Oral administration of Enterococcus faecalis EC-12 cell preparation improves villous atrophy after weaning through enhancement of growth factor expression in mice

Effects of Clostridium butyricum and Enterococcus faecalis on growth performance, intestinal structure, and inflammation in lipopolysaccharide-challenged weaned piglets

This study was conducted to investigate the effects of Clostridium butyricum and Enterococcus faecalis on growth performance, immune function, inflammation-related pathways, and microflora community in weaned piglets challenged with lipopolysaccharide (LPS). One hundred and eighty 28-d-old weaned piglets were randomly divided into 3 treatments groups: piglets fed with a basal diet (Con), piglets fed with a basal diet containing 6 × 109 CFU C. butyricum·kg-1 (CB), and piglets fed with a basal diet containing 2 × 1010 CFU E. faecali·kg-1 (EF). At the end of trial, 1 pig was randomly selected from for each pen (6 pigs per treatment group) and these 18 piglets were orally challenged with LPS 25 μg·kg-1 body weight. The result showed that piglets fed C. butyricum and E. faecalis had greater final BW compared with the control piglets (P < 0.05). The C. butyricum and E. faecalis fed piglets had lower levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), IL-1β, tumor inflammatory factor-α (TNF-α), and had greater level of serum interferon-γ (IFN-γ) than control piglets at 1.5 and 3 h after injection with LPS (P < 0.05). Furthermore, piglets in the C. butyricum or E. faecalis treatment groups had a greater ratio of jejunal villus height to crypt depth (V/C) compared with control piglets after challenge with LPS for 3 h (P < 0.05). Compared with the control treatment, the CB and EF treatments significantly decreased the expression of inflammation-related pathway factors (TLR4, MyD88, and NF-κB) after challenge with LPS for 3 h (P < 0.05). High-throughput sequencing revealed that C. butyricum and E. faecalis modulated bacterial diversity in the colon. The species richness and alpha diversity (Shannon) of bacterial samples in CB or EF piglets challenged with LPS were higher than those in LPS-challenged control piglets. Furthermore, the relative abundance of Bacteroidales-Rikenellanceae in the CB group was higher than that in the control group (P < 0.05), whereas EF piglets had a higher relative abundance of Lactobacillus amylovorus and Lactobacillus gasseri (P < 0.05). In conclusion, dietary supplementation with C. butyricum or E. faecalis promoted growth performance, improved immunity, relieved intestinal villus damage and inflammation, and optimized the intestinal flora in LPS-challenged weaned piglets.

Production, Absorption, and Blood Flow Dynamics of Short-Chain Fatty Acids Produced by Fermentation in Piglet Hindgut during the Suckling⁻Weaning Period

Luminal short-chain fatty acids (SCFA) are rapidly absorbed from the intestine and subsequently utilized by the host as substrate for metabolic energy production. In pigs, the energy contribution of SCFA is thought to be 30⁻76%. However, since absorption and blood flow dynamics of SCFA in pigs, particularly during the suckling⁻weaning period, remain unclear, we aimed to elucidate these phenomena. Thirty-two piglets were used in the present work. Cecal vein blood and digesta, and portal and abdominal vein blood were sampled from suckling (7-, 14-, 21- and 28-day-old) and weaned (weaning at 21 and 28 days of age) piglets. Four piglets from each group were euthanized. SCFA concentrations in blood samples were analyzed by a highly sensitive gas chromatography-mass spectrometry technique. Age at weaning tended to affect SCFA absorption. For example, acetate and propionate concentrations in the cecal vein tended to be higher in piglets weaned at day 21 than at day 28. SCFA concentrations in the abdominal vein tended to differ from those in other veins. Mucosal gene expression analysis suggested that monocarboxylate transporter 1 and occludin were associated in absorption of SCFA from the lumen into the blood of piglets.

Stimulation of murine cell-mediated immunity by dietary administration of a cell preparation of Enterococcus faecalis strain KH-2 and its possible activity against tumour development in mice

It is well known that dietary lactic acid bacteria (LAB) stimulate cell-mediated immunity such as natural killer (NK) activity in mice. Here, we aimed to assay the immunomodulatory effects of a cell preparation of Enterococcus faecalis strain KH-2 (CPEF). We further evaluated the possibility of antitumour activity caused by CPEF administration, because NK cells actively participate in the prevention of tumour formation. NK cell activity and gene expression of IFN-γ and Perforin 1, which were induced most likely by a synergetic action of their cytotoxic activity, were higher in splenocytes of CPEF-administered mice than they were in control mice. Moreover, unlike those of control mice, the splenocytes of CPEF-administered mice had significantly higher CD28⁺CD69⁺/CD4⁺ and CD28⁺CD69⁺/CD8⁺ ratios that resulted in a survival rate with a tendency toward improvement after 47 days of CPEF administration (p=0.1) in Meth-A fibrosarcoma-bearing mice. In conclusion, we showed that CPEF might be effective in treating Meth-A fibrosarcoma in mice, as it helped increase their survival rate via stimulation of an immune response in splenocytes, which involved systemic cellular immunity processes such as cytotoxic activity, and active T cells.

Characterization and Application of Antilisterial Enterocins on Model Fresh Cheese

Enterococcus faecalis strains isolated from an artisanal cheese were selected based on enterocin production against Listeria monocytogenes. The strains formed biofilms and presented high hydrophobic character and good autoaggregation and coaggregation capacity with L. monocytogenes. Strains L3A21M3 and L3B1K3 presented high survival under gastrointestinal conditions, were able to adhere to human intestinal cells (Caco-2 and HT-29), and blocked the adhesion and invasion of L. monocytogenes. The antilisterial activity of enterocins was not affected by pH (2 to 12), heating (100°C), and chemical and surfactant agents. However, strains L3A21M3 and L3A21M8 produced thermolabile enterocins, which were also sensible to extreme pH values. Enterocins exhibited a bacteriostatic mode of action against L. monocytogenes, and maximum production was observed during the stationary phase. Common enterocin structural genes were not detected by PCR amplification with specific primers, although an exhaustive screening was not performed. The enterocin produced by the L3B1K3 strain was purified and applied to model cheeses contaminated with L. monocytogenes. This enterocin reduced survival of L. monocytogenes on fresh cheeses in a dose-dependent manner. The highest dose tested (2,048 arbitrary units per g of cheese) was effective in reducing the pathogen counts to undetectable values throughout storage (6 to 72 h). These results suggest that these strains have great potential to be used as biopreservatives in the food industry and also as probiotics, with the potential to prevent L. monocytogenes gastrointestinal infection.

Differential expression of genes encoding neurotrophic factors and their receptors along the septal-temporal axis of the rat hippocampus

The hippocampus plays a key role in learning and emotional regulation. The hippocampus' function varies along its septotemporal axis, with the septal pole being more frequently involved in spatial learning and memory, and the temporal pole playing a greater role in emotional behaviors. In this study, we present findings aimed at checking the expression level of the genes encoding neurotrophins and their receptors, including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and their receptors (TrkA, TrkB and TrkC) in the hippocampus along the septotemporal axis. Using real-time PCR, several different expression patterns were observed. Remarkably, the expression of both NT-3 and TrkA genes in the septal hippocampus was higher than in the middle and temporal hippocampus. Higher expression of NT-3 and TrkA may implicate active neurogenesis in the dentate gyrus (DG) of the septal hippocampus because more neurogenesis occurs in the septal than the temporal DG of rats. Finally, the results obtained in this study emphasize the importance of choosing the hippocampal portion along its septotemporal axis for any hippocampal molecular and biochemical experimental studies.

Antioxidant status and hormonal profile reflected by experimental feeding of probiotics

Excessive production of free radicals can result in tissue damage, which mainly involves generation of hydroxyl radical and other oxidants. Such free radical-induced cell damage appears to play a major role in the pathogenesis of many diseases. Probiotics have been used therapeutically to modulate immunity, improve digestive processes, lower cholesterol, treat rheumatoid arthritis, and prevent cancer. The proposed research was designed to evaluate the changes in oxidative and antioxidative profile in addition to metabolic-related hormones of living animal model, which may generally affect the health status. Two groups of rabbits (10 animals each) were allocated in hygienic cages of controlled animal house. Control group received standard diet, and the other group received the same diet containing one probiotic for 30 days. Lactate dehydrogenase (LDH) activity in leukocytes, blood glucose, reduced glutathione (GSH), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) were estimated in different tissues. Malondialdehyde (MDA) and total proteins were also determined in different tissues. Certain hormones related to metabolism and growth were also evaluated. Leukocytic LDH activity was significantly increased along with nonsignificant increase of blood glucose in probiotics-fed animals. Results showed significant decreases in the levels of triiodothyronine and thyroid-stimulating hormone but showed significant elevations in thyroxine, insulin, growth hormone, and testosterone levels in animals fed with probiotics. Total proteins content was highly significantly elevated in liver, kidneys, and muscles of probiotic-administered animals. Microsomal GSH level was significantly decreased only in skeletal muscles of probiotic-treated animals. MDA was significantly lowered in animal tissues fed with probiotics. GSH-Px activity was elevated in hepatic and muscular microsomes of probiotic-supplemented animals while it was nonsignificantly increased in renal microsomes. Microsomal SOD activity was elevated in liver, kidneys, and skeletal muscles of probiotics-administrated animals. It is concluded that supplementation of probiotic may enhance antioxidant efficacy and scavenge free radicals and thus may be used as a preventive measure for protection against free radicals-induced disorders.

Biodiversity of Enterococcus faecalis based on genomic typing

Enterococcus faecalis is a common inhabitant of the gastrointestinal tracts of different animals and is also found in other environments, such as plants, soil, food and water. The diverse nature of E. faecalis, which includes pathogenic, commensal and probiotic strains, calls for the development of tools for accurate discrimination and characterization at the strain level. Here we studied the genetic relationships among 106 E. faecalis strains isolated from diverse origins and possessing different degrees of virulence. Strain typing was conducted using a set of selected simple-sequence repeat (SSR) loci combined with multilocus sequence typing (MLST) analysis, which discriminated among the strains and separated them into three main clusters. While pathogenic and commensal isolates were dispersed along the dendrogram, probiotic and cheese-originated strains were highly associated with one specific cluster (cluster 1). The strain panel was further characterized by testing the occurrence of two virulence determinants (esp gene and β-hemolysis). The two determinants showed low abundance among probiotic and cheese-originated strains within cluster 1 when compared to non-cluster 1 cheese-originated strains, indicating a possible association of cluster 1 with non-virulent strains. Our results further emphasize the importance and challenge of precise characterization of E. faecalis strains from various sources.