Metabolites produced during the growth of probiotics in cocoa supplementation and the limited role of cocoa in host-enteric bacterial pathogen interactions

Dark chocolate's impact on low-grade endotoxemia in metabolic dysfunction-associated steatohepatitis

BACKGROUND AND AIMS

Cocoa may have prebiotic effects and improve gut barrier function. However, it remains unclear whether dark chocolate can reduce lipopolysaccharide (LPS) levels in patients with metabolic dysfunction-associated steatohepatitis (MASH). This study aims to evaluate the effect of dark chocolate compared to milk chocolate on endotoxemia in patients with MASH.

METHODS AND RESULTS

Nineteen patients with MASH were randomly assigned in a crossover design to consume either 40 g/d of dark chocolate (>85% cocoa) or 40 g/d of milk chocolate (<35% cocoa) for 2 weeks to evaluate circulating levels of LPS and zonulin. A significant difference between treatments was observed in LPS (P = 0.04) and zonulin (P = 0.02) levels based on the ANOVA conducted on the crossover study data. Pairwise comparisons revealed that, compared to baseline, after 14 days of dark chocolate consumption, LPS levels decreased from 22 ± 4 to 19 ± 4 pg/dL (-15%), and zonulin levels decreased from 3.2 ± 0.9 to 2.5 ± 0.8 pg/mL (-20%). Linear correlation analysis indicated that the change (Δ) in LPS values before and after chocolate intake correlated with the change (Δ) in zonulin levels (R = 0.340, P = 0.03).

CONCLUSIONS

This study demonstrates that dark chocolate reduces circulating levels of LPS and zonulin in patients with MASH.

Effects of short-term, high-dose cocoa-derived flavanol supplementation on gut microbiota composition: secondary findings from a randomized, double-blind, placebo-controlled crossover study

Cocoa-derived flavanols (CDF) may act as prebiotics. However, evidence is inconsistent, and the duration and dose of CDF intake needed to elicit any prebiotic effect are undefined. This randomized, double-blind, crossover study determined the effects of short-term, high-dose dietary supplementation with CDF versus matched placebo on gut microbiota composition in 8 healthy adults. A single faecal sample was collected 8 d after supplementation with 900 mg/d CDF or placebo. Gut microbiota composition and Bifidobacterium spp. and Lactobacillus spp. abundance were measured as secondary outcomes by 16S ribosomal ribonucleic acid (rRNA) amplicon sequencing and quantitative polymerase chain reaction, respectively. No between-treatment differences in the relative or absolute abundance of Bifidobacterium spp. (Cohen's d = 0.89, P = 0.22) or Lactobacillus spp. (Cohen's d = 0.42, P = 0.65) were detected. Shannon diversity (Cohen's d = 0.38, P = 0.04) and overall community richness (Cohen's d = 0.34, P = 0.06) were lower following CDF supplementation versus placebo, but no between-treatment differences in β-diversity or taxa relative abundances were observed. Findings are not consistent with a clear prebiotic effect of this short-term, high-dose CDF supplementation strategy relative to placebo.

Interactions between Dietary Antioxidants, Dietary Fiber and the Gut Microbiome: Their Putative Role in Inflammation and Cancer

The intricate relationship between the gastrointestinal (GI) microbiome and the progression of chronic non-communicable diseases underscores the significance of developing strategies to modulate the GI microbiota for promoting human health. The administration of probiotics and prebiotics represents a good strategy that enhances the population of beneficial bacteria in the intestinal lumen post-consumption, which has a positive impact on human health. In addition, dietary fibers serve as a significant energy source for bacteria inhabiting the cecum and colon. Research articles and reviews sourced from various global databases were systematically analyzed using specific phrases and keywords to investigate these relationships. There is a clear association between dietary fiber intake and improved colon function, gut motility, and reduced colorectal cancer (CRC) risk. Moreover, the state of health is reflected in the reciprocal and bidirectional relationships among food, dietary antioxidants, inflammation, and body composition. They are known for their antioxidant properties and their ability to inhibit angiogenesis, metastasis, and cell proliferation. Additionally, they promote cell survival, modulate immune and inflammatory responses, and inactivate pro-carcinogens. These actions collectively contribute to their role in cancer prevention. In different investigations, antioxidant supplements containing vitamins have been shown to lower the risk of specific cancer types. In contrast, some evidence suggests that taking antioxidant supplements can increase the risk of developing cancer. Ultimately, collaborative efforts among immunologists, clinicians, nutritionists, and dietitians are imperative for designing well-structured nutritional trials to corroborate the clinical efficacy of dietary therapy in managing inflammation and preventing carcinogenesis. This review seeks to explore the interrelationships among dietary antioxidants, dietary fiber, and the gut microbiome, with a particular focus on their potential implications in inflammation and cancer.

The synergistic effects of polyphenols and intestinal microbiota on osteoporosis

Osteoporosis is a common metabolic disease in middle-aged and elderly people. It is characterized by a reduction in bone mass, compromised bone microstructure, heightened bone fragility, and an increased susceptibility to fractures. The dynamic imbalance between osteoblast and osteoclast populations is a decisive factor in the occurrence of osteoporosis. With the increase in the elderly population in society, the incidence of osteoporosis, disability, and mortality have gradually increased. Polyphenols are a fascinating class of compounds that are found in both food and medicine and exhibit a variety of biological activities with significant health benefits. As a component of food, polyphenols not only provide color, flavor, and aroma but also act as potent antioxidants, protecting our cells from oxidative stress and reducing the risk of chronic disease. Moreover, these natural compounds exhibit anti-inflammatory properties, which aid in immune response regulation and potentially alleviate symptoms of diverse ailments. The gut microbiota can degrade polyphenols into more absorbable metabolites, thereby increasing their bioavailability. Polyphenols can also shape the gut microbiota and increase its abundance. Therefore, studying the synergistic effect between gut microbiota and polyphenols may help in the treatment and prevention of osteoporosis. By delving into how gut microbiota can enhance the bioavailability of polyphenols and how polyphenols can shape the gut microbiota and increase its abundance, this review offers valuable information and references for the treatment and prevention of osteoporosis.

Interactions between polyphenols from Theobroma cacao and Lactobacillales to evaluate the potential of a combined strategy for intestinal free-fatty acid removal

Reducing the absorption of lipids in the gastrointestinal tract is one approach used to manage caloric intake in the fight against excessive weight. Biocompounds, such as polyphenols and probiotics, have been used in this regard. However, some studies have reported that polyphenols have both inhibitory and stimulatory effects on bacterial growth. This study aimed to investigate the resistance to polyphenol-rich extracts from Theobroma cacao L. of Lactobacillales isolated from the human fecal microbiota of lean volunteers (with high saturated fat consumption), to further the knowledge of the potential combination of these bioactive compounds. The strains were selected using an improved and affordable strategy that allowed the rapid screening of strains with fat-removing capacity. Among 1400 isolates, two strains, Lactobacillus sp. A1 and Pediococcus acidilactici E1, were selected due to their capacity to remove saturated fats from the culture media similar to the reference strain Lactobacillus sp. JBD301. Both isolated strains differed in their resistance to cocoa polyphenols: the extract did not affect the growth of strain A1, but reduced the growth of strain E1. However, the extract did not affect the level of in vitro fat removal by either strain, confirming the potential use of a combination of bacteria and polyphenols as a promising strategy for the intestinal removal of free fatty acids.

The Effect of Delivery Matrix on Bifidobacterium animalis subsp. lactis HN019 Survival through In Vitro Human Digestion

Bifidobacterium animalis subsp. lactis HN019 is a probiotic with several documented human health benefits. Interest in probiotics has led to the development of new formats that probiotics, including HN019, can be supplemented into. In this study, we looked at common HN019 formats such as frozen culture and freeze-dried powder as well as supplementing it into the following food matrices: yogurts (dairy, soy, and oat based), xanthan gum-based tablets, pulpless orange juice, whey sports drink, and dark chocolate (70% cocoa). In this work, our aim was to investigate whether the food matrix that carried HN019 via simulated human digestion (a dual model system mimicking both upper and lower gastrointestinal digestion) influenced probiotic delivery. To that end, we validated and used a real-time qPCR assay to detect HN019 after simulated digestion. In addition, we also measured the effect on a panel of metabolites. After simulated digestion, we were able to detect HN019 from all the matrices tested, and the observed changes to the metabolite profile were consistent with those expected from the food matrix used. In conclusion, this work suggests that the food matrix supplemented with HN019 did not interfere with delivery to the colon via simulated human digestion.

Alternative approaches to therapeutics and subtherapeutics for sustainable poultry production

The world population is growing rapidly and thus its demand for food is growing as well. To meet the demand of the ever-increasing number of consumers, the poultry industry and both of its main sectors-conventional and organic/cage-free farming-are expanding in parallel. Due to increasing demand of poultry products and higher mortality rate of chicks (an average 0.3% increase of mortality over last 5 yr), both conventional and organic poultry farming systems struggle with various issues; animal welfare, environmental sustainability, and antibiotic resistance of the prevailing zoonotic/enteric pathogens are common issues for conventional farming whereas slow growth rate, higher costs, inefficient land use, different diseases of the chicken, and cross-contamination with bacterial pathogens into the final products are the major issues for organic poultry farming. On top of these issues, the use of subtherapeutic antibiotics was recently banned in conventional farming systems and by definition the organic farming system cannot use the antibiotics/synthetic chemicals even for therapeutic use. In conventional farming system, use of therapeutic antibiotics may result in residuals antibiotics in the final products. As a result, sustainable alternatives are in demand to mitigate the prevailing issues for both conventional and organic farming. Potential alternatives may include bacteriophages, vaccination, probiotics, plant-derived prebiotics, and synbiotics. These alternatives have beneficial attributes and shortcomings of their use in both conventional and organic poultry production system. In this review, we'll discuss the scope of these potential alternatives as therapeutics and subtherapeutics in sustainable poultry production and ways to improve their efficacy.

Impact of Lactobacillus-originated metabolites on enterohemorrhagic E. coli in rumen fluid

Rumen is one of the richest microbial ecosystems naturally harboring many zoonotic pathogens. Controlling the colonization of cattle originated zoonotic pathogens in rumen, particularly enterohemorrhagic Escherichia coli (EHEC), is critical in reducing foodborne enteric diseases in humans. In this study, we aimed to inhibit the growth of EHEC in a simulated rumen system with collected rumen fluids (RFs) using live probiotics, synbiotics, and their metabolites. EHEC inoculated RF was treated with live wild type Lactobacillus casei (LCwt), LCwt with 0.5% peanut flour (LCwt+PF), an engineered LC capable of overexpressing linoleate isomerase (LCCLA), and their metabolites collected in cell-free culture supernatants (CFCSwt, CFCSwt+PF, and CFCSCLA) at various time points. A growth stimulatory effect toward Lactobacillus spp. was exerted by all CFCS, while the EHEC was suppressed. Among other treatments only LCwt+PF reduced EHEC by 2.68 logs after 72 h. This observation was also supported by metataxonomic analysis. A reduction in Bacteroidetes and Proteobacteria while increase in Firmicutes was observed at 48 h by the presence of CFCSs as compared to the control. Our observation implies probiotic-originated metabolites modulate rumen microbiota positively which can be deployed to control the transmission of cattle-borne pathogens specifically EHEC.

Cocoa seeds and chocolate products interaction with gut microbiota; mining microbial and functional biomarkers from mechanistic studies, clinical trials and 16S rRNA amplicon sequencing

In recent years, gut microbiome has evolved as a focal point of interest with growing recognition that a well-balanced gut microbiota is highly relevant to an individual's health status. The present review provides a mechanistic insight on the effects of cocoa chemicals on the gut microbiome and further reveals in silico biomarkers, taxonomic and functional features that distinguish gut microbiome of cocoa consumers and controls by using 16S rRNA gene sequencing data. The polyphenols in cocoa can change the gut microbiota either by inhibiting the growth of pathogenic bacteria in the gut such as Clostridium perfringens or by increasing the growth of beneficial microbiota in the gut such as Lactobacillus and Bifidobacterium. This paper demonstrates the holistic effect of gut microbiota on cocoa chemicals and how it impacts human health. We present herein the first comprehensive review and analysis of how raw and roasted cocoa and its products can specifically influence gut homeostasis, and likewise, how microbiota metabolizes cocoa chemicals. In addition to that, our 16S rRNA amplicon sequencing analysis revealed that the flavone and flavonols metabolism, aminobenzoate degradation and fatty acid elongation pathways represent the three most important signatures of microbial functions associated with cocoa consumption.

Antagonistic Effects of Conjugated Linoleic Acids of Lactobacillus casei against Foodborne Enterohemorrhagic Escherichia coli

ABSTRACT

Probiotics in fermented foods or commercially available supplements benefit the host by providing metabolites and peptides. The production of these metabolites varies with the available substrates or prebiotics present in the system and their concentration. In this study, 0.5% peanut flour (PF) was used to stimulate the growth and production of metabolites of wild-type Lactobacillus casei (LCwt) and compare with an engineered L. casei (LCCLA) capable of converting a higher amount of conjugated linoleic acid (CLA). The total extracellular metabolites present in the cell-free cultural supernatant (CFCS) of LCwt (without peanut), LCwt+PF (with peanut), and LCCLA were collected after 24 and 48 h of incubation, and their antagonistic activities against enterohemorrhagic Escherichia coli (EHEC EDL933) growth and pathogenesis were evaluated. All collected metabolites exhibited varying efficiency in restraining EHEC EDL933 growth, whereas supplementing a low concentration of CLA to the 48-h CFCS from LCwt showed augmented antagonism toward EHEC EDL933. A downregulation of key virulence genes was observed from metabolites collected at the 48-h time point. These observations indicate that the presence of metabolites in CFCSs-including CLA, which is produced by Lactobacillus and was identified by gas chromatography-mass spectrometry-plays a critical role. This study demonstrates the potential applicability of Lactobacillus-originated CLA in the prevention of EHEC EDL933-mediated illnesses.

HIGHLIGHTS

Micronutrient Content and Total Lactic Acid Bacteria of Dadiah Pudding as Food Supplementation for Pregnant Women

BACKGROUND: Dadiah, traditional yogurt from Indonesia, which is known as a source of probiotics, also contains micronutrients. AIM: This descriptive study aimed to determine whether additional ingredients and processes during the manufacture of Dadiah pudding maintain the iron, zinc, calcium, and total lactic acid bacteria (LAB) contents. METHODS: Dadiah pudding was made using Dadiah originated from Bukittinggi, West Sumatra. Micronutrient levels were analyzed according to Indonesian National Standard 01-2896-1998. The total LAB were counted by inoculating samples on Man, Rogosa, and Sharpe agar with serial dilution, and morphological identification was carried out using gram stain. RESULTS: In 100 g of original Dadiah, mango and chocolate Dadiah pudding contained 347.98, 276.61, and 279.29 mg of calcium; 4.87, 3.75, and 6.31 mg of zinc; 6.53, 6.60, and 9.39 mg of iron; and 6.4 × 10⁹, 6.1 × 10⁹, and 2.4 × 10⁹ CFU/ml LAB, respectively. CONCLUSION: This study found that modifying the original Dadiah into Dadiah pudding has been proved to affect the concentration of calcium, zinc, and iron and to maintain total LAB. We suggest that consuming Dadiah pudding may be a good choice as a food supplementation for pregnant women to optimize the golden period outcomes.

Role of Food Antioxidants in Modulating Gut Microbial Communities: Novel Understandings in Intestinal Oxidative Stress Damage and Their Impact on Host Health

Dietary components have an important role on the structure and function of host gut microbial communities. Even though, various dietary components, such as carbohydrates, fats, proteins, fibers, and vitamins, have been studied in depth for their effect on gut microbiomes, little attention has been paid regarding the impact of several food antioxidants on the gut microbiome. The long-term exposure to reactive oxygen species (ROS) can cause microbial dysbiosis which leads to numerous intestinal diseases such as microbiota dysbiosis, intestinal injury, colorectal cancers, enteric infections, and inflammatory bowel diseases. Recently, it has been shown that the food derived antioxidant compounds might protect the host from intestinal oxidative stress via modulating the composition of beneficial microbial species in the gut. The present review summarizes the impact of food antioxidants including antioxidant vitamins, dietary polyphenols, carotenoids, and bioactive peptides on the structure as well as function of host gut microbial communities. Several in vitro, animal model, and clinical studies indicates that food antioxidants might modify the host gut microbial communities and their health status. However, still further clarification is needed as to whether changes in certain microbial species caused by food additives may lead to changes in metabolism and immune function.

Understanding the Gastrointestinal Protective Effects of Polyphenols using Foodomics-Based Approaches

Plant polyphenols are rich sources of natural anti-oxidants and prebiotics. After ingestion, most polyphenols are absorbed in the intestine and interact with the gut microbiota and modulated metabolites produced by bacterial fermentation, such as short-chain fatty acids (SCFAs). Dietary polyphenols immunomodulatory role by regulating intestinal microorganisms, inhibiting the etiology and pathogenesis of various diseases including colon cancer, colorectal cancer, inflammatory bowel disease (IBD) and colitis. Foodomics is a novel high-throughput analysis approach widely applied in food and nutrition studies, incorporating genomics, transcriptomics, proteomics, metabolomics, and integrating multi-omics technologies. In this review, we present an overview of foodomics technologies for identifying active polyphenol components from natural foods, as well as a summary of the gastrointestinal protective effects of polyphenols based on foodomics approaches. Furthermore, we critically assess the limitations in applying foodomics technologies to investigate the protective effect of polyphenols on the gastrointestinal (GI) system. Finally, we outline future directions of foodomics techniques to investigate GI protective effects of polyphenols. Foodomics based on the combination of several analytical platforms and data processing for genomics, transcriptomics, proteomics and metabolomics studies, provides abundant data and a more comprehensive understanding of the interactions between polyphenols and the GI tract at the molecular level. This contribution provides a basis for further exploring the protective mechanisms of polyphenols on the GI system.

Chemical and biological properties of cocoa beans affected by processing: a review

Cocoa (Theobroma cacao L.) is widely cultivated in tropical countries. The cocoa beans are a popular ingredient of confectionery. Cocoa beans contain various chemicals that contribute to their bioactivity and nutritional properties. There has been increasing interest in developing cocoa beans for "healthy" food products. Cocoa beans have special combination of nutrients such as lipids, carbohydrates, proteins and other compounds of biological activities. The bioactive phytochemicals include methylxanthines, polyphenols, biogenic amines, melanoidins, isoprostanoids and oxalates. These phytochemicals of cocoa are related to various in vivo and in vitro biological activities such as antioxidation, anti-cancer, anti-microbial, anti-inflammation, anti-diabetes, cardiovascular protection, physical improvement, anti-photoaging, anti-depression and blood glucose regulation. The potential of bioactive compounds in cocoa remains to be maximized for food and nutritional applications. The current processing technology promotes the degradation of beneficial bioactive compounds, while maximizing the flavors and its precursors. It is not optimized for the utilization of cocoa beans for "healthy" product formulations. Modifications of the current processing line and non-conventional processing are needed to better preserve and utilize the beneficial bioactive compounds in cocoa beans.

Competitive reduction of poultry-borne enteric bacterial pathogens in chicken gut with bioactive Lactobacillus casei

In this study, the effect of sustainable probiotics on Campylobacter jejuni colonization and gut microbiome composition was evaluated using chicken as a model organism. Chickens were given Lactobacillus casei over-expressing myosin-cross-reactive antigen (LC+mcra). LC+mcra can generate bioactive compounds in larger quantity including conjugated linoleic acid. A total of 120 chickens were used in duplicate trials to investigate the effectiveness of LC+mcra in decreasing C. jejuni colonization by means of kanamycin resistant strain compared to the control group. We observed that LC+mcra can efficiently colonize various parts of the chicken gut and competitively reduce colonization of natural and challenged C. jejuni and natural Salmonella enterica. LC+mcra was found to reduce C. jejuni colonization in cecum, ileum and jejunum, by more than one log CFU/g when compared to the no-probiotic control group. Furthermore, 16S rRNA compositional analysis revealed lower abundance of Proteobacteria, higher abundance of Firmicutes, along with enriched bacterial genus diversity in gut of LC+mcra fed chicken. Decreased contamination of drinking water by C. jejuni and S. enterica was also observed, suggesting a potential function of reducing horizontal transfer of enteric bacteria in poultry. Outcomes of this study reveal high potential of LC+mcra as sustainable approach to decrease colonization of C. jejuni and S. enterica in poultry gut along with other beneficial attributes.

Cocoa Polyphenols and Gut Microbiota Interplay: Bioavailability, Prebiotic Effect, and Impact on Human Health

Cocoa and its products are rich sources of polyphenols such as flavanols. These compounds exert antioxidant and anti-inflammatory activities, accountable for cocoa health-promoting effects. However, cocoa polyphenols are poorly absorbed in the intestine, and most of them cannot reach the systemic circulation in their natural forms. Instead, their secondary bioactive metabolites are bioavailable, enter the circulation, reach the target organs, and exhibit their activities. In fact, once reaching the intestine, cocoa polyphenols interact bidirectionally with the gut microbiota. These compounds can modulate the composition of the gut microbiota exerting prebiotic mechanisms. They enhance the growth of beneficial gut bacteria, such as Lactobacillus and Bifidobacterium, while reducing the number of pathogenic ones, such as Clostridium perfringens. On the other hand, bioactive cocoa metabolites can enhance gut health, displaying anti-inflammatory activities, positively affecting immunity, and reducing the risk of various diseases. This review aims to summarize the available knowledge of the bidirectional interaction between cocoa polyphenols and gut microbiota with their various health outcomes.

Prevention of enteric bacterial infections and modulation of gut microbiota with conjugated linoleic acids producing Lactobacillus in mice

Probiotics are recognized for outcompeting pathogenic bacteria by competitive receptor-mediated colonization and secretion of functional metabolites which are antimicrobial against certain microbes as well as improving host's gut health and immunity. Recently, we have constructed a bioactive Lactobacillus casei (LC) strain, LC^+mcra , by inserting mcra (myosin cross-reactive antigen) gene, which stimulates the conversion of conjugated linoleic acids. In this study, we evaluated the modulation of gut microbiome and protective roles of LC^+mcra against pathogenic Salmonella enterica serovar Typhimurium (ST) and enterohemorrhagic E. coli (EHEC) infections in BALB/cJ mice. We observed that LC^+mcra colonized efficiently in mice gut intestine and competitively reduced the infection with ST and EHEC in various locations of small and large intestine, specifically cecum, jejunum, and ileum (p < 0.05). Positive modulation of the cecal microbiota, for example, higher relative abundances of Firmicutes, lower relative abundances of Proteobacteria, and increased bacterial species diversity/richness, was detected in ST-challenged mice pretreated with LC^+mcra based on 16S metagenomic sequencing. Cytokine gene expression analysis indicated that mice pretreated with LC^+mcra associated with attenuated bacterial pathogen-induced gut inflammation. Furthermore, mice fed daily with LC^+mcra for one week could protect themselves from the impairments caused by enteric infections with ST or EHEC. These impairments include weight loss, negative hematological changes, intestinal histological alterations, and potential death. This in vivo study suggests that daily consumption of novel conjugated linoleic acids over-producing probiotic effectively improves intestinal microbiota composition and prevents/combats foodborne enteric bacterial infections with pathogenic Salmonella and diarrheagenic E. coli.

Limiting the pathogenesis of Salmonella Typhimurium with berry phenolic extracts and linoleic acid overproducing Lactobacillus casei

The growing threat of emergent multidrug-resistant enteric bacterial pathogens, and their adopted virulence properties are directing to find alternative antimicrobials and/or development of dietaries that can improve host gut health and/or defense. Recently, we found that modified Lactobacillus casei (Lc + CLA) with increased production of conjugated linoleic acid has antimicrobial and other beneficial properties. Further, prebiotic alike products such as berry pomace extracts (BPEs), increase the growth of probiotics and inhibit the growth of certain bacterial pathogens. In this study, we evaluated the antibacterial effect of genetically modified Lc + CLA along with BPEs against major enteric pathogen Salmonella enterica serovar Typhimurium (ST). In mixed culture condition, the growth of ST was significantly reduced in the presence of Lc + CLA and/or BPEs. Bacterial cell-free cultural supernatant (CFCS) collected from wild-type Lc or modified Lc + CLA strains also inhibited the growth and survival of ST, and those inhibitory effects were enhanced in the presence of BPEs. We also found that the interaction of the pathogen with cultured host (HD-11 and INT-407) cells were also altered in the presence of either Lc or Lc + CLA strain or their CFCSs significantly. Furthermore, the relative expression of genes related to ST virulence and physicochemical properties of ST was altered by the effect of CFCSs of either Lc or Lc + CLA. These findings indicate that a diet containing synbiotic, specifically linoleic acid, over-produced Lc + CLA and prebiotic product BPEs, might have the potential to be effective in controlling ST growth and pathogenesis.

Dietary probiotic and metabolites improve intestinal homeostasis and prevent colorectal cancer

Metabolites from Lactobacillus casei display substantial antioxidant and anti-inflammatory activities, inhibit colorectal cancer cell proliferation and growth, and modulate gut microfloral composition, specifically reducing sulfidogenic bacteria.

Antimicrobial Effect and Probiotic Potential of Phage Resistant Lactobacillus plantarum and its Interactions with Zoonotic Bacterial Pathogens

Development of phage-resistant probiotic particularly Lactobacillus is an alternative approach to enhance their beneficial effects as in animal feed supplements. In this study, we developed phage-resistant Lactobacillus plantarum (LP^+PR) mutant and compared their antimicrobial effects and probiotic potential against zoonotic bacterial pathogens including Salmonella enterica serovar Typhimurium, enterohemorrhagic Escherichia coli (EHEC), Staphylococcus aureus, and Listeria monocytogenes with phage-sensitive L. plantarum (LP) strain. LP^+PR strain showed markedly higher growth rate than wild-type LP strain. In co-culture with LP^+PR and in the presence of cell-free cultural supernatants (CFCSs) of LP^+PR, the growth of S. Typhimurium, EHEC, S. aureus, and L. monocytogenes were reduced significantly (P < 0.05). The adhesion ability of LP^+PR was slightly higher than the LP on human epithelial INT-407 cells. Most importantly, LP^+PR strain significantly inhibited the adhesive and invasive abilities of all four zoonotic pathogens to INT-407 cells (P < 0.05). Moreover, real-time qPCR revealed that in the presence of LP^+PR strain or its CFCSs, expression of virulence genes of these zoonotic bacterial pathogens were suppressed significantly (P < 0.05). These findings suggest that the LP^+PR strain is capable of inhibiting major zoonotic bacterial pathogens efficiently and would be a potential candidate for industrial usage in animal production or fermentation.

Effect of conjugated linoleic acid overproducing Lactobacillus with berry pomace phenolic extracts on Campylobacter jejuni pathogenesis

Campylobacter jejuni (CJ) is one of the predominant causative agents of acute gastroenteritis in the US and other developed countries through the handling of raw chicken or the consumption of undercooked poultry and poultry products. Probiotics and their metabolites such as conjugated linoleic acids (CLAs) play a crucial role in improving host health and act as antimicrobials against enteric pathogens. Furthermore, prebiotics or prebiotic-like components such as bioactive phenolics from berry pomace can stimulate the growth of beneficial microbes including Lactobacillus casei (LC) and its metabolites, and competitively inhibit the growth of enteric bacterial pathogens. In this study, we aimed at enhancing the efficiency of antimicrobial/beneficial activities of LC and the extent of production of bioactive compounds by combining berry pomace phenolic extract (BPPE) and overproducing CLA in L. casei (LC-CLA). Under mixed culture conditions, LC-CLA in the presence of BPPE reduced the growth of CJ by more than 3 log CFU ml-1 within 48 h. The cell-free culture supernatant (CFCS) of LC-CLA in the presence of BPPE also reduced significantly the growth of CJ >3.2 log CFU ml-1 at 24 h. The interactions of CJ with cultured chicken fibroblast cells (DF-1), chicken macrophage (HD-11), and human epithelial cells (HeLa) were altered significantly. Treatments with BPPE and/or CFCS also altered the injured cell number, auto-aggregation capacity and cell surface hydrophobicity of CJ, significantly. Furthermore, combined treatments with BPPE and CFCSs of LC-CLA altered the expression of multiple virulence genes such as ciaB, cdtB, cadF, flaA, and flaB of CJ from 0.45 fold to 6.85 fold. Overall, BPPE enhanced the effect of LC-CLA in the reduction of CJ growth, survival ability, host cell-CJ interactions, and virulence gene expression. This finding indicates that a combination of BPPE and LC-CLA may be able to prevent the colonization of CJ in poultry, reduce the cross-contamination of poultry products and control poultry-borne campylobacteriosis in humans.

Linoleic Acids Overproducing Lactobacillus casei Limits Growth, Survival, and Virulence of Salmonella Typhimurium and Enterohaemorrhagic Escherichia coli

Probiotics, particularly lactic acid bacteria, are biologic agents which limit the growth, virulence, and survival/colonization of various enteric bacterial pathogens and serve as potential alternatives to antibiotics. Mechanisms that contribute to this antimicrobial effect include producing bioactive metabolites/acids, increasing nutrient and receptor-mediated competition, and modulating gut microbiome ecology. However, these functions of common probiotic strains are limited due to the finite quantity of metabolites they produce and their total number in the gut ecosystem. Conjugated linoleic acids (CLAs), critical metabolites of Lactobacillus, have multiple beneficial effects on human health including anti-carcinogenesis, anti-inflammation, anti-oxidation, and anti-pathogenicity. In this study, we aim to overexpress the myosin cross-reactive antigen gene (mcra) in Lactobacillus casei (LC) to enhance the production of CLA and investigate its effectiveness against enteric bacterial pathogens, specifically Salmonella enterica serovar Typhimurium (ST) and enterohaemorrhagic Escherichia coli (EHEC). By inserting mcra in L. casei, we generated LC-CLA and found the total linoleic acid production by an individual bacterial cell was raised by 21-fold. The adherence ability of LC-CLA on human epithelial cells increased significantly and LC-CLA competitively excluded both ST and EHEC in a mixed-culture condition. Furthermore, LC-CLA significantly altered the physicochemical properties, biofilm formation abilities, interactions with host cells of both ST and EHEC, and triggered anti-inflammatory activities of host cells. These findings offer insights on applying a genetically engineered probiotic to control gut intestinal infections caused by ST and EHEC and prevent foodborne enteric illness in human.

Alternative Growth Promoters Modulate Broiler Gut Microbiome and Enhance Body Weight Gain

Antibiotic growth promoters (AGPs) are frequently used to enhance weight-gain in poultry production. However, there has been increasing concern over the impact of AGP on the emergence of antibiotic resistance in zoonotic bacterial pathogens in the microbial community of the poultry gut. In this study, we adopted mass-spectrophotometric, phylogenetic, and shotgun-metagenomic approaches to evaluate bioactive phenolic extracts (BPE) from blueberry (Vaccinium corymbosum) and blackberry (Rubus fruticosus) pomaces as AGP alternatives in broilers. We conducted two trials with 100 Cobb-500 broiler chicks (in each trial) in four equal groups that were provided water with no supplementation, supplemented with AGP (tylosin, neomycin sulfate, bacitracin, erythromycin, and oxytetracycline), or supplemented with 0.1 g Gallic acid equivalent (GAE)/L or 1.0 g GAE/L (during the last 72 h before euthanasia) of BPE for 6 weeks. When compared with the control group (water only), the chickens supplemented with AGP and 0.1 g GAE/L of BPE gained 9.5 and 5.8% more body weight, respectively. The microbiomes of both the AGP- and BPE-treated chickens had higher Firmicutes to Bacteroidetes ratios. AGP supplementation appeared to be associated with higher relative abundance of bacteriophages and unique cecal resistomes compared with BPE supplementation or control. Functional characterization of cecal microbiomes revealed significant animal-to-animal variation in the relative abundance of genes involved in energy and carbohydrate metabolism. These findings established a baseline upon which mechanisms of plant-based performance enhancers in regulation of animal growth can be investigated. In addition, the data will aid in designing alternate strategies to improve animal growth performance and consequently production.

Eradication and Sensitization of Methicillin Resistant Staphylococcus aureus to Methicillin with Bioactive Extracts of Berry Pomace

The therapeutic roles of phenolic blueberry (Vaccinium corymbosum) and blackberry (Rubus fruticosus) pomace (commercial byproduct) extracts (BPE) and their mechanism of actions were evaluated against methicillin resistant Staphylococcus aureus (MRSA). Five major phenolic acids of BPE, e.g., protocatechuic, p. coumaric, vanillic, caffeic, and gallic acids, as well as crude BPE completely inhibited the growth of vegetative MRSA in vitro while BPE+methicillin significantly reduced MRSA biofilm formation on plastic surface. In addition, BPE restored the effectiveness of methicillin against MRSA by down-regulating the expression of methicillin resistance (mecA) and efflux pump (norA, norB, norC, mdeA, sdrM, and sepA) genes. Antibiogram with broth microdilution method showed that MIC of methicillin reduced from 512 μg/mL to 4 μg/mL when combined with only 200 μg Gallic Acid Equivalent (GAE)/mL of BPE. Significant reduction in MRSA adherence to and invasion into human skin keratinocyte Hek001 cells were also noticed in the presence of BPE. BPE induced anti-apoptosis and anti-autophagy pathways through overexpression of Bcl-2 gene and down-regulation of TRADD and Bax genes (inducers of apoptosis pathway) in Hek001 cells. In summary, novel and sustainable prophylactic therapy can be developed with BPE in combination with currently available antibiotics, especially methicillin, against skin and soft tissue infections with MRSA.