MRS Broth Research Articles

Role of Prebiotic Inulin extracted from chicory root in Oral care, In-vitro study

Prebiotics are indigestible dietary supplements. Their function is to increase the growth andactivity of beneficial organisms (probiotics) while inhibiting the growth and activity of potentiallyharmful bacteria. The present study evaluated the effectiveness of inulin in enhancing the growthof Lactobacillus sp. and shows antimicrobial activity against Streptococcus mutans a dental cariescausing microorganism. Growth pattern was observed for Lactobacillus plantarum andLactobacillus casei in MRS broth supplemented with 1% inulin and compared with Streptococcusmutans in Brain Heart Infusion Broth supplemented with 1% inulin. Lactobacillus plantarumshowed maximum growth with 0.89 Log10 then Lactobacillus casei with 0.79 Log10 increase andStreptococcus mutans was observed to have only 0.05 Log10 increase. This shows that there is nosuch effect of inulin on the growth of Streptococcus mutans from 0 hr to 24 hr when comparedwith Lactobacillus plantarum and Lactobacillus casei in MRS blank and MRS supplemented with1% inulin and BHIB blank and BHIB supplemented with 1% inulin. Antimicrobial activity ofinulin was also observed against Streptococcus mutans with (12.94±0.14) mm Mean ± SEMzones of inhibition and no zone was observed against Lactobacillus plantarum and Lactobacilluscasei.

Evaluation of the Amino Acid Composition and Content of Organic Acids of Complex Postbiotic Substances Obtained on the Basis of Metabolites of Probiotic Bacteria Lacticaseibacillus paracasei ABK and Lactobacillus helveticus H9

In this article, the probiotic strains of Lacticaseibacillus paracasei ABK and Lactobacillus helveticus H9 were cultured in reconstituted skim milk (RSM medium) and MRS broth, and the cell biomass was removed at the end of fermentation in order to obtain postbiotic substances. In postbiotics, the composition of total amino acids, and also the content of free amino acids and organic acids were analyzed. It was shown that in all RSM-based postbiotic substances the concentration of all free amino acids increased. On the contrary, in the MRS-based postbiotics free amino acids were mostly consumed during fermentation; however, a substantial, two-fold, decrease in methionine concentration was observed in postbiotics obtained with L. paracasei ABK. Both L. paracasei ABK and L. helveticus H9 strains showed change in their fermentation profile from homofermentative in MRS broth to mix-acid fermentation in RSM medium. Both strains produced lactic acid in the investigated media and produced lactate together with acetate in RSM. L. helveticus H9 additionally synthesizes succinic acid on both media. Thus, it has been shown that RSM is more preferable than MRS for fermentation with L. paracasei ABK and L. helveticus H9 for obtaining postbiotics enriched with free amino acids and organic acids.

Lactobacillus crispatus-loaded electrospun fibers yield viable and metabolically active bacteria that kill Gardnerella in vitro

Bacterial vaginosis (BV) is a common condition that affects one-third of women worldwide. BV is characterized by low levels of healthy lactobacilli and an overgrowth of common anaerobes such as Gardnerella. Antibiotics for BV are administered orally or vaginally; however, approximately half of those treated will experience recurrence within 6 months. Lactobacillus crispatus present at high levels has been associated with positive health outcomes. To address the high recurrence rates following BV treatment, beneficial bacteria have been considered as an alternative or adjunct modality. This study aimed to establish proof-of-concept for a new long-acting delivery vehicle for L. crispatus. Here, it is shown that polyethylene oxide (PEO) fibers loaded with L. crispatus can be electrospun with poly(lactic-co-glycolic acid) (PLGA) fibers (ratio 1:1), and that this construct later releases L. crispatus as metabolically viable bacteria capable of lactic acid production and anti-Gardnerella activity. Probiotic-containing fibers were serially cultured in MRS (deMan, Rogosa, Sharpe) broth with daily media replacement and found to yield viable L. crispatus for at least 7 days. Lactic acid levels and corresponding pH values generally corresponded with levels of L. crispatus cultured from the fibers and strongly support the conclusion that fibers yield viable L. crispatus that is metabolically active. Cultures of L. crispatus-loaded fibers limited the growth of Gardnerella in a dilution-dependent manner during in vitro assays in the presence of cultured vaginal epithelial cells, demonstrating bactericidal potential. Exposure of VK2/E6E7 cells to L. crispatus-loaded fibers resulted in minimal loss of viability relative to untreated cells. Altogether, these data provide proof-of-concept for electrospun fibers as a candidate delivery vehicle for application of vaginal probiotics in a long-acting form.

16S rRNA Gene Amplicon Sequencing of Gut Microbiota Affected by Four Probiotic Strains in Mice.

Probiotics, also referred to as "living microorganisms," are mostly present in the genitals and the guts of animals. They can increase an animal's immunity, aid in digestion and absorption, control gut microbiota, protect against sickness, and even fight cancer. However, the differences in the effects of different types of probiotics on host gut microbiota composition are still unclear. In this study, 21-day-old specific pathogen-free (SPF) mice were gavaged with Lactobacillus acidophilus (La), Lactiplantibacillus plantarum (Lp), Bacillus subtilis (Bs), Enterococcus faecalis (Ef), LB broth medium, and MRS broth medium. We sequenced 16S rRNA from fecal samples from each group 14 d after gavaging. According to the results, there were significant differences among the six groups of samples in Firmicutes, Bacteroidetes, Proteobacteria, Bacteroidetes, Actinobacteria, and Desferribacter (p < 0.01) at the phylum level. Lactobacillus, Erysipelaceae Clostridium, Bacteroides, Brautella, Trichospiraceae Clostridium, Verummicroaceae Ruminococcus, Ruminococcus, Prevotella, Shigella, and Clostridium Clostridium differed significantly at the genus level (p < 0.01). Four kinds of probiotic changes in the composition and structure of the gut microbiota in mice were observed, but they did not cause changes in the diversity of the gut microbiota. In conclusion, the use of different probiotics resulted in different changes in the gut microbiota of the mice, including genera that some probiotics decreased and genera that some pathogens increased. According to the results of this study, different probiotic strains have different effects on the gut microbiota of mice, which may provide new ideas for the mechanism of action and application of microecological agents.

Imaging Flow Cytometry Demonstrates Physiological and Morphological Diversity within Treated Probiotic Bacteria Groups

Probiotic bacteria can be introduced to stresses during the culturing phase as an alternative to the use of protectants and coating substances during drying. Accurate enumeration of the bacterial count in a probiotic formulation can be provided using imaging flow cytometry (IFC). IFC overcomes the weak points of conventional, commonly used flow cytometry by combining its statistical power with the imaging content of microscopy in one system. Traditional flow cytometers only collect the fluorescence signal intensities, while IFC provides many more steps as it correlates the data on the measured parameters of fluorescence light with digitally processed images of the analyzed cells. As an alternative to standard methods (plate cell counts and traditional flow cytometry) IFC provides additional insight into the physiology and morphology of the cell. The use of complementary dyes (RedoxSensorTM Green and propidium iodide) allows for the designation of groups based on their metabolic activity and membrane damage. Additionally, cell sorting is incorporated to assess each group in terms of growth on different media (MRS-Agar and MRS broth). Results show that the groups with intermediate metabolic activity and some degree of cellular damage correspond with the description of viable but nonculturable cells.

Purification and Structural Characterization of an Antimicrobial Compound, Lipoxazolidinone a Produced by a Lactobacillus Apis YMP3

ABSTRACT: Strains of Vibrio cholerae are one among the most causative and serious disease causing human pathogenic agents, its infections are caused mostly by ingesting contaminated water and/or food. According to the recent estimates, between 1.3 and 4.0 million individuals are infected all around the world every year. The lactic acid bacteria are an important class of probiotics microbes have their ability to produce diversified bioactive compounds, hence this study focused on the identification of a promising antimicrobial agent from a Lactobacillus apis YMP3. This strain was cultured on MRS broth and the cell free supernatant was ethyl acetate extracted for the antimicrobial agent. The crude extract was further purified with C18 silica gel column chromatography and structurally characterized by FT-IR, NMR, GC and MS/MS spectrum. The chemistry of the compound was confirmed as Lipoxazolidinone A which has the IUPAC name of (2E)-5-butyl-2-[(E)-4-methyl-2-oxoundec-3-enylidene]-1,3-oxazolidin-4-one. This is the first report of Lipoxazolidinone A produced by a bacterium, L. apis YMP3 which was originally isolated from yoghurt. This finding expands the scope of identifying more promising bioactive compounds from probiotic Lactobacillus sp., further, this systematic procedure for purification of this antimicrobial agent stood as the baseline data for more elaborate therapeutic studies in future.

Lactobacillus johnsonii CPN23 vis-à-vis Lactobacillus acidophilus NCDC15 Improves Gut Health, Intestinal Morphometry, and Histology in Weaned Wistar Rats.

The present investigation was carried out with the aim to establish the comparative efficacy of a canine-sourced probiotic meant for canine feeding and a conventional dairy-sourced probiotic. For this purpose, canine-origin Lactobacillus johnsonii CPN23 and dairy-origin Lactobacillus acidophilus NCDC15 were evaluated for potential probiotics health benefits in the rat model. Forty-eight weaned Wistar rats enrolled in this experiment of 8weeks were fed a basal diet and divided into three dietary treatments. Rats of group I enrolled as control (CON) were given MRS placebo at 1mL/head/day, while rats of group II (LAJ) and III (LAC) were administered with overnight MRS broth grown-culture of L. johnsonii CPN23 and L. acidophilus NCDC15, respectively, at 1mL/head/day (108cfu/mL). The average daily gain and net gain in body weight were significantly higher (p < 0.05) in LAJ and LAC than in CON. Fecal and digesta biochemical attributes altered (p < 0.05) positively in response to both probiotics. Total fecal and pooled digesta SCFAs were higher (p < 0.05) in both LAJ and LAC than in CON. The microbial population in cecal and colonic digesta responded (p < 0.05) positively to both probiotics. The diameter of intestinal segments was higher (p < 005) in LAJ as compared to CON. The number and height of villi in jejunum tended to be higher in LAJ as compared to CON. The humoral immune response to sheep erythrocytes as well as chicken egg-white lysozyme was higher in LAJ as compared to CON. Overall, the results of the study have demonstrated the effectiveness of the canine-sourced L. johnsonii CPN23 as a potential probiotic, with a comparatively better response than the dairy-sourced L. acidophilus NCDC15. It could thus be recommended for use in feeding dogs to help augment their health.

Purification and Partial Characterization of a Bacteriocin Produced by Lactobacillus pentosus 124-2 Isolated from Dadih

The fermentation process results in the presence of lactic acid bacteria (LAB). Traditional fermented buffalo milk from the Indonesian province of West Sumatra is known as dadih. Bacteriocins are naturally occurring antimicrobial peptides that can be produced by LAB. These bacteriocins have the potential to be used as natural preservatives. This research was conducted with the intention of isolating and partially characterizing a bacteriocin that was generated by Lactobacillus pentosus 124-2 that was isolated from dadih. Using MRS agar media and 16sRNA, the LAB that was found in dadih was successfully isolated. Bacteriocins were produced using media consisting of MRS broth. After the bacteriocins were obtained, they were subjected to a series of purification processes, one of which included ammonium sulfate (70%) followed by gel filtration chromatography for additional purification. According to the findings, the strain of LAB that was discovered in the dadih was Lactobacillus pentosus 124-2. The specific activity of the bacteriocins rose, allowing for the effective completion of the purification process. The pure bacteriocins had the greatest specific activity values, at 60.59 AU/mg, while the yield values were 0.41% and 3.15-fold. Bacteriocins in their purest form were able to inhibit the growth of Salmonella species as well as Staphylococcus aureus. The characterization results included partial bacteriocins that were resistant to pH 2, 4, and 6; antibacterial activity that was was stable at a temperature range of 25 °C to 121 °C; and resistance to the addition of 2%, 4%, and 6% salt concentrations. Microbial stability against the addition of surfactants EDTA, SDS, and Tween 80 was also obtained. In light of these findings, a bacteriocin derived from L. pentosus possesses the possible ability to be utilized in the food business as a biopreservative.

Effects of the cultivation conditions on antimicrobial activity of Lactiplantibacillus sp. NCL33 isolated from Nem chua

There is an increasing demand from consumers for natural and minimally processed foods. Therefore, developing and producing effective natural antimicrobial substances for food preservation is of great interest. This work aimed to investigate the effect of growth conditions on the maximum activity of antibacterial substances production by Lactiplantibacillus sp. NCL33 from Nem chua, a traditional fermented meat. The results revealed that the antibacterial substances exhibited a broad spectrum of antimicrobial activity against Gram-positive and Gram-negative bacteria. The antibacterial activity of NCL33 was optimized with MRS broth supplemented with 20 g/L glucose. The suitable nitrogen source for antibacterial biosynthesis was yeast extract with a concentration of 25 g/L. Moreover, the inoculated temperature and initial pH significantly influenced the antimicrobial activity. The maximum antimicrobial activity of NCL33 was obtained at 30&amp;deg;C and pH 7,0. &amp;nbsp;

Plasmid-Associated Bacteriocin Produced by Pediococcus pentosaceus Isolated from Smoked Salmon: Partial Characterization and Some Aspects of his Mode of Action.

Strain ST3Ha, isolated from commercially available smoked salmon, was identified as Pediococcus pentosaceus based on biochemical and physiological tests and 16S rRNA sequencing. Strain ST3Ha produces a class IIa bacteriocin active against lactic acid bacteria, Listeria monocytogenes and Enterococcus faecalis. The antimicrobial peptide was inactivated by proteolytic enzymes, confirming his proteinaceous nature, but was not affected when treated with α-amylase, SDS, Tween 20, Tween 80, urea, and EDTA. No change in activity was recorded after 2h at pH values between 2.0 and 9.0 and after treatment at 100°C for 120min or 121°C for 15min. The mode of action against Listeria ivanovii subsp. ivanovii ATCC 19119 and E. faecalis ATCC 19443 was bactericidal, resulting in cell lyses and enzyme leakage. The highest level of activity (1.6 × 106 AU/mL) was recorded when cells were grown at 37°C or 30°C in MRS broth (pH 6.5). Antimicrobial peptide ST3Ha adsorbs at high levels to the sensitive test organisms on strain-specific manner and depending on incubation temperature, environmental pH, and presence of supplemented chemicals. Based on PCR analysis, P. pentosaceus ST3Ha harbor a 1044-bp plasmid-associated fragment corresponding in size to that recorded for pediocin PA-1. Sequencing of the fragment revealed a gene identical to pedB, reported for pediocin PA-1. The combined application of the low levels (below MIC) of ciprofloxacin and bacteriocin ST3Ha results in the synergetic effect in the inhibition of L. ivanovii subsp. ivanovii ATCC 19119. Expressed by P. pentosaceus ST3Ha, bacteriocin was characterized as low cytotoxic, a characteristic relevant for its application in food industry and/or in human and veterinary medical practices.

Bacteriocinogenic Enterococcus casseliflavus Isolated from Fresh Guava Fruit (Psidium guajava): Characterization of Bacteriocin ST192Gu and Some Aspects of Its Mode of Action on Listeria spp. and Enterococcus spp.

Strain ST182Gu, isolated from fresh guava fruit, was identified as Enterococcus casseliflavus on the basis of biochemical tests, sugar fermentation reactions (API20Strip), PCR with genus-specific primers, and 16S rRNA sequencing. This appears to be the first documentation of the presence of this species in guava. E. casseliflavus ST182Gu was shown to produce a 4.8 kDa class IIa bacteriocin, active against various lactic acid bacteria including Enterococcus spp. and Streptococcus spp., and Staphylococcus aureus, and different serotypes of Listeria spp. The activity of the peptide was reduced by treatment with 0.1 mg/mL proteolytic enzymes, but not by α-amylase, catalase, lipase, and 1% (w/v) sodium dodecyl sulphate (SDS), Tween-20, Tween-80, urea, NaCl, and EDTA. No change in activity was recorded after adjustment to pH values of between 2.0 and 12.0 for 2 h, and after treatment at 100 °C for 120 min or 121°C for 20 min, compared with non-treated antimicrobial peptide. The mode of action against representative susceptible bacteria was shown to be bactericidal and associated with cell lysis and enzyme- and DNA-leakage. These susceptible bacteria, Listeria ivanovii subsp. ivanovii ATCC 19119, Listeria monocytogenes ATCC 15313, and Enterococcus faecalis ATCC 19443 differed however in their sensitivity to bacteriocin ST182Gu (6,553,600 AU/mL, 102,400 AU/mL, and 51,200 AU/mL, respectively). No significant differences were detected in cell growth and bacteriocin production when strain ST182Gu was grown in MRS broth at 26 °C, 30 °C, and 37 °C for 24 h. Bacteriocin ST182Gu recovery from the surface of the producer cells showed different activity, dependent of the applied test organisms (3200, 800 and 400 AU/mL, evaluated versus L. ivanovii subsp. ivanovii ATCC 19119, L. monocytogenes ATCC 15313 and E. faecalis ATCC 19443, respectively), however, with proportional values with the activity recorded in cell free supernatant versus same test microorganisms. When bacteriocin ST182Gu was combined with sublethal doses of ciprofloxacin, synergistic inhibition of L. ivanovii subsp. ivanovii ATCC 19119 was demonstrated. This increase in ciprofloxacin sensitivity may be due to the dissipation of the proton gradient in the cell membrane of the target organism associated with exposure to bacteriocin ST182Gu. Apart from reducing the MIC of classical therapeutic antibiotics, bacteriocins such as ST182Gu may also play an important role in the treatment of multidrug resistant strains.

Exopolysaccharide-producing Lacticaseibacillus paracasei strains isolated from kefir as starter for functional dairy products.

Exopolysaccharides (EPS) produced by lactic acid bacteria are molecules of great interest for the dairy food industry. Lacticaseibacillus paracasei CIDCA 8339, CIDCA 83123, and CIDCA 83124 are potentially probiotic strains isolated from kefir grains whose EPS-production on MRS broth is dependent on incubation temperature. The aim of the present work is to evaluate the effect of fermentation temperature on the characteristics of EPS produced in milk by L. paracasei strains and the consequent impact on the rheological properties of the fermented products. Additionally, the protective effect of these EPS against Salmonella infection was evaluated in vitro. Acid gels with each strain were obtained by milk fermentation at 20°C, 30°C, and 37°C evidencing for all the strains a reduction in growth and acidification rate at lower temperature. Lacticaseibacillus paracasei CIDCA 83123 showed low fermentation rate at all temperatures requiring between 3 and 8 days to obtain acids gels, whereas CIDCA 8339 and 83124 needed between 24 and 48 h even when the temperature was 20°C. Fermentation temperature led to changes in crude EPS characteristics of the three strains, observing an increase in the relative amount of the high molecular weight fraction when the fermentation temperature diminished. Additionally, EPS83124 and EPS83123 presented modifications in monosaccharide composition, with a reduction of rhamnose and an increase of amino-sugars as temperature rise. These changes in the structure of EPS83124 resulted in an increase of the apparent viscosity of milks fermented at 20°C (223 mPa.s) and 30°C (217 mPa.s) with respect to acid gels obtained at 37°C (167 mPa.s). In order to deepen the knowledge on EPS characteristics, monosaccharide composition of low and high molecular weight EPS fractions were evaluated. Finally, it was evidenced that the preincubation of intestinal epithelial cells Caco-2/TC-7 with EPS8339 and EPS83124 partially inhibit the association and invasion of Salmonella. In light of these results, it can be concluded that the selection of the EPS-producing strain along with the appropriate fermentation conditions could be an interesting strategy to improve the technological properties of these L. paracasei fermented milks with potential protective effects against intestinal pathogens.

ANTIBACTERIAL ACTIVITY AND IDENTIFICATION OF PRODUCED REUTERIN FROM LOCAL Lactobacillus reuteri LBIQ1 ISOLATE

Reuterin was anaerobically manufactured by developing Lactobacillus reuteri LBIQ1 (a local isolate) at 37 °C in the MRS broth medium. Cell biomass was harvested after 18 hours of incubation and used to ferment 278 mMol glycerol for 3 hours in a water-glycerol solution at 37 °C. Cells were then extracted from the suspension solution, which remained at 4 °C until colorimetric, UV, and HPLC assays observed the presence of reuterin in the solution. The reuterin compound has inhibitory activity against Gram-positive and Gram-negative bacteria. The highest inhibition zones measured were 23mm and 21mm against Staphylococcus aureus and Escherichia coli, respectively. The UV chromatogram of produced reuterin showed one peak at 280 nm, while HPLC analysis were appeared three peaks at 6.48, 15.6 min, and 15.49 min for the injection peak, residual glycerol, and produced reuterin, respectively. After incubation for 3 hours, a total yield of 167.382 L/ml reuterin was estimated as the productivity of L. reuteri LBIQ1in the glycerol-water solution. The highest inhibition zones of pure reuterin against S. aureus and E. coli were 44 and 39 mm, respectively. Reuterin is an effective compound against microorganisms that can be produced from glycerol media and used in food preservation.

Characterization of Two Mannitol-Producing Leuconostoc Strains from Pa-Kimchi and Their Application for Juice and Yogurt Fermentation.

Two mannitol producing lactic acid bacteria were isolated from pa (green onion)- kimchi, identified and named as Leuconostoc mesenteroides SKP 88 and Leuconostoc citreum SKP 92, respectively. Both isolates grew well at 25-30oC, initial pH 6-8, and 3% and lower NaCl concentration. Both isolates converted fructose into mannitol efficiently when grown on MRS broth containing fructose and glucose. Glucose was used as a carbon source and fructose was used as a precursor for mannitol. Mannitol yields were the highest in MRS broth with 3% fructose and 2% glucose. Shine muscat juice fermentation was done using each isolate as a starter. As fermentation progressed, decrease in pH and increases in titratable acidity and viable counts were observed. L. mesenteroides SKP 88 showed better mannitol conversion ability than L. citreum SKP 92, and shine muscat juice fermented with L. mesenteroides SKP 88 showed the mannitol production of 41.6 g/l at 48 h, and juice fermented with L. citreum SKP 92 showed 23.4 g/l at the same time. Yogurt fermentations showed similar patterns, and yogurt fermented with L. mesenteroides SKP 88 showed the mannitol production of 15.13 g/l. These results showed that both strains are useful as starters for healthy fermented foods with reduced fructose contents.

The immunomodulating effect of bifidobacteria is modified by the anticoagulant acenocoumarol

Bifidobacteria are health promoting microorganisms that can interact with drugs in the intestinal tract thus modifying the activation of immune cells and host homeostasis. To study the effect of acenocoumarol on the interaction between bifidobacteria and THP-1 cells or intestinal epithelial cells. Bifidobacterium bifidum CIDCA 5310 and B. adolescentis CIDCA 5317 were grown in MRS broth in anaerobic conditions. The experiments were done in the presence of acenocoumarol. FITC-labeled bacteria were incubated with THP1 cells differentiated with PMA (THP1-PMA), and phagocytosis and intracellular localization of bacteria were assessed by flow cytometry and confocal laser microscopy, respectively. Also, expression of macrophage surface molecules in THP1 and THP1-PMA cells was assessed by flow cytometry. By using the Caco-2 ccl20:luc reporter system innate immune response was analysed by determining luciferase expression induced by flagellin. Acenocoumarol decreased phagocytosis of bifidobacteria but intracellular routing was not modified. Also, anticoagulant reduced the expression of HLA-DR and CD64 induced by bifidobacteria in both THP1-PMA and THP1 cells. Instead, the decrease in the expression of CD206 and CD23 was dependent on differentiation status of THP1 cells. Acenocoumarol increased CCL20 expression and it was partially abrogated by strain CIDCA 5310. Presence of acenocoumarol modifies the interaction between bifidobacteria and eukaryotic cells thus suggesting that the expected modulation of immune response by probiotic foods can be different in persons under anticoagulant treatment.

Prebiotic potential of Azolla pinnata (R.Br.) and dietary inclusion effect of pulverised azolla on the growth performance of milkfish fingerlings

The growth of the aquaculture sector leads to a demand for sustainable feed ingredients. Prebiotics are potential sustainable feed ingredients that can promote the improved performance of aquaculture species without the use of antimicrobials. This study investigated the potential of Azolla pinnata as a candidate prebiotic source. Prebiotic characteristics and dietary effect of commercial diet (CD) with varying pulverised azolla (PA) inclusion was evaluated. Results showed that PA (9.40% moisture) constitutes around 16.1% ash, 22.3% crude fibre, 20.9% crude protein, 1.7% crude fat and 29.6% nitrogen-free extract. Crude xylan and cellulose content of PA were 13.7% and 12.6% dry matter (DM) respectively. Growth of Lactobacillus rhamnosus in PA-supplemented MRS broth remarkably improved after 4 to 6 hours of incubation. Feeding trials results revealed that PA inclusion had no adverse effect on average survival of milkfish fingerlings, albeit significant improvement (p &lt; 0.01) was noted in group fed with 2% PA-replaced CD in terms of the total weight gain (119.9%), specific growth rate (2.62% day–1) and feed efficiency (79.9%). The present study demonstrated the prebiotic activity of PA, as well as its potential use as dietary feed component for improved growth and feed efficiency of cultured milkfish.

Characterization of a Potential Probiotic Lactiplantibacillus plantarum LRCC5310 by Comparative Genomic Analysis and its Vitamin B6 Production Ability.

Safety assessment and functional analysis of probiotic candidates are important for their industrial applications. Lactiplantibacillus plantarum is one of the most widely recognized probiotic strains. In this study we aimed to determine the functional genes of L. plantarum LRCC5310, isolated from kimchi, using next-generation, whole-genome sequencing analysis. Genes were annotated using the Rapid Annotations using Subsystems Technology (RAST) server and the National Center for Biotechnology Information (NCBI) pipelines to establish the strain's probiotic potential. Phylogenetic analysis of L. plantarum LRCC5310 and related strains showed that LRCC5310 belonged to L. plantarum. However, comparative analysis revealed genetic differences between L. plantarum strains. Carbon metabolic pathway analysis based on the Kyoto Encyclopedia of Genes and Genomes database showed that L. plantarum LRCC5310 is a homofermentative bacterium. Furthermore, gene annotation results indicated that the L. plantarum LRCC5310 genome encodes an almost complete vitamin B6 biosynthetic pathway. Among five L. plantarum strains, including L. plantarum ATCC 14917T, L. plantarum LRCC5310 detected the highest concentration of pyridoxal 5'-phosphate with 88.08 ± 0.67 nM in MRS broth. These results indicated that L. plantarum LRCC5310 could be used as a functional probiotic for vitamin B6 supplementation.

Identification and characterization of probiotics isolated from indigenous chicken (Gallus domesticus) of Nepal.

Excessive and irrational use of antibiotics as growth promoters in poultry has been one of key factors contributing to increased emergence of antibiotics resistant bacteria. Several alternatives for antibiotic growth promoters are being sought, and the search for effective probiotics to be used as feed additives is amongst the promising ones. Our study aimed to isolate and test potential probiotics bacteria from cloacal swabs of various indigenous chicken (Gallus domesticus) breeds from rural outskirts of the Kathmandu valley (Nepal). Selective isolation of probiotics was conducted by micro-aerophilic enrichment of sample in MRS Broth at 37°C, followed by culturing on MRS agar supplemented with 5 g/L of CaCO3. Isolated bacterial colonies producing transparent halo were selected as potential lactic acid bacteria (LAB), and tested for their antibacterial activity, phenotypic and biochemical characteristics, acidic yield, and tolerance to acid and bile. A total of 90 potential LAB were isolated from cloacal samples collected from 41 free-ranging chickens of indigenous breeds. Of these, 52 LAB isolates (57%) showed variable antibacterial activity to at least one bacterial pathogen. Of 52 LAB, 46 isolates fulfilled phenotypic and biochemical criteria of Lactobacillus spp. Of these, 37 isolates produced varying percentage yields of lactic acid, 27 isolates showed survival at pH 3.0, and 17 isolates showed survival tolerances in the presence of 0.3% and 0.5% bile salts for 24 hours. Phylogenetic analysis of 16S rDNA sequencing of LAB isolates fulfilling in vitro probiotics properties showed that 3 isolates had genetic identity of 99.38% with Lactobacillus plantarum, while one isolate was genetically similar (99.85%) with the clade of L. reuteri, L. antri and L. panis. Our study identified four Lactobacillus spp. strains having potential probiotics properties. Further investigations are needed to evaluate these isolates to be used as poultry probiotics feed supplement.

Culture Age, Growth Medium, Ultrasound Amplitude, and Time of Exposure Influence the Kinetic Growth of Lactobacillus acidophilus

The growth pattern of probiotics can be modified by changing their nutritional factors and their physiological stage. Meanwhile, high intensity ultrasound (HIUS) can be employed to increase probiotics’ biomass. The one-factor-at-a-time (OFAT) approach was employed to investigate the influence of the growth medium (MRS broth, whole milk, and skim milk), culture age (1 day and 7 days old) and ultrasound parameters (time and amplitude) on the kinetic parameters of L. acidophilus. The oldest culture (7 days) had a greater lag phase and time to reach the end of the sigmoidal curve (Tmax) (p &lt; 0.05) as well as a lower rate (maximum growth potential μmax) compared to the youngest culture (1 day). Regarding the growth medium, skim milk presented the greatest L. acidophilus counts (p &lt; 0.05). Meanwhile, sonication times (60 and 90 s) change µmax and Tmax. When 30% amplitude was applied, a greater μmax and a smaller Tmax were observed (p &lt; 0.05). It can be concluded that the growth medium, culture age, and ultrasound parameters (time and amplitude) influence the kinetic parameters of L. acidophilus. Results from this study could be used in the design and optimization of processes to improve the growth of the probiotic L. acidophilus at industrial scale.

Effects of ambient temperature and available sugar on bacterial community of Pennisetum sinese leaf: An in vitro study.

The present in vitro study investigated the effects of temperature and available sugar on the bacterial community of Pennisetum sinese leaf during fermentation. P. sinese leaves were cultured in MRS broth containing 0.4 and 1.6 g sugar and incubated at 25°C and 45°C for 9, 18, and 36 h. The results showed that the dominant phyla during sugar fermentation were Firmicutes, followed by Proteobacteria and Bacteroidetes. Compared to a low incubation temperature (25°C), a high incubation temperature (45°C) decreased the relative abundances of Exiguobacterium and Acinetobacter and increased those of Bacillus and Paenibacillus. Leaf samples incubated at 25°C showed higher bacterial alpha diversity indices than those incubated at 45°C. Principal coordinate analysis revealed that the bacterial community structure was altered by the high incubation temperature. Sugar concentration of 1.6 g/50 ml increased the relative abundances of Bacillus and Klebsiella but decreased those of Paenibacillus and Serratia as compared to sugar concentration of 0.4 g/50 ml. pH was the primary factor that influenced the succession of bacterial communities during sugar fermentation in P. sinese leaves. In conclusion, ambient temperatures (25°C and 45°C) and high sugar concentration restructured the bacterial communities on P. sinese leaves by facilitating the dominance of Bacillus and Paenibacillus. This study provided insights into the mechanisms by which bacterial communities on P. sinese leaves are enriched.