillus sakei WB2305 and Lactiplantibacillus plantarum WB2324 were isolated from kimchi. These strains have acceptable probiotic properties and are safe. In addition, the anti-inflammatory potential of the heat-killed isolates against lipopolysaccharide (LPS)-induced inflammation in the human pulmonary epithelial cell line (A549) was investigated. The heat-killed Lact. sakei WB2305 and Lact. plantarum WB2324 reduced the chemokine and cytokines mRNA expression levels, as shown by the results of using real-time polymerase chain reaction. Western blotting results showed that the nuclear factor-kappa B (NF-κB) activation and mitogen-activated protein kinases (MAPK) signaling pathways were suppressed by treatment with the heat-killed strains. The production amounts of eotaxin, tumor necrosis factor-ɑ (TNF-α), and interleukin-6 (IL-6) were lower than those in LPS-only treated cells. Additionally, 2',7'-dichlorofluorescein diacetate (DCFH-DA) staining confirmed decreased reactive oxygen species (ROS) production in A549 cells. Therefore, the results of present study demonstrate the anti-inflammatory and anti-asthmatic activities of heat-killed Lact. sakei WB2305 and Lact. plantarum WB2324 in human airway epithelial cells.

Study of the Microbiome of the Cretan Sour Cream Staka Using Amplicon Sequencing and Shotgun Metagenomics and Isolation of Novel Strains with an Important Antimicrobial Potential

Staka is a traditional Greek sour cream made mostly from spontaneously fermented sheep milk or a mixture of sheep and goat milk. At the industrial scale, cream separators and starter cultures may also be used. Staka is sometimes cooked with flour to absorb most of the fat. In this study, we employed culture-based techniques, amplicon sequencing, and shotgun metagenomics to analyze the Staka microbiome for the first time. The samples were dominated by Lactococcus or Leuconostoc spp. Most other bacteria were lactic acid bacteria (LAB) from the Streptococcus and Enterococcus genera or Gram-negative bacteria from the Buttiauxella, Pseudomonas, Enterobacter, Escherichia-Shigella, and Hafnia genera. Debaryomyces, Kluyveromyces, or Alternaria were the most prevalent genera in the samples, followed by other yeasts and molds like Saccharomyces, Penicillium, Aspergillus, Stemphylium, Coniospotium, or Cladosporium spp. Shotgun metagenomics allowed the species-level identification of Lactococcus lactis, Lactococcus raffinolactis, Streptococcus thermophilus, Streptococcus gallolyticus, Escherichia coli, Hafnia alvei, Streptococcus parauberis, and Enterococcus durans. Binning of assembled shotgun reads followed by recruitment plot analysis of single reads could determine near-complete metagenome assembled genomes (MAGs). Culture-dependent and culture-independent analyses were in overall agreement with some distinct differences. For example, lactococci could not be isolated, presumably because they had entered a viable but not culturable (VBNC) state or because they were dead. Finally, several LAB, Hafnia paralvei, and Pseudomonas spp. isolates exhibited antimicrobial activities against oral or other pathogenic streptococci, and certain spoilage and pathogenic bacteria establishing their potential role in food bio-protection or new biomedical applications. Our study may pave the way for additional studies concerning artisanal sour creams to better understand the factors affecting their production and the quality.

Identification of safe putative probiotics from various food products

The objective of this study was to isolate, identify, and assess the safety and functionality in vitro of putative probiotic bacterial strains. Isolation procedures were based on standard methods using elective and selective media. The isolates were identified by comparative 16S rRNA sequencing analysis while their safety was determined according to the safety tests recommended by the FAO/WHO such as antibiotic resistance, hemolysin, and biogenic amine production. Most of the isolates did not pass the in vitro safety tests; therefore, only Lactiplantibacillus plantarum (from ant intestine and cheese), Lacticaseibacillus paracasei (from goat milk and kimchi), Enterococcus faecium (from chili doenjang and vegetables with kimchi ingredients), Limosilactobacillus fermentum (from saliva), and Companilactobacillus alimentarius (from kimchi) were identified and selected for further studies. The isolates were further differentiated by rep-PCR and identified to the strain level by genotypic (16S rRNA) and phenotypic (Gen III) approaches. Subsequently, the strain tolerance to acid and bile was evaluated resulting in good viability after simulated gastrointestinal tract passage. Adhesion to mucin in vitro and the presence of mub, mapA, and ef-tu genes confirmed the adhesive potential of the strains and the results of features associated with adhesion such as hydrophobicity and zeta potential extended the insights. This study reflects the importance of fermented and non-fermented food products as a promising source of lactic acid bacteria with potential probiotic properties. Additionally, it aims to highlight the challenges associated with the selection of safe strains, which often fail in the in vitro tests, thus hindering the possibilities of "uncovering" novel and safe probiotic strains.

Milk and Its Derivatives as Sources of Components and Microorganisms with Health-Promoting Properties: Probiotics and Bioactive Peptides

Milk is a source of many valuable nutrients, including minerals, vitamins and proteins, with an important role in adult health. Milk and dairy products naturally containing or with added probiotics have healthy functional food properties. Indeed, probiotic microorganisms, which beneficially affect the host by improving the intestinal microbial balance, are recognized to affect the immune response and other important biological functions. In addition to macronutrients and micronutrients, biologically active peptides (BPAs) have been identified within the amino acid sequences of native milk proteins; hydrolytic reactions, such as those catalyzed by digestive enzymes, result in their release. BPAs directly influence numerous biological pathways evoking behavioral, gastrointestinal, hormonal, immunological, neurological, and nutritional responses. The addition of BPAs to food products or application in drug development could improve consumer health and provide therapeutic strategies for the treatment or prevention of diseases. Herein, we review the scientific literature on probiotics, BPAs in milk and dairy products, with special attention to milk from minor species (buffalo, sheep, camel, yak, donkey, etc.); safety assessment will be also taken into consideration. Finally, recent advances in foodomics to unveil the probiotic role in human health and discover novel active peptide sequences will also be provided.

Acetolactate Decarboxylase as an Important Regulator of Intracellular Acidification, Morphological Features, and Antagonism Properties in the Probiotic Lactobacillus reuteri

SCORE

This study identifies the coding gene (aldB) of acetolactate decarboxylase (ALDC) as an important regulatory gene of the intracellular pH in Lactobacillus reuteri (L. reuteri), uncovering the important role of ALDC in regulating intracellular pH, morphological features, and antagonism properties in the probiotic organism L. reuteri.

METHODS AND RESULTS

The aldB mutant (ΔaldB) of L. reuteri is established using the homologous recombination method. Compare to the wild-type (WT) strain, the ΔaldB strain shows a smaller body size, grows more slowly, and contains more acid in the cell cytoplasm. The survival rate of the ΔaldB strain is much lower in low pH and simulated gastric fluid (SGF) than that of the WT strain, but higher in simulated intestinal fluid (SIF). The antagonism test demonstrates the ΔaldB strain can inhibit Listeria monocytogenes (L. monocytogenes) and Salmonella more effectively than the WT strain. Additionally, there is a dramatic decrease in the adhesion rate of Salmonella to Caco-2 and HT-29 cells in the presence of the ΔaldB strain compared to the WT strain. Simultaneously analyze, the auto-aggregation, co-aggregation, cell surface hydrophobicity (CSH), hemolytic, temperature, NaCl, oxidative stress, and antibiotic susceptibility of the ΔaldB strain are consistent with the features of probiotics.

CONCLUSION

This study highlights that the aldB gene plays a significant role in the growth and antibacterial properties of L. reuteri.

Probiotic characterization of Bacillus species strains isolated from an artisanal fermented milk product Dahi

Dahi, an artisanal fermented milk product, widely consumed in Pakistan, is microbiologically diverse, and many bacterial communities await investigation. The current study is first to present probiotic assessment of Bacillus species strains isolated from dahi. Based on 49 identified strains assessed, only 6 strains, i.e., Bacillus licheniformis QAUBL19, QAUBL1901, and QAUBL1902; Bacillus mycoides QAUBM19 and QAUBM1901; and Bacillus subtilis QAUBSS1 were having prominent persistence in the simulated gastrointestinal fluids, being non-hemolytic, with no DNase activity. Probiotic characteristics, cholesterol-assimilating, and carbohydrate-fermenting capabilities were assessed for all the strains. These six strains each showed variant cholesterol assimilating abilities. B. licheniformis QAUBL19 retaining most desired probiotic traits presented both notable cholesterol assimilating and bile salt hydrolase activities. It can be used as a probiotic of choice with hypocholesterolemia ability. B. subtilis QAUBSS1 showed wide carbohydrate fermentation ability and strongest antibacterial potential. It is likely to be considered a probiotic for living beings and starter culture for fermentation of food/feed.

Pilot-Scale Production of Traditional Galotyri PDO Cheese from Boiled Ewes’ Milk Fermented with the Aid of Greek Indigenous Lactococcus lactis subsp. cremoris Starter and Lactiplantibacillus plantarum Adjunct Strains

The performance of a mixed thermophilic and mesophilic starter culture consisting of Streptococcus thermophilus ST1 and the Greek indigenous nisin-A-producing Lactococcus lactis subsp. cremoris M78 was evaluated in the absence (A: ST1+M78) or presence (B: ST1+M78+H25) of Lactiplantibacillus plantarum H25—another indigenous ripening strain—under real cheesemaking conditions. Three pilot-scale trials of fresh (6-day-old) Galotyri PDO cheese were made from boiled milk by an artisanal method using simple equipment, followed by cold ripening of the A1–A3 and B1–B3 cheeses at 4 °C for 30 days. All of the cheeses were analyzed microbiologically and for pH, gross composition, proteolysis, sugar and organic acid contents, and sensorial attributes before and after ripening. The artisanal (PDO) Galotyri manufacturing method did not ensure optimal growth of the ST1+M78 starter as regards the constant ability of the thermophilic strain ST1 to act as the primary milk acidifier under ambient (20–30 °C) fermentation conditions. Consequently, major trial-dependent microbial and biochemical differences between the Acheeses, and generally extended to the Bcheeses, were found. However, high-quality Galotyri was produced when either starter strain predominated in the fresh cheeses; only trial A1 had microbiological and sensory defects due to an outgrowth of post-thermal Gram-negative bacterial contaminants in the acidified curd. The H25 adjunct strain, which grew above 7 to 9 log CFU/g depending on the trial, had minor effects on the cheese’s pH, gross composition, and proteolysis, but it improved the texture, flavor, and the bacteriological quality of the Bcheeses during processing, and it exerted antifungal effects in the ripened cheeses.

Probiotics and Postbiotics as the Functional Food Components Affecting the Immune Response

The food market is one of the most innovative segments of the world economy. Recently, among consumers there is a forming trend of a healthier lifestyle and interest in functional foods. Products with positive health properties are a good source of nutrients for consumers' nutritional needs and reduce the risk of metabolic diseases such as diabetes, atherosclerosis, or obesity. They also seem to boost the immune system. One of the types of functional food is "probiotic products", which contain viable microorganisms with beneficial health properties. However, due to some technical difficulties in their development and marketing, a new alternative has started to be sought. Many scientific studies also point to the possibility of positive effects on human health, the so-called "postbiotics", the characteristic metabolites of the microbiome. Both immunobiotics and post-immunobiotics are the food components that affect the immune response in two ways: as inhibition (suppressing allergies and inflammation) or as an enhancement (providing host defenses against infection). This work's aim was to conduct a literature review of the possibilities of using probiotics and postbiotics as the functional food components affecting the immune response, with an emphasis on the most recently published works.

In silico, in vitro and in vivo characterization of host-associated Latilactobacillus curvatus strains for potential probiotic applications in farmed Atlantic salmon (Salmo salar)

Salmon aquaculture is the fastest growing animal protein production system in the world; however, intensive farming leads to poor weight gain, stress, and disease outbreaks. Probiotics offer the potential to enhance growth performance and feed efficiency in Atlantic salmon, as well as immunostimulate fish against common pathogens, benefitting farmers and consumers with more efficient production. Here, we isolated and identified 900 native microbial isolates including 18 Lactobacilli from the farmed salmon intestines. Based on whole-genome sequencing and phylogenetic analysis, the Lactobacillus candidates belonged to Latilactobacillus curvatus (L. curvatus) species and formed two distinct phylogenetic groups. Using bioinformatics and in vitro analyses, we selected two candidates L. curvatus ATCC PTA-127116 and L. curvatus ATCC PTA-127117, which showed desirable safety and probiotic properties. The two L. curvatus candidates were evaluated for safety and efficacy (higher final weight) in Atlantic salmon alongside spore-forming Bacilli isolated from salmon, poultry, and swine. All the tested candidates were safe to salmon with no adverse effects. While we did not see efficacy in any Bacillus supplemented groups, compared to untreated group, the group administered with the two L. curvatus strains consortium in feed for seven weeks in freshwater showed indicators of improvement in final body weight by 4.2%. Similarly, the two L. curvatus candidates were also evaluated for safety and efficacy in Atlantic salmon in saltwater; the group administered with the two L. curvatus strains consortium in feed for 11 weeks showed indicators of improvement in final body weight by 4.7%. Comprehensive metabolomics analyses in the presence of different prebiotics and/or additives identified galactooligosaccharide as a potential prebiotic to enhance the efficacy of two L. curvatus candidates. All together, these data provide comprehensive genomic, phenotypic and metabolomic evidence of safety and desirable probiotic properties as well as indicators of in vivo efficacy of two novel endogenous L. curvatus candidates for potential probiotic applications in Atlantic salmon. The in vivo findings need to be confirmed in larger performance studies, including field trials.

Microbiological Characterization of Greek Galotyri Cheese PDO Products Relative to Whether They Are Marketed Fresh or Ripened

Galotyri is the most popular traditional Greek PDO soft acid-curd cheese. This study compared the microbial numbers and types and characterized the lactic acid bacteria (LAB) biota of two artisan-type Galotyri PDO cheese varieties, one marketed fresh (Brand-K) and the other ripened (Brand-Z). Two retail batches of each cheese variety were analyzed, and a total of 102 LAB isolates were biochemically identified. LAB (7.2–9.3 log CFU/g) prevailed in all cheeses, followed by yeasts (5.8–6.8 log CFU/g). Typical starter strains of Streptococcus thermophilus and Lactobacillus delbrueckii were the most abundant species in all batches. However, the fresh Brand-K cheeses had 1–3 log units higher thermophilic starter LAB counts than the ripened Brand-Z cheeses, which contained a more diverse viable LAB biota comprising Lacticaseibacillus paracasei, Leuconostocmesenteroides, Lentilactobacillus (L. diolivorans, L. kefiri, L. hilgardii), Pediococcusinopinatus/parvulus, few spontaneous nonstarter thermophilic streptococci and lactobacilli, and Enterococcus faecium and E. faecalis at higher subdominant levels.Conversely, the fresh Brand-K cheeses were enriched in members of the Lactiplantibacillus plantarum group; other LAB species were sporadically isolated, including Lactococcus lactis. All retail cheeses were safe (pH 3.9–4.0). No Salmonella spp. or Listeria monocytogenes were detected in 25-g samples by culture enrichment; however, Listeria innocua and coagulase-positive staphylococci (850 CFU/g) survived in one ripened batch. Gram-negative bacteria were <100 CFU/g in all cheeses. In conclusion, ripening reduced the starter LAB viability but increased the nonstarter LAB species diversity in the present Galotyri PDO market cheeses.

A novel angiotensin-I-converting enzyme inhibitory peptide from oyster: Simulated gastro-intestinal digestion, molecular docking, inhibition kinetics and antihypertensive effects in rats

In this study, a novel peptide, AEYLCEAC with high angiotensin-I-converting enzyme inhibitory (ACEI) activity was screened from oyster (Crassostrea gigas) hydrolysates, which was obtained from simulated gastro-intestinal digestion. Candidate peptides were confirmed to have a higher binding to angiotensin-I-converting enzyme (ACE) than the positive drug phosphoinic tripeptide calculated by Discovery Studio, and AEYLCEAC showed the highest ACE inhibition rate in vitro with a IC50 of 4.287 mM. Lineweaver-Burk plots confirmed that the peptidic inhibitory type of ACE is competitive. The molecular docking showed that ACEI activity of the AEYLCEAC was mainly due to the hydrogen bonding interactions with the active pockets (S1 and S2) of ACE. In vivo, AEYLCEAC effectively reduced diastolic blood pressure (DBP) and Systolic blood pressure (SBP) in hypertensive rats. These results indicate that AEYLCEAC might act as a helpful ingredient in functional foods or pharmaceuticals for the prevention and treatment of hypertension.

Microbial Ecology of Sheep Milk, Artisanal Feta, and Kefalograviera Cheeses. Part II: Technological, Safety, and Probiotic Attributes of Lactic Acid Bacteria Isolates

The aim of the present study was to examine 189 LAB strains belonging to the species Enterococcus faecium, E. faecalis, Lactococcus lactis, Pediococcus pentosaceus, Leuconostoc mesenteroides, Lactiplantibacillus pentosus, Latilactobacillus curvatus, Lp. plantarum, Levilactobacillus brevis, and Weissella paramesenteroides isolated form sheep milk, Feta and Kefalograviera cheeses at different ripening stages, for their technological compatibility with dairy products manufacturing, their activities that may compromise safety of the dairy products as well as their capacity to survive in the human gastrointestinal tract. For that purpose, milk acidification and coagulation capacity, caseinolytic, lipolytic, hemolytic, gelatinolytic, and bile salt hydrolase activity, production of exopolysaccharides, antimicrobial compounds, and biogenic amines, as well as acid and bile salt tolerance and antibiotic susceptibility were examined. The faster acidifying strains were Lc. lactis DRD 2658 and P. pentosaceus DRD 2657 that reduced the pH value of skim milk, within 6 h to 5.97 and 5.92, respectively. Strains able to perform weak caseinolysis were detected in all species assessed. On the contrary, lipolytic activity, production of exopolysaccharides, amino acid decarboxylation, hemolytic, gelatinase, and bile salt hydrolase activity were not detected. Variable susceptibility to the antibiotics examined was detected among LAB strains. However, in the majority of the cases, resistance was evident. None of the strains assessed, managed to survive to exposure at pH value 1. On the contrary, 25.9 and 88.9% of the strains survived after exposure at pH values 2 and 3, respectively; the reduction of the population was larger in the first case. The strains survived well after exposure to bile salts. The strain-dependent character of the properties examined was verified. Many strains, belonging to different species, have presented very interesting properties; however, further examination is needed before their potential use as starter or adjunct cultures.

In silico, in vitro and in vivo safety evaluation of Limosilactobacillus reuteri strains ATCC PTA-126787 & ATCC PTA-126788 for potential probiotic applications

The last two decades have witnessed a tremendous growth in probiotics and in the numbers of publications on their potential health benefits. Owing to their distinguishing beneficial effects and long history of safe use, species belonging to the Lactobacillus genus are among the most widely used probiotic species in human food and dietary supplements and are finding increased use in animal feed. Here, we isolated, identified, and evaluated the safety of two novel Limosilactobacillus reuteri (L. reuteri) isolates, ATCC PTA-126787 & ATCC PTA-126788. More specifically, we sequenced the genomes of these two L. reuteri strains using the PacBio sequencing platform. Using a combination of biochemical and genetic methods, we identified the two strains as belonging to L. reuteri species. Detailed in silico analyses showed that the two strains do not encode for any known genetic sequences of concern for human or animal health. In vitro assays confirmed that the strains are susceptible to clinically relevant antibiotics and do not produce potentially harmful by-products such as biogenic amines. In vitro bile and acid tolerance studies demonstrated that the two strains have similar survival profiles as the commercial L. reuteri probiotic strain DSM 17938. Most importantly, daily administration of the two probiotic strains to broiler chickens in drinking water for 26 days did not induce any adverse effect, clinical disease, or histopathological lesions, supporting the safety of the strains in an in vivo avian model. All together, these data provide in silico, in vitro and in vivo evidence of the safety of the two novel candidates for potential probiotic applications in humans as well as animals.

Dairy Lactic Acid Bacteria and Their Potential Function in Dietetics: The Food-Gut-Health Axis

Fermented dairy products are the good source of different species of live lactic acid bacteria (LAB), which are beneficial microbes well characterized for their health-promoting potential. Traditionally, dietary intake of fermented dairy foods has been related to different health-promoting benefits including antimicrobial activity and modulation of the immune system, among others. In recent years, emerging evidence suggests a contribution of dairy LAB in the prophylaxis and therapy of non-communicable diseases. Live bacterial cells or their metabolites can directly impact physiological responses and/or act as signalling molecules mediating more complex communications. This review provides up-to-date knowledge on the interactions between LAB isolated from dairy products (dairy LAB) and human health by discussing the concept of the food–gut-health axis. In particular, some bioactivities and probiotic potentials of dairy LAB have been provided on their involvement in the gut–brain axis and non-communicable diseases mainly focusing on their potential in the treatment of obesity, cardiovascular diseases, diabetes mellitus, inflammatory bowel diseases, and cancer.

Probiotics and Postbiotics as Substitutes of Antibiotics in Farm Animals: A Review

Simple Summary

Breeders are searching for methods to protect farming animals against diseases caused by pathogenic bacteria. The easiest way to fight bacteria is to use antibiotics. Unfortunately, their abuse results in the presence of bacteria resistant to the most commonly used antibiotics in the environment. The restrictions on the use of antibiotics have forced the search for natural and safe ways to protect animals. It has been shown that the use of probiotics based on lactic acid bacteria may have a positive effect on the growth and use of feed by broilers, on the stabilization of the intestinal microbiota of chickens and pigs, and in the prevention of mastitis in dairy cows. The use of probiotics (live, nonpathogenic microorganisms) and postbiotics (inanimate bacteria, cell components or post-fermentation by-products) reduces the occurrence of pathogens in large-scale farms.

Abstract

Since 2006, the use of growth-promoting antibiotics has been banned throughout the European Union. To meet the expectations of livestock farmers, various studies have been carried out with the use of lactic acid bacteria. Scientists are trying to obtain the antimicrobial effect against the most common pathogens in large-scale farms. Supplementing the diet of broilers with probiotics (live, nonpathogenic microorganisms) stabilized the intestinal microbiota, which improved the results of body weight gain (BWG) and feed intake (FI). The positive effect of probiotics based on lactic acid bacteria has been shown to prevent the occurrence of diarrhea during piglet weaning. The antagonistic activity of postbiotics (inanimate bacteria, cell components, or post-fermentation by-products) from post-culture media after lactobacilli cultures has been proven on Staphylococcus aureus—the pathogen most often responsible for causing mastitis among dairy cows. The article aims to present the latest research examining the antagonistic effect of lactic acid bacteria on the most common pathogens in broilers, piglets, pigs, and cow farms.

Diversity and Composition of Gut Bacterial Community in Giant Panda with Anorexia

The giant panda (GP) is the most precious animal in China. Gastrointestinal tract disease, especially associated with dysbiosis of gut microbiota, is the leading cause of death in GPs. Here, we performed 16S rRNA high-throughput sequencing to investigate the gut microbiota of GPs having symptoms of anorexia. Results showed that gut microbiota of GP with anorexia had lower richness (Chao1 index) than the healthy GP. However, no significant differences in alpha diversity were observed. There is a significance in the microbial structure between anorexia and healthy GPs. The abundance of phylum Firmicutes (99.23% ± 7.1%), unidentified genus Clostridiales (24.75% ± 2.5%), was significantly higher in the subadult anorexia group (P < 0.01), and that of the unidentified genus Clostridiales (4.53% ± 1.2%) was also significantly higher in the adult anorexia group (P < 0.01). Weissella and Streptococcus were found to be decreased in both anorexia groups. The decreased abundance of Weissella (0.02% ± 0.0%, 0.08% ± 0.0%) and Streptococcus (73.89% ± 4.3%, 91.15% ± 7.6%) and increase in Clostridium may cause symptoms of anorexia in giant pandas. The correlation analysis indicated that there is a symbiotic relationship among Streptococcus, Leuconostoc, Weissella, and Bacillus which are classified as probiotics (r > 0.6, P < 0.05). Importantly, a negative correlation has been found between Streptococcus and unidentified_Clostridium in two groups (r > 0.6, P < 0.05). Our results suggested that Streptococcus might be used as probiotics to control the growth of Clostridium causing the anorexia.

Invited review: Potential antiobesity effect of fermented dairy products

The growing prevalence of obesity affects millions of people around the world and has gained increased attention over the years because it is associated with the development of other chronic degenerative diseases. Different organizations recommend lifestyle changes to treat obesity; nevertheless, other strategies in addition to lifestyle changes have recently been suggested. One of these strategies is the use of probiotics in fermented dairy products; however, a need exists to review the different studies available related to the potential antiobesity effect of these products. Because probiotic fermented dairy products that support weight management are not available in the market, there is a great opportunity for the development of functional dairy products with new lactic acid bacteria that may present this added health benefit. Thus, the purpose of this overview is to highlight the importance of probiotic fermented dairy products as potential antiobesogenic functional foods and present in vitro and in vivo studies required before this kind of product may be introduced to the market. Overall, most studies attributed the antiobesity effect of fermented dairy foods to the probiotic strains present; however, bioactive peptides released during milk fermentation may also be responsible for this effect.

In vitro screening of probiotic properties of Lactobacillus plantarum isolated from fermented milk product

Objectives

The screening of traditional fermented products is essential for the assessment of safety, security, and further development of functional foods for the well-being of human health. The aim of the present study was to isolate and identify bacteria from fermented raw milk samples that exhibit health benefits upon consumption.

Methods

In order to confirm the isolates as probiotics, several in vitro assays were conducted to assess the probiotic properties of isolated bacteria. The initial screening includes tolerance to acid, bile, pancreatin, and NaCl. The cell surface properties demonstrate their interaction with mucosal epithelium, which includes hydrophobicity and auto-aggregation assay. Safety assessment was done by performing haemolytic test and antibiotic susceptibility test. The antagonistic activity of probiotic strain was further evaluated against some pathogenic bacteria.

Results

Lactobacillus plantarum (L. plantarum) isolated from fermented raw milk was preliminarily identified by biochemical tests and further confirmed using 16S rRNA identification. The isolate designated as L. plantarum strain GCC_19M1 demonstrated significant tolerance to low pH, 0.3% bile, 0.5% pancreatin, and 5% NaCl. In the presence of simulated gastric juice (at pH 3), the isolate exhibited a survival rate of 93.48–96.97%. Furthermore, the development of ecological niches in the human gut and their successful accumulation have been revealed by auto-aggregation and hydrophobicity properties. Absence of haemolytic activity ensures the non-virulent nature of the strain. Lactobacillus plantarum strain GCC_19M1 showed susceptibility towards gentamicin, tetracycline, kanamycin, meropenem, and ceftriaxone and exhibited an antagonistic effect on pathogenic bacteria.

Conclusion

The obtained results conveyed that L. plantarum strain GCC_19M1 has strong probiotic potential, and its presence in the fermented raw milk products may serve as a potent functional probiotic food.

Dietary Supplementation With Bacillus subtilis Direct-Fed Microbials Alters Chicken Intestinal Metabolite Levels

Direct-fed microbials (DFMs) are dietary supplements containing live microorganisms which confer a performance and health benefit to the host, but the mechanisms are unclear. Here, a metabolomics approach was used to identify changes in intestinal metabolite levels in chickens fed an unsupplemented diet or a diet supplemented with B. subtilis strain 1781 or strain 747. Body weight gains of chickens fed the B. subtilis-supplemented diets were increased up to 5.6% in the B. subtilis 1781 group and 7.6% in the B. subtilis 747 group compared with chickens fed the unsupplemented diet. Compared with unsupplemented controls, the levels of 83 metabolites were altered (p < 0.05) (25 increased, 58 decreased) in chickens given the B. subtilis 1781-supplemented diet, while 50 were altered (p < 0.05) (12 increased, 38 decreased) with the B. subtilis 747-supplemented diet. Twenty-two metabolites were altered (p < 0.05) (18 increased, 4 decreased) in the B. subtilis 1781 vs. B. subtilis 747 groups. A random forest analysis of the B. subtilis 1781 vs. control groups gave a predictive accuracy of 87.5%, while that of the B. subtilis 747 vs. control groups was 62.5%. A random forest analysis of the B. subtilis 1781 vs. B. subtilis 747 groups gave a predictive accuracy of 75.0%. Changes in the levels of these intestinal biochemicals provided a distinctive biochemical signature unique to each B. subtilis-supplemented group, and were characterized by alterations in the levels of dipeptides (alanylleucine, glutaminylleucine, phenylalanylalanine, valylglutamine), nucleosides (N1-methyladenosine, N6-methyladenosine, guanine, 2-deoxyguanosine), fatty acids (sebacate, valerylglycine, linoleoylcholine), and carbohydrates (fructose). These results provide the foundation for future studies to identify biochemicals that might be used to improve poultry growth performance in the absence of antibiotic growth promoters.

Bioprospecting for Bioactive Peptide Production by Lactic Acid Bacteria Isolated from Fermented Dairy Food

With rapidly ageing populations, the world is experiencing unsustainable healthcare from chronic diseases such as metabolic, cardiovascular, neurodegenerative, and cancer disorders. Healthy diet and lifestyle might contribute to prevent these diseases and potentially enhance health outcomes in patients during and after therapy. Fermented dairy foods (FDFs) found their origin concurrently with human civilization for increasing milk shelf-life and enhancing sensorial attributes. Although the probiotic concept has been developed more recently, FDFs, such as milks and yoghurt, have been unconsciously associated with health-promoting effects since ancient times. These health benefits rely not only on the occurrence of fermentation-associated live microbes (mainly lactic acid bacteria; LAB), but also on the pro-health molecules (PHMs) mostly derived from microbial conversion of food compounds. Therefore, there is a renaissance of interest toward traditional fermented food as a reservoir of novel microbes producing PHMs, and “hyperfoods” can be tailored to deliver these healthy molecules to humans. In FDFs, the main PHMs are bioactive peptides (BPs) released from milk proteins by microbial proteolysis. BPs display a pattern of biofunctions such as anti-hypertensive, antioxidant, immuno-modulatory, and anti-microbial activities. Here, we summarized the BPs most frequently encountered in dairy food and their biological activities; we reviewed the main studies exploring the potential of dairy microbiota to release BPs; and delineated the main effectors of the proteolytic LAB systems responsible for BPs release.

Piacentinu Ennese PDO Cheese as Reservoir of Promising Probiotic Bacteria

Piacentinu Ennese is a protected designation of origin (PDO) cheese produced in the surrounding area of Enna (Sicily, Italy), using raw ewe's milk without the addition of any starter cultures. In the present study, the Lactobacillus population of Piacentinu Ennese PDO cheese was in vitro screened in order to select promising probiotic strains to be further used in humans. One hundred and sixty-nine lactic acid bacteria (LAB) were isolated from 90 days ripened cheeses and identified by Rep-PCR genomic fingerprinting, using the (GTG)5-primer, and by MALDI-TOF MS. One hundred and thirteen (113) isolates belonging to QPS-list species were characterized for both safety and functional properties. All tested isolates were considered safe because none showed either gelatinase, DNase, mucinase, or hemolytic activity. Tolerance to lysozyme, bile salts, and acidic conditions, along with ability to survive under simulated gastrointestinal digestion, were observed. In addition, based on antimicrobial activity against pathogens, cell surface characteristics, Caco-2 adhesion abilities, and anti-inflammatory potential, it was possible to confirm the strain-dependent functional aptitude, suggesting that Piacentinu Ennese PDO cheese may be considered a precious source of probiotic candidates.

Goat Milk with Different Alpha-s1 Casein Genotype (CSN1S1) Fermented by Selected Lactobacillus paracasei as Potential Functional Food

The characteristics of fermented milk are affected by the type of milk used and the microorganisms involved in the fermentation process. Goat milk has been widely suggested as a possible alternative to cow milk in allergic subjects, because of the high genetic variability in alpha-s1 casein (CSN1S1) content, which is associated with different technological and nutritional properties of milk. The aim of the study was to evaluate the suitability of goat milk with low and high CSN1S1 to produce fermented milk. In addition, the performance as starter of selected Lactobacillus paracasei FS109 strain compared to no-selected L. paracasei strains was investigated. Initially, the selected L. paracasei FS109 strain was tested for adhesion ability to HT-29 and Caco-2 cells and immunomodulation effect. Then, the strain was used to produce fermented milk from goat milk with a low and high casein CSN1S1 genotype. The results indicated that greater acidifying activity was obtained for L. paracasei FS109 after 24 h of fermentation than the other two strains tested independently by the CSN1S1 genotype. L. paracasei FS109 grew well during fermentation, reaching a higher value (>8.5 log CFU/mL). Interestingly, the same strain maintained a high viable population (about 9 log CFU/mL) during the 30-day cold storage of the product. The present study shows for the first time the suitability of the goat milk with low CSN1S1 genotypes to produce fermented milk and highlight the importance of strain selection in determination of technological and beneficial traits. Combining goat milk with low CSN1S1 and selected strains could be a strategy of improving traditional and functional fermented milk market.

Production of Bioactive Peptides from Lactic Acid Bacteria: A Sustainable Approach for Healthier Foods

Traditional fermented foods where lactic acid bacteria (LAB) are present have been associated with beneficial effects on human health, and some of those benefits are related to protein-derived products. Peptides produced by LAB have attracted the interest of food industries because of their diverse applications. These peptides include ribosomally produced (bacteriocins) and protein hydrolysates by-products (bioactive peptides), which can participate as natural preservatives and nutraceuticals, respectively. It is essential to understand the biochemical pathways and the effect of growth conditions for the production of bioactive peptides and bacteriocins by LAB, in order to suggest strategies for optimization. LAB is an important food-grade expression system that can be used in the simultaneous production of peptide-based products for the food, animal, cosmetic, and pharmaceutical industries. This review describes the multifunctional proteinaceous compounds generated by LAB metabolism and discusses a strategy to use a single-step production process, using an alternative protein-based media. This strategy will provide economic advantages in fermentation processes and will also provide an environmental alternative to industrial waste valorization. New technologies that can be used to improve production and bioactivity of LAB-derived peptides are also analyzed.

Streptococcus macedonicus strains isolated from traditional fermented milks: resistance to gastrointestinal environment and adhesion ability

In this study, Streptococcus macedonicus (S. macedonicus) strains were identified from Algerian traditional fermented milks (Lben and Rayeb). Important prerequisites of probiotic interest such as acidity, bile salts tolerance, and adhesion ability to epithelial cells were investigated. A combination of phenotypic (ability to grow on Bile Esculin Azide medium, BEA; on high salt content medium NaCl 6.5%; on alkaline medium pH 9.6) and genotypic approaches (16S rRNA, ITS genes sequencing and MLST technique) allowed to identify four genetically distinct strains of S. macedonicus. These four strains and two references, Streptococcus thermophilus LMD-9 and Lactobacillus rhamnosus GG (LGG), were tested for their capacity to survive at low pH values, and at different concentrations of an equimolar bile salts mixture (BSM). Two different cell lines, Caco-2 TC7 and HT29-MTX, were used for the adhesion study. The results show that S. macedonicus strains selected constitute a distinct genetic entity from the Greek strain S. macedonicus ACA-DC-198. They were able to survive up to pH 3 and could tolerate high concentrations of bile salts (10 mM), unlike LMD-9 and LGG strains. Our strains also display in vitro adhesion similar to the LGG strain on Caco-2 TC7 and higher adhesion than the LMD-9 strain to Caco-2 TC7 and HT29-MTX cell models. This first characterization allows considering S. macedonicus as a potential candidate for possible probiotic effects that need to be investigated.

Food-Origin Lactic Acid Bacteria May Exhibit Probiotic Properties: Review

One of the most promising areas of development in the human nutritional field over the last two decades has been the use of probiotics and recognition of their role in human health and disease. Lactic acid-producing bacteria are the most commonly used probiotics in foods. It is well known that probiotics have a number of beneficial health effects in humans and animals. They play an important role in the protection of the host against harmful microorganisms and also strengthen the immune system. Some probiotics have also been found to improve feed digestibility and reduce metabolic disorders. They must be safe, acid and bile tolerant, and able to adhere and colonize the intestinal tract. The means by which probiotic bacteria elicit their health effects are not understood fully, but may include competitive exclusion of enteric pathogens, neutralization of dietary carcinogens, production of antimicrobial metabolites, and modulation of mucosal and systemic immune function. So far, lactic acid bacteria isolated only from the human gastrointestinal tract are recommended by the Food and Agriculture Organization (FAO) and World Health Organization (WHO) for use as probiotics by humans. However, more and more studies suggest that strains considered to be probiotics could be isolated from fermented products of animal origin, as well as from non-dairy fermented products. Traditional fermented products are a rich source of microorganisms, some of which may exhibit probiotic properties. They conform to the FAO/WHO recommendation, with one exception; they have not been isolated from human gastrointestinal tract. In light of extensive new scientific evidence, should the possibility of changing the current FAO/WHO requirements for the definition of probiotic bacteria be considered?