Lactobacillus rhamnosus GG Affects Microbiota and Suppresses Autophagy in the Intestines of Pigs Challenged with Salmonella Infantis

The impact of combined thymol and rosmarinic acid on the intestinal microbiota and barrier function of the piglets challenged by Escherichia coli K88

It has been found that thymol (Thy) and rosmarinic acid (Ros-A) improve the growth performance of piglets and relieve intestinal inflammation in animals. The effects of Thy and Ros-A separately or in combination (Thy × Ros-A) on the intestinal function and health of piglets challenged with Escherichia coli K88 (E. coli K88) were investigated. A total of 30 piglets aged 21 d were assigned to 5 groups (n = 6). The control (Con) and K88 groups piglets received a basal diet, while the Thy, Ros-A, and Thy × Ros-A groups were fed a basal diet supplemented with 500 mg/kg Thy, 500 mg/kg Ros-A, and 250 mg/kg Thy + 250 mg/kg Ros-A, respectively. On the 19th and 20th day, piglets in the K88, Thy, Ros-A, and Thy × Ros-A groups were orally administered 10 mL of phosphate-buffered saline (PBS) containing approximately 1 × 109 CFU/mL of E. coli K88, while the Con group received an equal volume of PBS. The results showed that the Thy × Ros-A treatment reduced the damage to ileal villi induced by the E. coli K88 challenge, leading to longer villi in the ileum (P < 0.05). Thy and Ros-A modulated the composition of the ileal microbiota. Compared to the K88 group, the Thy × Ros-A group had a higher abundance of Lactobacillus and Romboutsia, while Escherichia-Shigella and Desulforvibrio were lower (P < 0.05). Additionally, the Thy × Ros-A group showed elevated levels of gene and protein expressions for zonula occludens-1, occludin, and claudin-1 compared to the K88 group (P < 0.05). In conclusion, combining Thy and Ros-A reduced ileal damage and relieved the inflammation in weaned piglets challenged with E. coli K88 by regulating intestinal microflora and improving barrier function.

Engineered Bacillus subtilis WB600/ZD prevents Salmonella Infantis-induced intestinal inflammation and alters the colon microbiota in a mouse model

Antimicrobial peptides (AMPs) are instrumental in maintaining intestinal homeostasis and have emerged as potential therapeutic candidates for ameliorating intestinal bacterial infections. However, the intrinsic instability associated with the in vivo delivery of AMPs constitutes a substantial impediment to their therapeutic efficacy in treating infections. In this study, we genetically modified Bacillus subtilis (B. subtilis) WB600 to express Zophobas atratus defensin (ZD), an antimicrobial peptide with broad-spectrum activity isolated from Zophobas atratus, for oral administration. This engineered strain effectively protects against Salmonella Infantis (S. Infantis) infection in mice. Pretreatment with WB600/ZD prevented NF-κB pathway activation induced by S. Infantis infection and increased expression of antioxidant and tight junction proteins, thus alleviating the severity of intestinal inflammation in both the jejunum and ileum (P < 0.01). Moreover, WB600/ZD pretreatment facilitated the growth of beneficial bacteria such as Lachnospiraceae, Butyricicoccus, Eubacterium_xylanophilum, and Clostridia_UCG-014 while decreasing the abundance of pathogenic bacteria such as Escherichia-Shigella and Salmonella (P < 0.05). In conclusion, this study underscores the protective effects of WB600/ZD on S. Infantis-induced intestinal inflammation, suggesting that oral delivery of B. subtilis WB600/ZD may be a promising prophylactic strategy for combating bacterial infections in the intestine.

The interplay between probiotics and host autophagy: mechanisms of action and emerging insights

Autophagy, a lysosome-dependent protein degradation mechanism, is a highly conserved catabolic process seen in all eukaryotes. This cell protection system, which is present in all tissues and functions at a basic level, can be up- or downregulated in response to various stresses. A disruption in the natural route of the autophagy process is frequently followed by an interruption in the inherent operation of the body's cells and organs. Probiotics are live bacteria that protect the host through various mechanisms. One of the processes through which probiotics exert their beneficial effects on various cells and tissues is autophagy. Autophagy can assist in maintaining host homeostasis by stimulating the immune system and affecting numerous physiological and pathological responses. In this review, we particularly focus on autophagy impairments occurring in several human illnesses and investigate how probiotics affect the autophagy process under various circumstances.Abbreviation: AD: Alzheimer disease; AKT: AKT serine/threonine kinase; AMPK: 5'AMP-activated protein kinase; ATG: autophagy related; CCl4: carbon tetrachloride; CFS: cell-free supernatant; CMA: chaperone-mediated autophagy; CRC: colorectal cancer; EPS: L. plantarum H31 exopolysaccharide; HD: Huntington disease; HFD: high-fat diet; HPV: human papillomavirus; IFNG/IFN-γ: interferon gamma; IL6: interleukin 6; LGG: L. rhamnosus GG; LPS: lipopolysaccharide; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; NAFLD: non-alcoholic fatty liver disease; NASH: non-alcoholic steatohepatitis; PD: Parkinson disease; Pg3G: pelargonidin-3-O-glucoside; PI3K: phosphoinositide 3-kinase; PolyQ: polyglutamine; ROS: reactive oxygen species; SCFAs: short-chain fatty acids; SLAB51: a novel formulation of lactic acid bacteria and bifidobacteria; Slp: surface layer protein (of acidophilus NCFM); SNCA: synuclein alpha; ULK1: unc-51 like autophagy-activating kinase 1; YB: B. longum subsp. infantis YB0411; YFP: yeast fermentate prebiotic.

Effects of Supplementing Yeast Fermentation Products on Growth Performance, Colonic Metabolism, and Microbiota of Pigs Challenged with Salmonella Typhimurium

Yeast fermentation products (YFPs) are known to contain bioactive compounds, such as nutritional metabolites and cell wall polysaccharides (specifically glucan and mannan), which have been demonstrated to exert positive effects on the growth performance and immunity of livestock and poultry. However, the impact of YFPs on intestinal inflammation and microflora composition in pigs infected with Salmonella typhimurium remains unclear. To investigate this, a total of 18 weaned pigs were divided into three treatment groups: a non-challenged control group (Con), a group challenged with Salmonella typhimurium (ST), and a group challenged with Salmonella typhimurium and supplemented with 0.4% YFP (YFP). The experiment spanned five weeks, encompassing a period of 21 days prior to and 14 days subsequent to the initial Salmonella typhimurium challenge. The findings indicated that the YFP group exhibited an increase in average daily gain (ADG) and a decrease in the feed-gain ratio (F/G) in comparison to the ST group following the Salmonella challenge. Additionally, the YFP group demonstrated a reduction in the levels of inflammatory cytokines in plasma and a decrease in the expression of inflammatory genes in the colon. Treatment with YFP also resulted in improved colon histomorphology, heightened alpha diversity of the gut microbiota, augmented the abundance of butyrate-producing bacteria, and elevated concentrations of short-chain fatty acids (SCFAs). In addition, YFP reprogrammed energy metabolism in colon epithelial cells by blunting glycolysis. Together, dietary YFP supplementation alleviated colon inflammation in weaned pigs challenged with Salmonella typhimurium, and shaped the beneficial microbiota, thereby maintaining gut homeostasis. The results provided evidence supporting the application of yeast fermentation products in livestock production.

Maternal probiotic mixture supplementation optimizes the gut microbiota structure of offspring piglets through the gut-breast axis

Delivery and weaning are major stressful events in sows and piglets, adversely affecting production and growth performance and causing economic losses to swine farms. Probiotics as safe antibiotic alternatives have great potential for use across all stages of livestock farming. Here, 18 pregnant sows from clinical farms randomly were divided into two groups: one fed a basal diet (CON group) and the other fed a basal diet plus a probiotic mixture CBB-mix (containing 1×1012 CFU/g of Lactobacillus johnsonii [CJ21], 1×109 CFU/g of Bacillus subtilis [BS15], and 1×109 CFU/g of Bacillus licheniformis [BL21]), for 20 days before delivery. The effects of maternal CBB-mix supplementation on sow colostrum metabolome and offspring piglets' clinical performance, immune status, and gut microbiota were investigated. Additionally, 177 piglets were randomly divided into 4 groups, including CC group (piglets and sows fed a basal diet, n = 40 from 5 litters), CP group (piglets fed the basal diet plus CBB-mix and sows fed the basal diet, n = 38 from 4 litters), PC group (piglets fed the basal diet and sows fed the basal diet plus CBB-mix, n = 50 from 4 litters), and PP group (both piglets and sows fed the basal diet plus CBB-mix, n = 49 from 5 litters). Among that, CP and PP groups were added CBB-mix in the creep feed from 11 days of age for 18 days to study the direct effects of CBB-mix on the growth performance of piglets. Maternal CBB-mix supplementation improved sow production performance, including litter size at birth and litter weight at birth (P < 0.05). Piglets born from CBB-mix-fed sows exhibited increased litter size at weaning and reduced diarrhea incidence from 1 to 10 days of age (P < 0.05). Additionally, systemic immune status and antioxidant capabilities were improved in both sows and piglets. Maternal CBB-mix supplementation reconstituted the gut microbiota structure and increased the Sobs index and Shannon index of fecal microbiota in both sows and piglets (P < 0.05). The relative abundance of Firmicutes and Clostridium_sensu_stricro_1 in sow feces was decreased after feeding CBB-mix (P < 0.05). In piglets, 10-day-old feces had relatively more Lactobacillus but less Escherichia-Shigella than 1-day-old feces (P < 0.05), indicating that maternal feeding CBB-mix alone affects the gut microbiota community of offspring piglets via the gut-breast axis. Piglets born from CBB-mix-fed sows had continuously decreased the relative abundance of fecal Escherichia-Shigella at 28 days of age (P < 0.05). Consistently, the metabolite profile in sow milk was also changed by CBB-mix. Colostrum metabolome showed that CBB-mix significantly regulated tryptophan metabolism and primary bile acid biosynthesis. Our data demonstrated that maternal CBB-mix supplementation effectively improved the production performance of sows and their offsprings' growth performance. Through the gut-breast axis (interaction between gut microbiota and mammary glands), feeding CBB-mix to sows impacted the gut microbiota of their offspring. This study provides strategy and evidence for maternal probiotic supplementation to improve immune status and gut microbiota homeostasis in response to delivery and weaning.

Role of immunomodulatory probiotics in alleviating bacterial diarrhea in piglets: a systematic review

Diarrhea is a common enteric disease in piglets that leads to high mortality and economic losses in swine production worldwide. Antibiotics are commonly used to prevent or treat diarrhea in piglets. However, irrational antibiotic use contributes to the development of resistance in bacteria and antibiotic residues in animal products, threatening public health, while causing gut microbiota dysbiosis and antibiotic-resistant bacterial infection in piglets. Therefore, the quest for alternative products (such as probiotics, prebiotics, organic acids, enzymes, essential oils, medium-chain fatty acids, zinc, and plant extracts) has recently been clearly emphasized through the increase in regulations regarding antibiotic use in livestock production. These antibiotic alternatives could lower the risk of antibiotic-resistant bacteria and meet consumer demand for antibiotic-free food. Several antibiotic alternatives have been proposed, including immunomodulatory probiotics, as candidates to reduce the need for antimicrobial therapy. Many studies have revealed that probiotics can avert and cure bacterial diarrhea by regulating the gut function and immune system of piglets. In this review, we focus on the major pathogenic bacteria causing piglet diarrhea, the research status of using probiotics to prevent and treat diarrhea, their possible mechanisms, and the safety issues related to the use of probiotics. Supplementation with probiotics is a possible alternative to antibiotics for the prevention or treatment of bacterial diarrhea in piglets. Furthermore, probiotics exert beneficial effects on feed efficiency and growth performance of piglets. Therefore, appropriate selection and strategies for the use of probiotics may have a positive effect on growth performance and also reduce diarrhea in piglets. This review provides useful information on probiotics for researchers, pig nutritionists, and the additive industry to support their use against bacterial diarrhea in piglets.

Lactiplantibacillus argentoratensis AGMB00912 alleviates salmonellosis and modulates gut microbiota in weaned piglets: a pilot study

This study aimed to evaluate the efficacy of Lactiplantibacillus argentoratensis AGMB00912 (LA) in reducing Salmonella Typhimurium infection in weaned piglets. The investigation focused on the influence of LA on the gut microbiota composition, growth performance, and Salmonella fecal shedding. The results indicated that LA supplementation significantly improved average daily gain and reduced the prevalence and severity of diarrhea. Fecal analysis revealed reduced Salmonella shedding in the LA-supplemented group. Furthermore, LA notably altered the composition of the gut microbiota, increasing the levels of beneficial Bacillus and decreasing those of harmful Proteobacteria and Spirochaetes. Histopathological examination showed less intestinal damage in LA-treated piglets than in the controls. The study also observed that LA affected metabolic functions related to carbohydrate, amino acid, and fatty acid metabolism, thereby enhancing gut health and resilience against infection. Short-chain fatty acid concentrations in the feces were higher in the LA group, suggesting improved gut microbial activity. LA supplementation enriched the population of beneficial bacteria, including Streptococcus, Clostridium, and Bifidobacterium, while reducing the number of harmful bacteria, such as Escherichia and Campylobacter. These findings indicate the potential of LA as a probiotic alternative for swine nutrition, offering protective effects to the gut microbiota against Salmonella infection.

The modulatory effect of Lactobacillus gasseri ATCC 33323 on autophagy induced by extracellular vesicles of Helicobacter pylori in gastric epithelial cells in vitro

Helicobacter pylori has been recognized as a true pathogen, which is associated with various gastroduodenal diseases, and gastric adenocarcinoma. The crosstalk between H. pylori virulence factors and host autophagy remains challenging. H. pylori can produce extracellular vesicles (EVs) that contribute to gastric inflammation and malignancy. Some probiotic strains have been documented to modulate cell autophagy process. This study was aimed to investigate the modulatory effect of cell-free supernatant (CFS) obtained from Lactobacillus gasseri ATCC 33323 on autophagy induced by H. pylori-derived EVs. EVs were isolated from two clinical H. pylori strains (BY-1 and OC824), and characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). The viability of AGS cells was assessed after exposure to different concentrations of H. pylori EVs, and L. gasseri CFS. Based on MTT assay and Annexin V-FITC/PI staining, 50 μg/ml of H. pylori EVs and 10 % v/v of L. gasseri CFS were used for further cell treatment experiments. Autophagy was examined using acridin orange (AO) staining, RT-qPCR analysis for autophagy mediators (LC3B, ATG5, ATG12, ATG16L1, BECN1, MTOR, and NOD1), and western blotting for LC3B expression. H. pylori EVs were detected to range in size from 50 to 200 nm. EVs of both H. pylori strains and L. gasseri CFS showed no significant effect on cell viability as compared to untreated cells. H. pylori EVs promoted the development of acidic vesicular organelles and the expression of autophagy-related genes (LC3B, ATG5, ATG12, ATG16L1, BECN1, and NOD1), and decreased the expression of MTOR in AGS cells at 12 and 24 h time periods. In addition, the production of LC3B was increased following 12 h of treatment in AGS cells. In contrast, L. gasseri CFS effectively inhibited EVs-induced autophagy, as evidenced by reduced acidic vesicular organelle formation and modulation of autophagy markers. Our study indicated that L. gasseri CFS can effectively suppress H. pylori EV-induced autophagy in AGS cells. Further investigations are required to decipher the mechanism of action L. gasseri CFS and its metabolites on autophagy inhibition induced by H. pylori.

Comparative Analysis of the Pre-Parturition and Post-Parturition Genital Tract Microbiota in Plateau Bangor Sewa Sheep

(1) Background: Bangor Sewa sheep are an economically significant livestock species on the plateau. The roles of microbiota in reproduction are complex and critical for animal health. But little is known currently about the microbiome of plateau Bangor Sewa sheep. The purpose of this study was to discover the changes in the genital tract microbiota of pre- and post-partum Bangor Sewa sheep. (2) Methods: Samples from the birth canal were obtained for 16S rRNA sequencing, three days before and after delivery, respectively. (3) Results: The results showed that there was a noticeable difference in three phyla and 74 genera between the pre- and post-parturition groups in the microbiota of Bangor Sewa sheep. The changes included a decrease in the abundance of genera related to health (unclassified_Cellulomonadaceae, Cellulomonas, Fibrobacti, Flavobacterium, Eubacterium_ventriosum_group, Acetitomaculum, Aeromicrobium, Dietzia, Romboutsia, Ruminococcus, etc.) and an increased abundance of negatively related genera (Nocardioides, unclassified_Clostridia, Sphingobacteriaceae, unclassified_Ruminococcaceae, Prevotellaceae_UCG_004, Micromonospora, Streptococcus, Facklamia, Bosea, etc.) spp. (4) Conclusions: Microbes can serve as indicators of the physical state of Bangor Sewa sheep. These findings laid the foundation for deciphering the effects of microbial changes during birth on the reproductive health of plateau Bangor Sewa sheep.

Biosynthesized Silver Nanoparticles Derived from Probiotic Lactobacillus rhamnosus (AgNPs-LR) Targeting Biofilm Formation and Quorum Sensing-Mediated Virulence Factors

In recent years, bacterial pathogens have developed resistance to antimicrobial agents that have created a global threat to human health and environment. As a novel approach to combating antimicrobial resistance (AMR), targeting bacteria's virulent traits that can be explained by quorum sensing (QS) is considered to be one of the most promising approaches. In the present study, biologically synthesized silver nanoparticles derived from Lactobacillus rhamnosus (AgNPs-LR) were tested against three Gram-negative bacteria to determine whether they inhibited the formation of biofilms and triggered the virulence factors controlled by QS. In C. violaceum and S. marcescens, a remarkable inhibition (>70%) of QS-mediated violacein and prodigiosin production was recorded, respectively. A dose-dependent decrease in virulence factors of P. aeruginosa (pyocyanin, pyoverdine, LasA protease, LasB elastase and rhamnolipid production) was also observed with AgNPs-LR. The biofilm development was reduced by 72.56%, 61.70%, and 64.66% at highest sub-MIC for C. violaceum, S. marcescens and P. aeruginosa, respectively. Observations on glass surfaces have shown remarkable reductions in biofilm formation, with less aggregation of bacteria and a reduced amount of extra polymeric materials being formed from the bacteria. Moreover, swimming motility and exopolysaccharides (EPS) was also found to reduce in the presence of AgNPs-LR. Therefore, these results clearly demonstrate that AgNPs-LR is highly effective in inhibiting the development of biofilms and the QS-mediated virulent traits of Gram-negative bacteria. In the future, AgNPs-LR may be used as an alternative to conventional antibiotics for the treatment of bacterial infections after careful evaluation in animal models, especially for the development of topical antimicrobial agents.

Lacticaseibacillus rhamnosus Strain GG (LGG) Regulate Gut Microbial Metabolites, an In Vitro Study Using Three Mature Human Gut Microbial Cultures in a Simulator of Human Intestinal Microbial Ecosystem (SHIME)

In the present research, we investigated changes in the gut metabolome that occurred in response to the administration of the Laticaseibacillus rhamnosus strain GG (LGG). The probiotics were added to the ascending colon region of mature microbial communities established in a human intestinal microbial ecosystem simulator. Shotgun metagenomic sequencing and metabolome analysis suggested that the changes in microbial community composition corresponded with changes to metabolic output, and we can infer linkages between some metabolites and microorganisms. The in vitro method permits a spatially-resolved view of metabolic transformations under human physiological conditions. By this method, we found that tryptophan and tyrosine were mainly produced in the ascending colon region, while their derivatives were detected in the transverse and descending regions, revealing sequential amino acid metabolic pathways along with the colonic tract. The addition of LGG appeared to promote the production of indole propionic acid, which is positively associated with human health. Furthermore, the microbial community responsible for the production of indole propionic acid may be broader than is currently known.

Lactobacillus plantarum Metabolites Elicit Anticancer Effects by Inhibiting Autophagy-Related Responses

Lactobacillus plantarum (L. plantarum) is a probiotic that has emerged as novel therapeutic agents for managing various diseases, such as cancer, atopic dermatitis, inflammatory bowel disease, and infections. In this study, we investigated the potential mechanisms underlying the anticancer effect of the metabolites of L. plantarum. We cultured L. plantarum cells to obtain their metabolites, created several dilutions, and used these solutions to treat human colonic Caco-2 cells. Our results showed a 10% dilution of L. plantarum metabolites decreased cell viability and reduced the expression of autophagy-related proteins. Moreover, we found co-treatment with L. plantarum metabolites and chloroquine, a known autophagy inhibitor, had a synergistic effect on cytotoxicity and downregulation of autophagy-related protein expression. In conclusion, we showed the metabolites from the probiotic, L. plantarum, work synergistically with chloroquine in killing Caco-2 cells and downregulating the expression of autophagy-related proteins, suggesting the involvement of autophagy, rather than apoptosis, in their cytotoxic effect. Hence, this study provides new insights into new therapeutic methods via inhibiting autophagy.

In Vitro and In Vivo Evaluation of Lacticaseibacillus rhamnosus GG and Bifidobacterium lactis Bb12 Against Avian Pathogenic Escherichia coli and Identification of Novel Probiotic-Derived Bioactive Peptides

Avian pathogenic E. coli (APEC), an extra-intestinal pathogenic E. coli (ExPEC), causes colibacillosis in poultry and is also a potential foodborne zoonotic pathogen. Currently, APEC infections in poultry are controlled by antibiotic medication; however, the emergence of multi-drug-resistant APEC strains and increased restrictions on the use of antibiotics in food-producing animals necessitate the development of new antibiotic alternative therapies. Here, we tested the anti-APEC activity of multiple commensal and probiotic bacteria in an agar-well diffusion assay and identified Lacticaseibacillus rhamnosus GG and Bifidobacterium lactis Bb12 producing strong zone of inhibition against APEC. In co-culture assay, L. rhamnosus GG and B. lactis Bb12 completely inhibited the APEC growth by 24 h. Further investigation revealed that antibacterial product(s) in the culture supernatants of L. rhamnosus GG and B. lactis Bb12 were responsible for the anti-APEC activity. The analysis of culture supernatants using LC-MS/MS identified multiple novel bioactive peptides (VQAAQAGDTKPIEV, AFDNTDTSLDSTFKSA, VTDTSGKAGTTKISNV, and AESSDTNLVNAKAA) in addition to the production of lactic acid. The oral administration (10⁸ CFU/chicken) of L. rhamnosus GG significantly (P < 0.001) reduced the colonization (~ 1.6 logs) of APEC in the cecum of chickens. Cecal microbiota analysis revealed that L. rhamnosus GG moderated the APEC-induced alterations of the microbial community in the cecum of chickens. Further, L. rhamnosus GG decreased (P < 0.05) the abundance of phylum Proteobacteria, particularly those belonging to Enterobacteriaceae (Escherichia-Shigella) family. These studies indicate that L. rhamnosus GG is a promising probiotic to control APEC infections in chickens. Further studies are needed to optimize the delivery of L. rhamnosus GG in feed or water and in conditions simulating the field to facilitate its development for commercial applications.

Lactobacillus rhamnosus and Staphylococcus epidermidis in gut microbiota: in vitro antimicrobial resistance

The gastrointestinal tract is one of the most complex microbiological niches containing beneficial and non-pathogenic bacterial strains of which some may evolve into virulent under specific conditions. Lactobacillus rhamnosus GG is of the most known beneficial species with an ability to protect the intestine as opposed to Staphylococcus epidermidis 444 which causes serious health risks due to its high antimicrobial resistance. This study investigates first the survival and coexistence ability of L. rhamnosus GG, and S. epidermidis 444 at different pH levels. Subsequently, lysozyme's antimicrobial and antibiofilm effect on these two strains was elucidated before adding different concentrations of oxytetracycline hydrochloride antibiotic. Results showed that 50% inhibition of L. rhamnosus GG, S. epidermidis 444, and a co-culture of these planktonic strains were obtained respectively at a lysozyme concentration of 30, 18, and 26 mg/mL after the addition of ethylenediamine tetra-acetic acid (EDTA). At a pH of 7.5, mixing lysozyme (at IC₅₀) and EDTA with oxytetracycline hydrochloride (700 μg/mL) showed an additional bactericidal effect as compared to its known bacteriostatic effect. Similarly, the addition of lysozyme to the antibiotic further increased the biofilm eradication of S. epidermidis 444 and L. rhamnosus GG where a maximal eradication of 70% was reached. Therefore, the potential development of new drugs based on adding a lysozyme-EDTA mixture to different types of antibiotics may be highly promising.

Anti-cancer activity of human gastrointestinal bacteria

Malignant neoplasm is one of the most incurable diseases among inflammatory diseases. Researchers have been studying for decades to win over this lethal disease and provide the light of hope to humankind. The gastrointestinal bacteria of human hold a complex ecosystem and maintain homeostasis. One hundred trillion microbes are residing in the gastrointestinal tract of human. Disturbances in the microbiota of human's gastrointestinal tract can create immune response against inflammation and also can develop diseases, including cancer. The bacteria of the gastrointestinal tract of human can secrete a variety of metabolites and bioproducts which aid in the preservation of homeostasis in the host and gut. During pathogenic dysbiosis, on the other hand, numerous microbiota subpopulations may increase and create excessive levels of toxins, which can cause inflammation and cancer. Furthermore, the immune system of host and the epithelium cell can be influenced by gut microbiota. Probiotics, which are bacteria that live in the gut, have been protected against tumor formation. Probiotics are now studied to see if they can help fight dysbiosis in cancer patients undergoing chemotherapy or radiotherapy because of their capacity to maintain gut homeostasis. Countless numbers of gut bacteria have demonstrated anti-cancer efficiency in cancer treatment, prevention, and boosting the efficiency of immunotherapy. The review article has briefly explained the anti-cancer immunity of gut microbes and their application in treating a variety of cancer. This review paper also highlights the pre-clinical studies of probiotics against cancer and the completed and ongoing clinical trials on cancers with the two most common and highly effective probiotics Lactobacillus and Bacillus spp.

Lactobacillusjohnsonii L531 Protects against Salmonella Infantis-Induced Intestinal Damage by Regulating the NOD Activation, Endoplasmic Reticulum Stress, and Autophagy

Salmonella enterica serovar Infantis (S. Infantis) is an intracellular bacterial pathogen. It is prevalent but resistant to antibiotics. Therefore, the therapeutic effect of antibiotics on Salmonella infection is limited. In this study, we used the piglet diarrhea model and the Caco2 cell model to explore the mechanism of probiotic Lactobacillus johnsonii L531 (L. johnsonii L531) against S. Infantis infection. L. johnsonii L531 attenuated S. Infantis-induced intestinal structural and cellular ultrastructural damage. The expression of NOD pathway-related proteins (NOD1/2, RIP2), autophagy-related key proteins (ATG16L1, IRGM), and endoplasmic reticulum (ER) stress markers (GRP78, IRE1) were increased after S. Infantis infection. Notably, L. johnsonii L531 pretreatment not only inhibited the activation of the above signaling pathways but also played an anti-S. Infantis infection role in accelerating autophagic degradation. However, RIP2 knockdown did not interfere with ER stress and the activation of autophagy induced by S. Infantis in Caco2 cells. Our data suggest that L. johnsonii L531 pretreatment alleviates the intestinal damage caused by S. Infantis by inhibiting NOD activation and regulating ER stress, as well as promoting autophagic degradation.

Complete Genome Sequence of Lactobacillus salivarius AR809, a Probiotic Strain with Oropharyngeal Tract Resistance and Adhesion to the Oral Epithelial Cells

Lactobacillus salivarius AR809 was isolated from a healthy adult oral cavity with multiple probiotic properties, such as high antimicrobial activity, adhesion to the oral epithelium, resistance to acidic pH, bile, lysozyme, and H₂O₂. In this study, to investigate the genetic basis on probiotic potential and identify the functional genes in the strain, the complete genome of strain AR809 was sequenced by Illumina and PacBio platforms. Then comparative genome analysis on 11 strains of Lactobacillus salivarius was performed. The complete genome of AR809 consisted of a circular 1,747,224 bp chromosome with 33.00% GC content and four circular plasmids [pA (247,948 bp), pB (27,292 bp), pC (3349 bp), and pD (2898 bp), respectively]. From among the 1866 protein-coding genes, 130 carbohydrate metabolism-related genes, 18 bacteriocin biosynthesis-related genes, 74 environmental stress-related genes, and a series of adhesion-related genes were identified via clusters of orthologous genes, Koyto Encyclopedia of Genes and Genomes, and carbohydrate-active enzymes annotation. The comparative genome analysis indicated that genomic homology between AR809 and CICC23174 was the highest. In conclusion, the present work provided valuable insights into the gene's function prediction and understanding the genetic basis on adapting to host oropharyngeal-gastrointestinal tract in strain AR809.

Limosilactobacillus reuteri SLZX19-12 Protects the Colon from Infection by Enhancing Stability of the Gut Microbiota and Barrier Integrity and Reducing Inflammation

Limosilactobacillus reuteri plays an important role in regulating intestinal functions and maintaining barrier integrity in animals. In this study, Limosilactobacillus reuteri strain SLZX19-12 was isolated from the fecal microbiota of Tibetan pigs, and it was found that this strain is sensitive to common antibiotics and has strong resistance to stress. Upon being administered by gavage at different doses, including low, medium, and high doses, for 14 days, Limosilactobacillus reuteri SLZX19-12 may enhance the intestinal barrier. After administration of a high dose of SLZX19-12, mice were challenged with Salmonella enterica serovar Typhimurium SL1344. Infection with Salmonella Typhimurium SL1344 led to disordered colonic microbiotas, colonic inflammation through the S100A8/S100A9-NF-κB pathway and potential apoptosis, and translocation of pathogens to parenteral visceral organs in mice. However, the mice pretreated with Limosilactobacillus reuteri SLZX19-12 showed lower loads of Salmonella in visceral organs, less colonic inflammation, and higher barrier integrity. More importantly, the administration of strain SLZX19-12 resulted in a more stable microbiota structure of the colon, in which the abundance of Alloprevotella was greatly enhanced. Therefore, this study suggests that Limosilactobacillus reuteri SLZX19-12 can protect the colon from infection by enhancing the stability of gut microbiota and barrier integrity and reducing inflammation. IMPORTANCE The use of antibiotics to treat bacterial infections leads to a series of side effects. As an alternative method, the biocontrol strategy, which uses probiotics to suppress pathogens, is considered a potential way to deal with bacterial infections in gut. However, there are few probiotics that are currently safe and can protect against infection. In this study, Limosilactobacillus reuteri strain SLZX19-12 was obtained from Tibetan pigs, which have higher resistance to infection. This strain is sensitive to conventional antibiotics, secretes a wide spectrum of enzymes, and also promotes the intestinal barrier function in mice. In addition, Limosilactobacillus reuteri SLZX19-12 can promote the stability of the gut microbiota to avoid or alleviate the occurrence or development of foodborne infections.

Testosterone Augments Propagation of Toxoplasma gondii in Glioblastoma Cells In Vitro

PURPOSE

Toxoplasmosis can induce various hormonal and behavioral alterations in humans and rodents. Previous studies revealed alterations of sex hormones; especially testosterone, in infected humans and rodents, but little is known about the effects of sex hormones on the propagation of T. gondii. Hence, we aimed to investigate whether testosterone and progesterone influence on T. gondii propagation in neural cells.

METHODS

The glioblastoma cells (U-87MG) were treated with different concentrations of testosterone and progesterone and the infection was done by tachyzoites of the RH strain of T. gondii. The number of infected cells, viability of T. gondii-infected cells, and parasite burden were measured by direct counting under a light microscope, MTT assay, and quantitative real-time PCR (qPCR), respectively.

RESULTS

The results showed that testosterone at concentrations of 100 and 250 nM significantly increased the number of infected cells and parasite burden 24 and 48 h post-treatment compared to untreated controls. Progesterone had no significant effects in the same manner.

CONCLUSION

The results indicated that testosterone could augment the propagation of T. gondii in in vitro.

Dynamics of Changes in the Gut Microbiota of Healthy Mice Fed with Lactic Acid Bacteria and Bifidobacteria

Probiotics are living microorganisms that provide numerous health benefits for their host. Probiotics have various effects on the body; for example, they change gut microbiota, improve the integrity of the epithelial barrier and have anti-inflammatory effects. The use of probiotic supplements that are based on lactic acid bacteria and bifidobacteria is one of the approaches that are used to balance gut microflora. In our study, we evaluated the effects of supplements, which were based on members of the Lactobacillaceae family and bifidobacteria, on the gut microbiome of healthy mice using the 16S rRNA sequencing method. The data that were obtained demonstrated that when mice received the probiotic supplements, statistically significant changes occurred in the composition of the microbiome at the phylum level, which were characterized by an increase in the number of Actinobacteriota, Bacteroidota, Verrucomicrobia and Proteobacteria, all of which have potentially positive effects on health. At the generic level, a decrease in the abundance of members of the Nocardioides, Helicobacter and Mucispirillum genus, which are involved in inflammatory processes, was observed for the group of mice that was fed with lactic acid bacteria. For the group of mice that was fed with bifidobacteria, a decrease was seen in the number of members of the Tyzzerella and Akkermansia genus. The results of our study contribute to the understanding of changes in the gut microbiota of healthy mice under the influence of probiotics. It was shown that probiotics that are based on members of the Lactobacillaceae family have a more positive effect on the gut microbiome than probiotics that are based on bifidobacteria.

Lactobacillus rhamnosus GG ameliorates deoxynivalenol-induced kidney oxidative damage and mitochondrial injury in weaned piglets

Deoxynivalenol (DON) is a common mycotoxin that pollutes food crops and adversely affects the health of animals, even humans. Lactobacillus rhamnosus GG (LGG) can alleviate intestinal injury, and anti-inflammatory and antioxidant effects. However, the potential of LGG in alleviating kidney injury induced by DON in piglets remains to be studied. The objective of this study was to investigate the adverse effect of DON on kidney injury and the protective ability of LGG. A total of twenty-seven weaned piglets were divided into three groups: CON group, DON group (3.11 mg kg^-1 feed) and LGG + DON group (LGG powder 1 g kg^-1 + DON 3.15 mg kg^-1 feed). DON increased the MDA content, and decreased antioxidant enzyme activity (GSH-Px) and total antioxidant capacity (P < 0.05). Meanwhile, DON activated the Nrf2 antioxidant pathway. However, LGG supplementation alleviated the damage of DON to the kidney antioxidant system of piglets. Notably, DON significantly reduced the Sirt3 expression (P < 0.05), which was alleviated by LGG addition. The expression of mitochondrial biogenesis related factors such as VDAC1 and Cyt C was up-regulated by DON (P < 0.05), and LGG could improve mitochondrial ultrastructural abnormalities and mitochondrial dysfunction. In addition, LGG mitigated DON-induced mitochondrial fusion inhibition, and prevented DON-mediated mitochondrial autophagy. In conclusion, LGG play a protective role in DON-induced kidney toxicity, and dietary intervention may be a strategy to reduce mycotoxins.

Probiotics: The Next Dietary Strategy against Brain Aging

Owing to their long history of safe use, probiotic microorganisms, typically from the genus Lactobacillus, have long been recognized, especially in traditional and fermented food industries. Although conventionally used for dairy, meat, and vegetable fermentation, the use of probiotics in health foods, supplements, and nutraceuticals has gradually increased. Over the past two decades, the importance of probiotics in improving gut health and immunity as well as alleviating metabolic diseases has been recognized. The new concept of a gut-heart-brain axis has led to the development of various innovations and strategies related to the introduction of probiotics in food and diet. Probiotics influence gut microbiota profiles, inflammation, and disorders and directly impact brain neurotransmitter pathways. As brain health often declines with age, the concept of probiotics being beneficial for the aging brain has also gained much momentum and emphasis in both research and product development. In this review, the concept of the aging brain, different in vivo aging models, and various aging-related benefits of probiotics are discussed.

Probiotic Lacticaseibacillus rhamnosus GG Increased Longevity and Resistance Against Foodborne Pathogens in Caenorhabditis elegans by Regulating MicroRNA miR-34

In this study, we investigated the relation of probiotic activity of Lacticaseibacillus rhamnosus strain GG (LGG) and expression of microRNA to immune response and longevity in Caenorhabditis elegans host model. First, we evaluated the survival rate of C. elegans due to LGG exposure and bacterial colonization in the intestine. Next, the expression of mRNA and miRNA was analyzed in C. elegans exposure to LGG for 24 h using microarray. After exposure to LGG to C. elegans, colonized LGG was observed in the intestines of C. elegans and induced to extend lifespan. Moreover, persistent LGG in the intestine significantly enhanced the resistance of C. elegans exposed to both pathogenic bacteria and prolonged the lifespan of C. elegans. Transcriptome analysis indicated that LGG affected the expression levels of genes related to the innate immune response and upregulated the abundance of genes in multiple pathways of C. elegans, including Wnt signaling, TGF-beta signaling and mitogen-activated protein kinase (MAPK) pathways. In addition, qRT-PCR analysis confirmed that the expression of antibacterial genes was increased by LGG. Moreover, as the expression of microRNA miR-34 and immune-related pathways increased by exposure to LGG, the lifespan of C. elegans increased. However, in the miR-34 mutant C. elegans, the lifespan by LGG did not increase, so it was determined that miR-34 indirectly affects immune-related pathways. There was no significant difference in the expression of PMK-1 for LGG exposure in miR-34 mutants, suggesting that miR-34 may regulate PMK-1. In conclusion, we suggest that exposure of LGG to C. elegans enhances lifespan and resistance to food-borne pathogen infection by stimulating miR-34 and indirectly promoting PMK-1 activity.

Ecological performance of multifunctional pesticide tolerant strains of Mesorhizobium sp. in chickpea with recommended pendimethalin, ready-mix of pendimethalin and imazethpyr, carbendazim and chlorpyrifos application

The present study was designed to screen the Mesorhizobium strains (50) for tolerance with four recommended pesticides in chickpea. In-vitro, robust pesticide tolerant strains were developed in pesticides amended media over several generations. Further, verification of the multifunctional traits of pesticide tolerant mesorhizobia under pesticide stress was conducted in-vitro. Among different pesticides, significantly high tolerance in Mesorhizobium strains was observed with recommended doses of pendimethalin (37%) and ready-mix (36%) followed by chlorpyrifos (31%) and carbendazim (30%), on an overall basis. Based on multifunctional traits, Mesorhizobium strains viz. MR2, MR17 and recommended MR33 were the most promising. Ecological performance of the potential Mesorhizobium strains alone and in dual-inoculation with recommended PGP rhizobacterium strain RB-1 (Pseudomonas argenttinensis JX239745.1) was subsequently analyzed in field following standard pesticide application in PBG-7 and GPF-2 chickpea varieties for two consecutive rabi seasons (2015 and 2016). Dual-inoculant treatments; recommended RB-1 + MR33 (4.1%) and RB-1 + MR2 (3.8%) significantly increased the grain yield over Mesorhizobium alone treatments viz MR33 and MR2, respectively. Grain yield in PBG7 variety was significantly affected (7.3%) by the microbial inoculant treatments over GPF2 variety. Therefore, the potential pesticide tolerant strains MR2 and MR33 can be further explored as compatible dual-inoculants with recommended RB-1 for chickpea under environmentally stressed conditions (pesticide application) at multiple locations. Our approach using robust multifunctional pesticide tolerant Mesorhizobium for bio-augmentation of chickpea might be helpful in the formulation of effective bio-inoculants consortia in establishing successful chickpea-Mesorhizobium symbiosis.

L. reuteri ZJ617 inhibits inflammatory and autophagy signaling pathways in gut-liver axis in piglet induced by lipopolysaccharide

Background

This study investigated the protective effects of L. reuteri ZJ617 on intestinal and liver injury and the underlying mechanisms in modulating inflammatory, autophagy, and apoptosis signaling pathways in a piglet challenged with lipopolysaccharide (LPS).

Methods

Duroc × Landrace × Large White piglets were assigned to 3 groups (n = 6/group): control (CON) and LPS groups received oral phosphate-buffered saline for 2 weeks before intraperitoneal injection (i.p.) of physiological saline or LPS (25 μg/kg body weight), respectively, while the ZJ617 + LPS group was orally inoculated with ZJ617 for 2 weeks before i.p. of LPS. Piglets were sacrificed 4 h after LPS injection to determine intestinal integrity, serum biochemical parameters, inflammatory signaling involved in molecular and liver injury pathways.

Results

Compared with controls, LPS stimulation significantly increased intestinal phosphorylated-p38 MAPK, phosphorylated-ERK and JNK protein levels and decreased IκBα protein expression, while serum LPS, TNF-α, and IL-6 concentrations (P < 0.05) increased. ZJ617 pretreatment significantly countered the effects induced by LPS alone, with the exception of p-JNK protein levels. Compared with controls, LPS stimulation significantly increased LC3, Atg5, and Beclin-1 protein expression (P < 0.05) but decreased ZO-1, claudin-3, and occludin protein expression (P < 0.05) and increased serum DAO and D-xylose levels, effects that were all countered by ZJ617 pretreatment. LPS induced significantly higher hepatic LC3, Atg5, Beclin-1, SOD-2, and Bax protein expression (P < 0.05) and lower hepatic total bile acid (TBA) levels (P < 0.05) compared with controls. ZJ617 pretreatment significantly decreased hepatic Beclin-1, SOD2, and Bax protein expression (P < 0.05) and showed a tendency to decrease hepatic TBA (P = 0.0743) induced by LPS treatment. Pretreatment of ZJ617 before LPS injection induced the production of 5 significant metabolites in the intestinal contents: capric acid, isoleucine 1TMS, glycerol-1-phosphate byproduct, linoleic acid, alanine-alanine (P < 0.05).

Conclusions

These results demonstrated that ZJ617 pretreatment alleviated LPS-induced intestinal tight junction protein destruction, and intestinal and hepatic inflammatory and autophagy signal activation in the piglets.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-021-00624-9.

Lactobacillus rhamnosus GR-1 Prevents Escherichia coli-Induced Apoptosis Through PINK1/Parkin-Mediated Mitophagy in Bovine Mastitis

Escherichia coli is one of the most important pathogens that cause clinical mastitis in dairy cattle worldwide and lead to severe economic losses. Antibiotics are often used to treat this inflammatory disease; however, antimicrobial resistance and environmental pollution cannot be ignored. Probiotic is the best alternative; however, its mechanisms of action to prevent mastitis remain unclear. Moreover, the role of probiotics in regulating mitophagy, a selective autophagy that maintains mitochondrial quality, needs to be explored. E. coli infection induced NOD-like receptor family member pyrin domain-containing protein 3 (NLRP3) inflammasome assembly, Caspase-1 activation, and apoptosis in MAC-T cells. Infection also resulted in mitochondrial damage and subsequent increase in reactive oxygen species (ROS) production. Moreover, inhibition of ROS release by scavenger N-acetyl-L-cysteine (NAC) abrogated the importance of ROS in NLRP3 assembly and apoptosis in MAC-T cells. Pretreatment with Lactobacillus rhamnosus GR-1 (LGR-1), a probiotic, alleviated E. coli-induced NLRP3 inflammasome activation and apoptosis via ROS inhibition. Besides, E. coli infection inhibited mitophagy while LGR-1 pretreatment augmented PINK1/Parkin–mediated mitophagy activation, which further blocked ROS generation. To explore the effect of LGR-1 in vivo, a mouse mastitis model was established. The results showed that LGR-1 pretreatment had preventive and protective effects on E. coli induced mastitis, and could reduce cytokines levels such as IL-1β and TNF-α. In accordance with the results in vitro, E. coli can inhibit mitophagy and activate NLRP3 inflammasome and apoptosis, while LGR-1 can weaken the effect of E. coli. Taken together, our data indicated that LGR-1 pretreatment induced PINK1/Parkin-mediated mitophagy that eliminated damaged mitochondria and reduced ROS production and NLRP3 inflammasome activation, which subsequently decreased E. coli-induced apoptosis. To conclude, our study suggests that therapeutic strategies aiming at the upregulation of mitophagy under E. coli-induced mastitis may preserve mitochondrial function and provide theoretical support for the application of probiotics in bovine mastitis.

Effects of Lactococcus lactis on the Intestinal Functions in Weaning Piglets

Post-weaning diarrhea of piglets is associated with gut microbiota dysbiosis and intestinal pathogen infection. Recent studies have shown that Lactococcus lactis (L.lactis) could help suppress pathogen infection. This study aimed to investigate the effects of L.lactis on various factors related to growth and immunity in weaning piglets. The results showed that L.lactis improved the growth performance, regulated the amino acid profile (for example, increasing serum tryptophan and ileal mucosal cystine) and the intestinal GABAergic system (including inhibiting ileal gene expression of SLC6A13, GABAAρ1, π, θ, and γ1, and promoting ileal GABAAα5 expression). L.lactis also modulated intestinal immunity by promoting jejunal interleukin 17, 18, 22, ileal toll-like receptor 2, 5, 6, and myeloid differentiation primary response protein 88 gene expression while inhibiting jejunal interferon-γ and ileal interleukin 22 expressions. L.lactis highly affected the intestinal microbiota by improving the beta diversity of gut microbiota and the relative abundance of Halomonas and Shewanella. In conclusion, L.lactis improved the growth performance and regulated amino acid profiles, intestinal immunity and microbiota in weaning piglets.

Comparative Effect of Fertilization Practices on Soil Microbial Diversity and Activity: An Overview

Continuously increasing human population demands increased food production, which needs greater fertilizer's input in agricultural lands to enhance crop yield. In this respect, different fertilization practices gained acceptance among farmers. We reviewed effect of three main fertilization practices (Conventional-, Organic-, and Bio-fertilization) on soil microbial diversity, activity, and community composition. Studies reported that over application of inorganic fertilizers decline soil pH, change soil osmolarity, cause soil degradation, disturb taxonomic diversity and metabolism of soil microbes and cause accumulation of extra nutrients into the soil such as phosphorous (P) accumulation. On the contrary, organic fertilizers increase organic carbon (OC) input in the soil, which strongly encourage growth of heterotrophic microbes. Organic fertilizer vermicompost application provides readily available nutrients to both plants as well as microbes and encourage overall microbial number in the soil. Most recently, role of beneficial bacteria in long-term sustainable agriculture attracted attention of scientists towards their use as biofertilizer in the soil. Studies documented favorable effect of biofertilization on microbial Shannon, Chao and ACE diversity indices in the soil. It is concluded from intensive review of literature that all the three fertilization practices have their own way to benefit the soil with nutrients, but biofertilization provides long-term sustainability to crop lands. When it is used in integration with organic fertilizers, it makes the soil best for microbial growth and activity and increase microbial diversity, providing nutrients to soil for a longer time, thus improving crop productivity.

Transcriptome Analysis Identifies Strategies Targeting Immune Response-Related Pathways to Control Enterotoxigenic Escherichia coli Infection in Porcine Intestinal Epithelial Cells

Enterotoxigenic Escherichia coli (ETEC) is an important cause of post-weaning diarrhea (PWD) worldwide, resulting in huge economic losses to the swine industry worldwide. In this study, to understand the pathogenesis, the transcriptomic analysis was performed to explore the biological processes (BP) in porcine intestinal epithelial J2 cells infected with an emerging ETEC strain isolated from weaned pigs with diarrhea. Under the criteria of |fold change| (FC) ≥ 2 and P < 0.05 with false discovery rate < 0.05, a total of 131 referenced and 19 novel differentially expressed genes (DEGs) were identified after ETEC infection, including 96 upregulated DEGs and 54 downregulated DEGs. The Gene Ontology (GO) analysis of DEGs showed that ETEC evoked BP specifically involved in response to lipopolysaccharide (LPS) and negative regulation of intracellular signal transduction. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that immune response-related pathways were mainly enriched in J2 cells after ETEC infection, in which tumor necrosis factor (TNF), interleukin 17, and mitogen-activated protein kinase (MAPK) signaling pathways possessed the highest rich factor, followed by nucleotide-binding and oligomerization domain-like receptor (NLRs), C-type lectin receptor (CLR), cytokine–cytokine receptor interaction, and Toll-like receptor (TLR), and nuclear factor kappa-B (NF-κB) signaling pathways. Furthermore, 30 of 131 referenced DEGs, especially the nuclear transcription factor AP-1 and NF-κB, participate in the immune response to infection through an integral signal cascade and can be target molecules for prevention and control of enteric ETEC infection by probiotic Lactobacillus reuteri. Our data provide a comprehensive insight into the immune response of porcine intestinal epithelial cells (IECs) to ETEC infection and advance the identification of targets for prevention and control of ETEC-related PWD.

Dietary oregano essential oil supplementation improves intestinal functions and alters gut microbiota in late-phase laying hens

BACKGROUND

Dietary essential oil (EO) supplementation can exert favorable effects on gut health in broilers. However, it is unknown whether EO could improve intestinal functions, consequently beneficial for egg performance and quality in late-phase laying hens. This study was aimed to investigate the potential effects of EO on production performance, egg quality, intestinal health and ileal microbiota of hens in the late phase of production. A total of 288 60-week-old Hy-line Brown laying hens were randomly divided into 4 groups and fed a basal diet (control) or basal diets supplemented with oregano EO at 100, 200 and 400 mg/kg (EO100, EO200 and EO400).

RESULTS

Dietary EO supplementation resulted in a quadratic decrease (P < 0.05) in feed conversion ratio with lower (P < 0.05) feed conversion ratio in EO200 group than the control during weeks 9-12 and 1-12 of the trial. Compared to the control, EO addition resulted in higher (P < 0.05) eggshell thickness at the end of week. 4, 8 and 12 and higher (P < 0.05) chymotrypsin activity. There was a quadratic elevation (P < 0.05) in ileal chymotrypsin and lipase activity, along with a linear increase in villus height to crypt depth ratio. Quadratic declines (P < 0.05) in mRNA expression of IL-1β, TNF-α, IFN-γ and TLR-4, concurrent with a linear and quadratic increase (P < 0.05) in ZO-1 expression were identified in the ileum with EO addition. These favorable effects were maximized at medium dosage (200 mg/kg) of EO addition and intestinal microbial composition in the control and EO200 groups were assessed. Dietary EO addition increased (P < 0.05) the abundances of Burkholderiales, Actinobacteria, Bifidobacteriales, Enterococcaceae and Bacillaceae, whereas decreased Shigella abundance in the ileum.

CONCLUSIONS

Dietary EO addition could enhance digestive enzyme activity, improve gut morphology, epithelial barrier functions and modulate mucosal immune status by altering microbial composition, thus favoring feed efficiency and eggshell quality of late-phase laying hens.

Changes in soil ammonia oxidizers and potential nitrification after clear-cutting of boreal forests in China

The Korean pine and broad-leaved mixed forests are the most typical and complete ecosystem among the global boreal forests, with extremely important ecological functions. However, few studies on the changes of soil ammonia oxidizers and potential nitrification after clear-cutting of forests are reported. In this study, in contrast to primary Korean pine forests, nitrate (NO₃^-) was significantly higher in secondary broad-leaved forests, while ammonium (NH₄⁺) was on the contrary. The abundance of ammonia-oxidizing bacteria (AOB) was greatly higher in secondary broad-leaved forests, while levels of ammonia-oxidizing archaea (AOA) were not significantly different between them. The significant differences of community structure of AOA and AOB were observed in different forest types and soil layers. Compared with AOA, community compositions of AOB was more sensitive to forest type. The dominant groups of AOA were Nitrososphaera and Nitrosotalea, and the dominant group of AOB was Nitrosospira, of which Nitrosospira cluster 2 and 4 were functional groups with highly activity. Soil potential nitrification rate (PNR) was higher in secondary broad-leaved forests. Furthermore, PNR and AOB abundance had a significant positive correlation, but no significant correlation with AOA abundance. These results provide insights into the soil nitrogen balance and effects on forest restoration after clear-cutting.

Encapsulated Mixture of Methyl Salicylate and Tributyrin Modulates Intestinal Microbiota and Improves Growth Performance of Weaned Piglets

Tributyrin and essential oils have been used as alternatives to antimicrobials to improve gut health and growth performance in piglets. This study was to evaluate the effects of a dietary supplement with two encapsulated products containing different combinations of tributyrin with oregano or with methyl salicylate on growth performance, serum biochemical parameters related to the physiological status, intestinal microbiota and metabolites of piglets. A total of 108 weaned crossbred piglets (Yorkshire × Landrace, 21 ± 1 d, 8.21 ± 0.04 kg) were randomly divided into three groups. Piglets were fed with one of the following diets for 5 weeks: a basal diet as the control (CON); the control diet supplemented with an encapsulated mixture containing 30% of methyl salicylate and tributyrin at a dosage of 3 kg/t (CMT); and the control diet supplemented with an encapsulated mixture containing 30% of oregano oil and tributyrin at a dosage of 3 kg/t (COT). At the end of the feeding trial, six piglets from each group were slaughtered to collect blood and gut samples for physiological status and gut microbiological analysis. The study found that the CMT group was larger in feed intake (FI) (p < 0.05), average daily gain (ADG) (p = 0.09), total protein (TP), albumin (ALB), glutathione peroxidase (GSH-PX) (p < 0.05), blood total antioxidant capacity (T-AOC) (p < 0.05), and crypt depth in the ileum (p < 0.05) compared with the CON group. The genus abundance of Tissierella and Campylobacter in the CMT group was significantly decreased compared with the CON group. The CMT group also resulted in significantly higher activity in amino acid metabolism and arginine biosynthesis compared with the CON group. The COT group was larger in T-AOC, and the genus abundance of Streptophyta and Chlamydia was significantly increased in the ileum compared with the CON group. Data analysis found a significantly high correlation between the genus abundance of Chlamydia and that of Campylobacter in the ileum. The genus abundance of Campylobacter was also positively correlated with the sorbitol level. In general, the results indicated that the supplementation of both encapsulated mixtures in diet of weaned piglets could improve the animal blood antioxidant capacity. Additionally, the encapsulated mixture of methyl salicylate plus tributyrin improved the growth performance and resulted in certain corresponding changes in nutrient metabolism and in the genus abundance of ileum microbial community.

Short-term intake of Lactiplantibacillus plantarum ZDY2013 fermented milk promotes homoeostasis of gut microbiota under enterotoxigenic Bacillus cereus challenge

Probiotics have long been used as functional starter cultures for fermented foods and are associated with numerous health benefits. Lactiplantibacillus (L.) plantarum ZDY2013 is an acid-tolerant probiotic candidate owning antagonistic properties against the food-borne pathogen Bacillus (B.) cereus and serves as a potent regulator of the gut microbiota. However, whether it retains these properties when used as dietary supplements in functional foods remains unknown. Accordingly, we investigated the ameliorating effects of L. plantarum fermented milk on disease phenotypes triggered by enterotoxigenic B. cereus in mice. The results revealed that administration of 3.0 × 108 cfu pathogenic B. cereus for one week induced damage to intestinal structures and bowel function, accompanied by an imbalance of gut microbiota. However, before or after B. cereus infection, oral administration of L. plantarum fermented milk mitigated losses of body weight and damage in the histological structure of the gastrointestinal tract, restored serum levels of IL-1β and IL-10, and contributed to significant decreases in platelet counts and uric acid levels. Most importantly, it restored the dissimilarity of gut microbiota and the abundance of bacterial taxa (i.e., reduced the abundance of Deferribacteres and Bacilli and increased the abundance of Lactobacillus and Bifidobacterium) without impacting the taxonomic composition. Combining these results, we speculate that enterotoxigenic B. cereus damages the intestinal epithelium and weakens its adherence capacity for the microbe, which is rescued by the supplementation of L. plantarum fermented milk. Overall, our findings revealed that L. plantarum ZDY2013 has the potential to be a fermented starter in functional foods and retains its antagonism against B. cereus pathogenesis.

Lactobacillus rhamnosus GG defense against Salmonella enterica serovar Typhimurium infection through modulation of M1 macrophage polarization

Lactobacillus rhamnosus GG (LGG), a model probiotic strain, plays an important role in immune regulatory activity to prevent and treat intestinal inflammation or diarrhea. However, the effect of the immune modulation of LGG on macrophages to prevent Salmonella infection has not been thoroughly studied. In this study, C57BL/6 mice were pre-administered LGG for 7 days continuously, and then infected with Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium). The results of the in vivo study indicated that LGG could reduce body weight loss, death rate and intestinal inflammatory response caused by S. Typhimurium. LGG also limited S. Typhimurium dissemination to liver and spleen, and thereby protected against infection. In vitro study, we observed that LGG enhanced the phagocytic and bactericidal ability of macrophages and upregulated M1 macrophage characters (e.g. iNOS, NO and IL-12) against S. Typhimurium. In addition, LGG also elevated IL-10 secretion, which was helpful to ameliorate intestinal inflammatory injury caused by S. Typhimurium. In conclusion, LGG could modulate M1 macrophage polarization and offer protective effects against S. Typhimurium infection.

Probiotics Lactobacillus rhamnosus GG ATCC53103 and Lactobacillus plantarum JL01 induce cytokine alterations by the production of TCDA, DHA, and succinic and palmitic acids, and enhance immunity of weaned piglets

Probiotics, including Lactobacillus rhamnosus GG ATCC53103 and Lactobacillus plantarum JL01, can improve growth performance and immunity of piglets, and relieve weaning stress-related immune disorders such as intestinal infections and inflammation. This study aimed to evaluate the ability of co-administration of the probiotics L. rhamnosus GG ATCC53103 and L. plantarum JL01 to stimulate immune responses and improve gut health during the critical weaning period in piglets. Forty-eight weaned piglets were randomly divided into four groups, and fed daily for 28 days either without, or with the two probiotics independently, or in combination. On day 28, we analyzed the cytokine and bacterial changes in intestinal mucosa and the hepatic portal vein blood metabolites of the weaned piglets. Our results showed that combined L. rhamnosus GG ATCC53103 and L. plantarum JL01 significantly increased (p < 0.05) the growth performance and expression of IL-10 and TGF-β1 mRNAs. In contrast, this treatment significantly decreased (p < 0.05) IL-1β mRNA level in the jejunum, ileum, and cecum. Furthermore, the secretion of IL-6 in the cecum, IL-1β in the jejunum, ileum, and cecum, and TNF-α in the jejunum and ileum was significantly decreased (p < 0.05). The relative abundance of Prevotella_9 and Enterococcus in ileum and cecum was significantly increased (p < 0.05). The relative abundance of Ruminococcus_1 and Ruminococcaceae_UCG-005 in cecum was significantly decreased (p < 0.05). Prevotella_9 and Enterococcus may increase the accumulation of (4Z,7Z,10Z,13Z,16Z,19Z)-4,7,10,13,16,19-docosahexaenoic acid (DHA) and tauroursodeoxycholic acid (TCDA) in portal vein blood, while Ruminococcus_1 and Ruminococcaceae_UCG-005 may decrease the accumulation of succinic and palmitic acids. These results indicate that L. rhamnosus GG ATCC53103 and L. plantarum JL01 may regulate cytokine levels by reducing the accumulation of succinic and palmitic acids and increasing the accumulation of TCDA and DHA, thereby enhancing the immunity of weaned piglets.

Mechanism of Lactobacillus rhamnosus in treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a clinically common functional gastrointestinal disease, which affects the quality of life of patients. Therefore, it is of great significance to explore effective treatment methods for IBS. Probiotics can improve the symptoms of IBS patients and their quality of life. Lactobacillus rhamnosus is one of the most studied probiotics and has attracted much attention. . Lactobacillus rhamnosus has been used to treat IBS, and much progress has been made in recent years. Lactobacillus rhamnosus can improve the symptoms of IBS by regulating the imbalance of the intestinal flora, protecting the intestinal barrier function, exerting anti-inflammatory activity, regulating the intestinal immunity, improving visceral hypersensitivity, and inhibiting bacteria. This review aims to elucidate the possible mechanism of Lactobacillus rhamnosus in the treatment of IBS.

Rose virus R, a cytorhabdovirus infecting rose

RNA was extracted from 'Hugh Dickson' rose leaves displaying virus-like symptoms in Maryland, USA. Using high-throughput sequencing, we identified a new virus, tentatively named "rose virus R". This virus has a negative-sense, single-stranded RNA genome and exhibits genomic features of a rhabdovirus, including a genome organization of 3'-N-P-P3-M-G-P6-L-5' and a gene junction region consensus sequence 3'-AUUUAUUUUGACUCUA-5'. Rose virus R is phylogenetically related to cytorhabdoviruses, and the nucleotide and amino acid sequences of rose virus R and related cytorhabdoviruses have diverged considerably, suggesting that rose virus R should be classified as a member of a novel species in the genus Cytorhabdovirus.

Lactobacillus johnsonii L531 Ameliorates Escherichia coli-Induced Cell Damage via Inhibiting NLRP3 Inflammasome Activity and Promoting ATG5/ATG16L1-Mediated Autophagy in Porcine Mammary Epithelial Cells

Escherichia coli (E. coli), a main mastitis-causing pathogen in sows, leads to mammary tissue damage. Here, we explored the effects of Lactobacillus johnsonii L531 on attenuating E. coli-induced inflammatory damage in porcine mammary epithelial cells (PMECs). L. johnsonii L531 pretreatment reduced E. coli adhesion to PMECs by competitive exclusion and the production of inhibitory factors and decreased E. coli-induced destruction of cellular morphology and ultrastructure. E. coli induced activation of NLRP3 inflammasome associated with increased expression of NLRP3, ASC, and cleaved caspase-1, however, L. johnsonii L531 inhibited E. coli-induced activation of NLRP3 inflammasome. Up-regulation of interleukin (Il)-1β, Il-6, Il-8, Il-18, tumor necrosis factor alpha, and chemokine Cxcl2 expression after E. coli infection was attenuated by L. johnsonii L531. E. coli infection inhibited autophagy, whereas L. johnsonii L531 reversed the inhibitory effect of E. coli on autophagy by decreasing the expression of autophagic receptor SQSTM1/p62 and increasing the expression of autophagy-related proteins ATG5, ATG16L1, and light chain 3 protein by Western blotting analysis. Our findings suggest that L. johnsonii L531 pretreatment restricts NLRP3 inflammasome activity and induces autophagy through promoting ATG5/ATG16L1-mediated autophagy, thereby protecting against E. coli-induced inflammation and cell damage in PMECs.

Butyrate-mediated autophagy inhibition limits cytosolic Salmonella Infantis replication in the colon of pigs treated with a mixture of Lactobacillus and Bacillus

Probiotics as an effective and safe strategy for controlling Salmonella infection are much sought after, while autophagy is a central issue in eliminating intracellular pathogens of intestinal epithelial cells. In this study, an animal model of colitis has been developed by infecting weaned pigs orally with a strain of Salmonella Infantis in order to illuminate the potential efficacy of a mixture of Lactobacillus and Bacillus (CBB-MIX) in the resistance to Salmonella infection by regulating butyrate-mediated autophagy. We found that CBB-MIX alleviated S. Infantis-induced colitis and tissue damage. Autophagy markers ATG5, Beclin-1, and the LC3-II/I ratio were significantly enhanced by S. Infantis infection, while treatment with CBB-MIX suppressed S. Infantis-induced autophagy. Additionally, S. Infantis-induced colonic microbial dysbiosis was restored by this treatment, which also preserved the abundance of the butyrate-producing bacteria and the butyrate concentration in the colon. A Caco-2 cell model of S. Infantis infection showed that butyrate had the same effect as the CBB-MIX in restraining S. Infantis-induced autophagy activation. Further, the intracellular S. Infantis load assay indicated that butyrate restricted the replication of cytosolic S. Infantis rather than that in Salmonella-containing vacuoles. Suppression of autophagy by knockdown of ATG5 also attenuated S. Infantis-induced cell injury. Moreover, hyper-replication of cytosolic S. Infantis in Caco-2 cells was significantly decreased when autophagy was inhibited. Our data demonstrated that Salmonella may benefit from autophagy for cytosolic replication and butyrate-mediated autophagy inhibition reduced the intracellular Salmonella load in pigs treated with a probiotic mixture of Lactobacillus and Bacillus.

Disease managing capacities and mechanisms of host effects of lactic acid bacteria

Consumption of lactic acid bacteria (LAB) has been suggested to confer health-promoting effects on the host. However, effects of LABs have been reported to be species- and strain-specific and the mechanisms involved are subjects of discussion. Here, the possible mechanisms by which LABs induce antipathogenic, gut barrier enhancing and immune modulating effects in consumers are reviewed. Specific strains for which it has been proven that health is improved by these mechanisms are discussed. However, most strains probably act via several or combinations of mechanisms depending on which effector molecules they express. Current insight is that these effector molecules are either present on the cell wall of LAB or are excreted. These molecules are reviewed as well as the ligand binding receptors in the host. Also postbiotics are discussed. Finally, we provide an overview of the efficacy of LABs in combating infections caused by Helicobacter pylori, Salmonella, Escherichia coli, Streptococcus pneumoniae, and influenza virus, in controlling gut inflammatory diseases, in managing allergic disorders, and in alleviating cancer.

Anti-inflammatory effects of Lactobacillus johnsonii L531 in a pig model of Salmonella Infantis infection involves modulation of CCR6+ T cell responses and ER stress

Probiotic pretreatment is an effective non-antibiotic strategy for preventing or controlling Salmonella infections. We found that Lactobacillus johnsonii L531, isolated from the colon of a clinically healthy weaned piglet, effectively prevented infection with Salmonella enterica serovar Infantis in a pig model. Newly weaned piglets were intragastrically administered Lactobacillus johnsonii L531 at 1.0 × 10¹⁰ CFU/day for 1 week before S. Infantis challenge. Pretreatment with L. johnsonii L531 lessened the severity of diarrhea and ileal inflammation in S. Infantis-infected piglets. Lactobacilli were more abundant in the ileum than jejunum after L. johnsonii L531 pretreatment. Treatment with L. johnsonii L531 reduced the abundance of total bacteria in the ileal mucosa and the production of lipocalin 2 in the jejunum of piglets challenged with Salmonella. Both intestinal morphology and transmission electron microscopy results indicated that L. johnsonii L531 alleviated intestinal tissue damage following S. Infantis challenge, especially in the villus and endoplasmic reticulum (ER). ER stress induced by S. Infantis was attenuated by L. johnsonii L531 treatment. The number of CD4^- CCR6⁺ T cells decreased following S. Infantis challenge, but the percentage of CCR6^- IFNγ⁺ T cells in peripheral blood increased. In intestinal mesenteric lymph nodes, S. Infantis increased the proportion of CCR6⁺ IFNγ⁺ T cells, whereas L. johnsonii L531 induced an increase in the proportion of CD4⁺ CCR6⁺ T cells in response to S. Infantis infection. Our data thus suggest that L. johnsonii L531 contributes to the maintenance of intestinal homeostasis by modulating T-cell responses and ER stress.

Lactobacillus johnsonii L531 ameliorates enteritis via elimination of damaged mitochondria and suppression of SQSTM1-dependent mitophagy in a Salmonella infantis model of piglet diarrhea

Newly weaned piglets challenged with Salmonella infantis were particularly susceptible, whereas oral preadministration of Lactobacillus johnsonii L531 alleviated enteritis and promoted intestinal secretory IgA production. Salmonella infantis-induced activation of NLRC4 and NLRP3 inflammasomes and (nuclear factor kappa B) NF-κB signaling in the small intestine was also inhibited by L. johnsonii L531 pretreatment, thus limiting inflammation. An IPEC-J2 cell model of S. infantis infection yielded similar results. Salmonella infantis infection also resulted in mitochondrial damage and impaired mitophagy in the ileum and IPEC-J2 cells, as demonstrated by immunofluorescence colocalization of mitochondria with microtubule-binding protein light chain 3 (LC3) and high expression of autophagy-related proteins PTEN-induced putative kinase 1 (PINK1), sequestosome 1 (SQSTM1/p62), optineurin (OPTN), and LC3 by Western blotting analysis. However, L. johnsonii L531 pretreatment reduced both the extent of mitochondrial damage and autophagy-related protein expression. Our findings suggest that the amelioration of S. infantis-associated enteritis by L. johnsonii L531 is associated with regulation of NLRC4 and NLRP3 inflammasomes and NF-κB signaling pathway activation and suppression of mitochondrial damage. Amelioration of impaired mitophagy by L. johnsonii L531 could involve eliminating damaged mitochondria and regulating S. infantis-induced activation of the NF-κB-SQSTM1mitophagy signaling pathway in host cells to prevent the further mitochondrial damage and S. infantis dissemination.

Lactobacillus reuteri ZJ617 Culture Supernatant Attenuates Acute Liver Injury Induced in Mice by Lipopolysaccharide

BACKGROUND

Lactobacillus rhamnosus GG culture supernatant (LGGs) promotes intestinal integrity and ameliorates acute liver injury induced by alcohol in mice.

OBJECTIVES

The aim of this study was to investigate the protective effects and molecular mechanisms of Lactobacillus reuteri ZJ617 culture supernatant (ZJ617s) on acute liver injury induced by lipopolysaccharide (LPS) in mice.

METHODS

Male C57BL/6 mice (20 ± 2 g, 8 wk old) were randomly divided into 4 groups (6 mice/group): oral inoculation with phosphate-buffered saline (control), intraperitoneal injection of LPS (10 mg/kg body weight) (LPS), oral inoculation with ZJ617s 2 wk before intraperitoneal injection of LPS (ZJ617s + LPS), or oral inoculation with LGGs 2 wk before intraperitoneal injection of LPS (LGGs + LPS). Systemic inflammation, intestinal integrity, biomarkers of hepatic function, autophagy, and apoptosis signals in the liver were determined.

RESULTS

Twenty-four hours after LPS injection, the activities of serum alanine transaminase and aspartate transaminase were 32.2% and 30.3% lower in the ZJ617s + LPS group compared with the LPS group, respectively (P < 0.05). The ZJ617s + LPS group exhibited higher intestinal expression of claudin 3 (62.5%), occludin (60.1%), and zonula occludens 1 (60.5%) compared with the LPS group (P < 0.05). The concentrations of hepatic interleukin-6 and tumor necrosis factor-α were 21.4% and 27.3% lower in the ZJ617s + LPS group compared with the LPS group, respectively (P < 0.05). However, the concentration of interleukin-10 was 22.2% higher in the ZJ617s + LPS group. LPS increased the expression of Toll-like receptor 4 (TLR4; by 50.5%), phosphorylation p38 mitogen-activated protein kinase (p38MAPK; by 57.1%), extracellular signal-regulated kinase (by 77.8%), c-Jun N-terminal kinase (by 42.9%), and nuclear factor-κB (NF-κB; by 36.0%) compared with the control group. Supplementation with ZJ617s or LGGs ameliorated these effects (P < 0.05). Moreover, the hepatic expression of active caspase-3 and microtubule-associated protein 1 light chain 3 II was 23.8% and 28.6% lower in the ZJ617s + LPS group compared with the LPS group, respectively (P < 0.05).

CONCLUSIONS

ZJ617s exerts beneficial effects on the mouse liver through suppression of hepatic TLR4/MAPK/NF-κB activation, apoptosis, and autophagy. This trial was registered at Zhejiang University (http://www.lac.zju.edu.cn) as NO.ZJU20170529.

Probiotic Bacillus Attenuates Oxidative Stress- Induced Intestinal Injury via p38-Mediated Autophagy

Probiotics have been widely used in maintaining intestinal health and one of their benefits is to enhance host antioxidant capacity. However, the involved molecular mechanisms require further investigated. Autophagy is a self-protection process in response to diverse stresses. We hypothesized that probiotics could modulate intestinal autophagy to alleviate oxidative stress. Sprague-Dawley (SD) rats were orally administered Bacillus SC06 or SC08 daily for 24 days and thereafter received an intraperitoneal injection of diquat (DQ) to induce oxidative stress. We found that rats administered Bacillus SC06 showed more significant intestinal tissue repair and antioxidant properties than those administered SC08, which suggests a strain-specific effect of probiotics. Moreover, SC06 alleviated apoptosis by regulating the expression of Bcl2, Bax and cleaved caspase-3. Further investigations revealed that SC06 triggered autophagy, indicated by the upregulation of LC3 and Beclin1 and the degradation of p62 in rat jejunum and IEC-6 cells. Preincubation with autophagy inhibitor 3-methyladenine (3-MA) significantly aggravated reactive oxygen species (ROS) production and apoptotic cell formation. Furthermore, we demonstrated that p38 MAPK (mitogen-activated protein kinase), not AKT (alpha serine/threonine kinase)/mTOR (mammalian target of rapamycin), was involved in SC06-induced autophagy. Taken together, Bacillus SC06 can alleviate oxidative stress-induced disorders and apoptosis via p38-mediated autophagy. The above findings highlight a novel mechanism underlying the beneficial effects of probiotics as functional food and provide a new perspective on the prevention and treatment of oxidative damages.

Could probiotics be the panacea alternative to the use of antimicrobials in livestock diets?

Probiotics are most frequently derived from the natural microbiota of healthy animals. These bacteria and their metabolic products are viewed as nutritional tools for promoting animal health and productivity, disease prevention and therapy, and food safety in an era defined by increasingly widespread antimicrobial resistance in bacterial pathogens. In contemporary livestock production, antimicrobial usage is indispensable for animal welfare, and employed to enhance growth and feed efficiency. Given the importance of antimicrobials in both human and veterinary medicine, their effective replacement with direct-fed microbials or probiotics could help reduce antimicrobial use, perhaps restoring or extending the usefulness of these precious drugs against serious infections. Thus, probiotic research in livestock is rapidly evolving, aspiring to produce local and systemic health benefits on par with antimicrobials. Although many studies have clearly demonstrated the potential of probiotics to positively affect animal health and inhibit pathogens, experimental evidence suggests that probiotics' successes are modest, conditional, strain-dependent, and transient. Here, we explore current understanding, trends, and emerging applications of probiotic research and usage in major livestock species, and highlight successes in animal health and performance.

Probiotic Lactobacillus rhamnosus GG Induces Alterations in Ileal Microbiota With Associated CD3-CD19-T-bet+IFNγ+/- Cell Subset Homeostasis in Pigs Challenged With Salmonella enterica Serovar 4,[5],12:i:

Salmonella enterica serovar 4,[5],12:i:- (S. 4,[5],12:i:-) is an emerging foodborne pathogen causing salmonellosis in humans and animals. Probiotic Lactobacillus rhamnosus GG (LGG) is an effective strategy for controlling enteric infections through maintaining gut microbiota homeostasis and regulating the intestinal innate immune response. Here, LGG was orally administrated to newly weaned piglets for 1 week before S. 4,[5],12:i:- challenge. S. 4,[5],12:i:- challenge led to disturbed gut microbiota, characterized by increased levels of Psychrobacter, Chryseobacterium indoltheticum, and uncultured Corynebacteriaceae populations, as well as an aberrant correlation network in Prevotellaceae NK3B31 group-centric species. The beneficial effect of LGG correlated with attenuating the expansion of Prevotellaceae NK3B31 group. Fusobacterium only found in the pigs treated with LGG was positively correlated with Lactobacillus animalis and Propionibacterium. Administration of LGG induced the expansion of CD3^-CD19^-T-bet⁺IFNγ⁺ and CD3^-CD19^-T-bet⁺IFNγ^- cell subsets in the peripheral blood at 24 h after a challenge of S. 4,[5],12:i:-. S. 4,[5],12:i:- infection increased the population of intraepithelial CD3^-CD19^-T-bet⁺IFNγ⁺ and CD3^-CD19^-T-bet⁺IFNγ^- cells in the ileum; however, this increase was attenuated via LGG administration. Correlation analysis revealed that LGG enriched Flavobacterium frigidarium and Facklamia populations, which were negatively correlated with intraepithelial CD3^-CD19^-T-bet⁺IFNγ⁺ and CD3^-CD19^-T-bet⁺IFNγ^- cells in the ileum. The present data suggest that probiotic LGG alters gut microbiota with associated CD3^-CD19^-T-bet⁺IFNγ^+/- cell subset homeostasis in pigs challenged with S. enterica 4,[5],12:i:-. LGG may be used in potential gut microbiota-targeted therapy regimens to regulate the specific immune cell function and, consequently, control enteric infections.

Lactobacillus johnsonii L531 reduces pathogen load and helps maintain short-chain fatty acid levels in the intestines of pigs challenged with Salmonella enterica Infantis

In the current study, we screened Lactobacillus strains isolated from the colon of clinically healthy weaned piglets for potential probiotic properties and isolated Lactobacillus. johnsonii L531, which produced high levels of beneficial metabolites (butyric, acetic, and lactic acid) in vitro. We also evaluated the efficacy of this metabolites-producing probiotic in treating Salmonella. Infantis infection. Oral administration of L. johnsonii L531 to newly weaned piglets significantly decreased levels of Salmonella colonization in colonic and jejunal contents, accelerated the clearance of Salmonella in feces after infection, and reduced S. Infantis translocation to the spleen. Pretreatment with SCFAs-promoting probiotic L. johnsonii L531 significantly ameliorated the depletion of SCFAs induced by S. Infantis infection and led to significantly greater weight gain and better feed conversion ratios compared to piglets challenged only with S. Infantis. These data provide further evidence that SCFAs-promoting probiotic L. johnsonii L531 treatment could be a suitable nonantibiotic alternative for controlling Salmonella infection and maintaining metabolic homeostasis, thereby enhancing the gut health of piglets during the critical weaning period.

Gut Microbiota and Cancer: From Pathogenesis to Therapy

Cancer is a multifactorial pathology and it represents the second leading cause of death worldwide. In the recent years, numerous studies highlighted the dual role of the gut microbiota in preserving host's health. Gut resident bacteria are able to produce a number of metabolites and bioproducts necessary to protect host's and gut's homeostasis. Conversely, several microbiota subpopulations may expand during pathological dysbiosis and therefore produce high levels of toxins capable, in turn, to trigger both inflammation and tumorigenesis. Importantly, gut microbiota can interact with the host either modulating directly the gut epithelium or the immune system. Numerous gut populating bacteria, called probiotics, have been identified as protective against the genesis of tumors. Given their capability of preserving gut homeostasis, probiotics are currently tested to help to fight dysbiosis in cancer patients subjected to chemotherapy and radiotherapy. Most recently, three independent studies show that specific gut resident species may potentiate the positive outcome of anti-cancer immunotherapy. The highly significant studies, uncovering the tight association between gut microbiota and tumorigenesis, as well as gut microbiota and anti-cancer therapy, are here described. The role of the Lactobacillus rhamnosus GG (LGG), as the most studied probiotic model in cancer, is also reported. Overall, according to the findings here summarized, novel strategies integrating probiotics, such as LGG, with conventional anti-cancer therapies are strongly encouraged.