Alternatives to antibiotic use: probiotics for the gut

The Effect of Using Bovine Colostrum and Probiotics on Performance, Egg Traits, Blood Biochemical and Antioxidant Status of Laying Japanese Quails

The present paper aims to evaluate the effect of different levels of bovine colostrum and probiotic dietary supplementation on egg production performance, egg traits, carcass characteristics, blood biochemistry and antioxidant status of laying Japanese quails. For the trial, 240 laying quails, aged between 24 weeks and 30 weeks, were involved in a 3 × 2 factorial experimental design, with 3 levels of bovine fresh colostrum (0, 2, and 4 percent of the total ratio) and 2 levels of probiotics (0 and 0.01 percent of the total ratio) administration. The colostrum supplementation improved the egg production performance, egg traits, carcass characteristics, blood biochemistry, and antioxidant status (p < 0.01). Probiotics used without colostrum did not affect the investigated traits of laying Japanese quails (p > 0.05), but a synergistic effect was observed when combined with colostrum. The overall results recommended that using 4% of bovine colostrum in laying Japanese quails, with the addition of 0.01% of probiotic feed additive results in positive effects on egg production performance, egg traits, carcass characteristics, blood biochemistry, and antioxidant status of laying Japanese quails in the late laying period.

Lactobacillus crispatus DSM25988 as novel bioactive agent to co-aggregate Streptococcus pyogenes and to exclude it by binding to human cells

Streptococcus pyogenes, a group A streptococcus, is the major bacterial pathogen responsible for acute bacterial infection of the human oropharynx and the causative agent of scarlet fever. Estimates of the global burden of S. pyogenes related diseases revealed 616 million cases of pharyngitis, and at least 517,000 deaths due to severe invasive diseases and sequelae. Here we describe Lactobacillus crispatus DSM25988 that was identified among hundreds of Lactobacillus strains (referring to all organisms that were classified as Lactobacillaceae until 2020) showing ability to prevent adhesion of S. pyogenes to Detroit 562 cells, and to exhibit a masking and co-aggregating effect on S. pyogenes in vitro. L. crispatus DSM25988 also inhibits invasion of cultured human epithelial pharyngeal cells by S. pyogenes. Competitive binding to fibronectin might be involved in the inhibition process. Antiviral activity of the L. crispatus DSM25988 cells were identified in an in vitro cell model demonstrating that L. crispatus effectively excludes viruses from epithelial cells using SARS-CoV2 proteins as a model. This finding points to the potential of DSM25988 to protect cells from virus infection. Biological activity is retained in heat treated cells. The heat-treated Lactobacillus strain was further developed into functional throat lozenges, wherein its biological activity is stably maintained in the formulation. Lozenges containing L. crispatus DSM25988 underwent testing in an uncontrolled, prospective user study in 44 subjects with symptoms of sore throat for a period of up to 14 days. The study data shows promising safety and efficacy of the medical device when used against symptoms of sore throat like scratchy feeling, hoarse voice and swallowing pain.

Probiotics-Live Biotherapeutics: a Story of Success, Limitations, and Future Prospects-Not Only for Humans

In livestock production, lactic acid bacteria (LAB) represent the most widespread microorganisms used as probiotics. For such critical use, these bacteria must be correctly identified and characterized to ensure their safety and efficiency. Recently, probiotics have become highly recognized as supplements for humans and in particular for animals because of their beneficial outcome on health improvement and well-being maintenance. Various factors, encompassing dietary and management constraints, have been demonstrated to tremendously influence the structure, composition, and activities of gut microbial communities in farm animals. Previous investigations reported the potential of probiotics in animal diets and nutrition. But a high rate of inconsistency in the efficiency of probiotics has been reported. This may be due, in a major part, to the dynamics of the gastrointestinal microbial communities. Under stressing surroundings, the direct-fed microbials may play a key role as the salient limiting factor of the severity of the dysbiosis caused by disruption of the normal intestinal balance. Probiotics are live microorganisms, which confer health benefits on the host by positively modifying the intestinal microflora. Thus, the aim of this review is to summarize and to highlight the positive influence of probiotics and potential probiotic microbe supplementation in animal feed with mention of several limitations.

Xylanase and Direct-Fed Microbials (DFM) Potential for Improvement of Live Performance, Energy Digestibility, and Reduction of Environmental Microbial Load of Broilers

The challenge of identifying alternatives to subtherapeutic levels of antibiotic growth promoters (AGP) in animal feed has led to increased interest in feed additives such as exogenous enzymes and direct-fed microbials (DFM). Six corn soy-based dietary treatments were designed to investigate the effect of high-efficiency xylanase alone, Bacillus spp. probiotics alone, and their combination vs. a commonly used antibiotic growth promoter (bacitracin methylene disalicylate; BMD) on live performance and environmental Clostridium perfringens load of broiler chickens with eight replicate pens per treatment. Diets were as follows: standard diet (positive control; PC); 130 kcal/kg reduced-energy diet (negative control; NC); NC with xylanase (NC + Xy); NC with probiotics (NC + Pro); NC with xylanase and probiotics mix (NC + XyPro); and NC with BMD (NC + BMD). Data were analyzed as one-way ANOVA. At 35 and 42 days, birds fed with NC + XyPro and NC + BMD were heavier (P < 0.05) than birds fed with NC. Improvement in feed conversion ratio (FCR) (P = 0.0001) was observed from 1 to 42 days by ~3 points in both NC + XyPro and NC + BMD compared to NC. The NC + XyPro reduced lesion scores by 66% compared to PC and NC. Litter C. perfringens cell count was reduced by ~16% with supplementation of XyPro or BMD. It can be concluded that a blend of xylanase (10 XU/g feed) and Bacillus spp. [1 × 10⁵ colony forming units (CFU)/g feed] can be used as an alternative to AGP in low-energy broiler diets.

Selection for Favorable Health Traits: A Potential Approach to Cope with Diseases in Farm Animals

Disease is a global problem for animal farming industries causing tremendous economic losses (>USD 220 billion over the last decade) and serious animal welfare issues. The limitations and deficiencies of current non-selection disease control methods (e.g., vaccination, treatment, eradication strategy, genome editing, and probiotics) make it difficult to effectively, economically, and permanently eliminate the adverse influences of disease in the farm animals. These limitations and deficiencies drive animal breeders to be more concerned and committed to dealing with health problems in farm animals by selecting animals with favorable health traits. Both genetic selection and genomic selection contribute to improving the health of farm animals by selecting certain health traits (e.g., disease tolerance, disease resistance, and immune response), although both of them face some challenges. The objective of this review was to comprehensively review the potential of selecting health traits in coping with issues caused by diseases in farm animals. Within this review, we highlighted that selecting health traits can be applied as a method of disease control to help animal agriculture industries to cope with the adverse influences caused by diseases in farm animals. Certainly, the genetic/genomic selection solution cannot solve all the disease problems in farm animals. Therefore, management, vaccination, culling, medical treatment, and other measures must accompany selection solution to reduce the adverse impact of farm animal diseases on profitability and animal welfare.

A Single Faecal Microbiota Transplantation Altered the Microbiota of Weaned Pigs

Weaning is a stressful time for piglets, often leading to weight loss and is associated with increased morbidity and mortality. A leading cause for these post-weaning problems is enteric dysbiosis and methods to improve piglet health at this crucial developmental stage are needed. This study aimed to determine whether an enteric dysbiosis caused by weaning could be corrected via a faecal microbiota transplantation (FMT) from healthy piglets from a previous wean. Two or four focal piglets per litter were assigned to one of two treatments; FMT two days post weaning (n = 21; FMT) or a control which received saline two days post weaning (n = 21; CON). FMT consisted of homogenised donor faeces administered orally at 3 mL/kg. Weaning occurred at 18 days of age and weights and faecal samples were collected on days 18, 20, 24 and 35. 16S rRNA amplicon analysis was used to assess the faecal microbiota of piglets. FMT increased Shannon’s diversity post weaning (p < 0.001) and reduced the scratch score observed at 24 days of age (p < 0.001). The bacterial populations significantly differed in composition at each taxonomic level. In FMT pigs, significant increases in potentially pathogenic Escherichia coli were observed. However, increases in beneficial bacteria Lactobacillus mucosae and genera Fibrobacteres and Bacteroidetes were also observed in FMT treated animals. To our knowledge, this is the first study to observe a significant effect on piglet faecal microbiota following a single FMT administered post weaning. Therefore, FMT post weaning can potentially alleviate enteric dysbiosis.

Systematic review of an intervention: the use of probiotics to improve health and productivity of calves

The aims of this study were to undertake a systematic review and meta-analysis of the types of probiotic formulations that are commercially available and to critically appraise the available evidence for the effectiveness of probiotics in improving the health and productivity of calves. Relevant papers were identified to answer the question: 'In calves aged between birth to one year, is the use of probiotics associated with changes in haematological or biochemical parameters, faecal bacteria counts, average daily live weight gain, dry matter intake, or feed conversion ratio?' The search of the literature yielded 67 studies that fit the primary screening criteria. Included studies were assessed for bias and confounding using a predefined risk assessment tool adapted from the Cochrane Collaboration's tool for assessing risk of bias in randomised trials and GRADE guidelines. Meta-analysis was performed using Review Manager and R. Random sequence generation was low in more than 59 % of studies. Risk of allocation concealment and performance bias were largely unclear in over 68 % of studies. Calves fed probiotics had increased average daily live weight gains (ADG) from birth to weaning (mean difference [MD] = 83.14 g/d 95 % CI = 58.36-107.91, P < 0.001) compared with calves on a control diet. Calf age reduced the level of heterogeneity of the effect of probiotics on ADG for calves between one to three weeks of age (τ² = 73.15; I² = 4%; P = 0.40) but not for calves older than three weeks of age (τ² = 2892.91; I² = 73 %; P < 0.001). Feed conversion ratio (FCR) was lower for calves on probiotics (MD = -0.13 kg of dry matter intake (DMI) to kg of live weight (LW) gain, 95 % CI = -0.17 to -0.09, P < 0.001), and the heterogeneity of effect was large in younger aged calves (τ² = 0.05; I² = 78 %; P = 0.03). The risk of bias regarding the methodology in the included studies was high. The quality of evidence for each outcome was categorised as moderate. There is sufficient data to support the effectiveness of probiotic use in some applications such as for the improvement of performance and productivity parameters of calves. However, the evidence is weak for other potential probiotic uses in calves such as improved health and reduced risk of disease. Therefore, the existing data are inconclusive and do not support the use of probiotics as an alternative to antimicrobials to improve calf health and productivity.

Effects of Diutina rugosa SD-17 on growth performance, intestine morphology, and immune status of chickens

Probiotics are considered the preferred alternatives to antibiotics for growth promotion and disease prevention. Previous studies have confirmed that Diutina rugosa SD-17 has the potential as a probiotic. We evaluated the probiotic effect of D. rugosa SD-17 on 360 one-day-old Hy-line brown chickens that were divided into 2 groups, and each group contained 6 replicate pens with 30 birds per pen. The chickens were fed with basal diet supplemented with or without D. rugosa SD-17, and the effects of D. rugosa SD-17 on growth performance, intestine morphology, and immune status were assessed. Body weight was significantly improved from week 3 to 6 (P < 0.05), and the feed conversion ratio was significantly improved in weeks 1 and 2 (P < 0.001). The length of the duodenum was lengthened significantly in week 3 (P < 0.05), and supplementation of D. rugosa SD-17 significantly increased villus height and villus height to crypt depth ratio in the ileum in week 3 (P < 0.05). Expressions of tight-junction-related genes of zonula occludens-2 and occludin in the ileum were significantly increased (P < 0.05). The proliferation capacity of blood lymphocytes stimulated by concanavalin A was significantly enhanced (P < 0.05), and the proportion of helper T (Th) cells increased significantly (P < 0.05). Expressions of Th1 cell markers IL-2 and interferon (IFN)-γ and immune-related genes of IL-1β, transforming growth factor-β, and IFN-γ in ileum were significantly increased (P < 0.05). These results indicated that D. rugosa SD-17 improved the growth and regulated immunity of chickens, and could be optimized for use as a feed additive for livestock and poultry.

Effect of a direct-fed microbial and prebiotic on performance and intestinal histomorophology of turkey poults challenged with Salmonella and Campylobacter

Salmonella and Campylobacter are leading human foodborne pathogens commonly associated with poultry and poultry products, and several methods to control these pathogens have been applied to poultry production. This study was conducted to evaluate the effect of CALSPORIN, (CSP), a direct-fed microbial (DFM), and yeast cell wall (Saccharomyces cervisiae, IMW50, a mannanoligosaccharide (MOS)-based prebiotic, on performance, levels of Salmonella and Campylobacter in the feces, and intestinal histomorphometry in turkey poults. A 21-day battery cage study was conducted using 4 dietary treatments, including: an unsupplemented basal diet (corn and soybean-based) as negative control (NC); basal diet supplemented with 0.05% DFM; basal diet supplemented with 0.05% MOS; and basal diet supplemented with 0.05% mixture of DFM and MOS at equal proportions. Female Large White turkey poults (n = 336) were randomly distributed in 6 electrically-heated battery cages with 4 treatments and 12 replicates per treatment (7 poults per replicate pen). The first 16 pens were not inoculated with bacteria, while poults in pens 17 to 32 were orally challenged at day 7 with 105 CFU Salmonella Heidelberg and the poults in pens 33 to 48 were orally challenged at day 7 with 105 CFU Campylobacter jejuni. Feed consumption, body weight, and feed conversion ratio were measured weekly and at the end of the experiment. At day 21, fresh fecal samples from each pen were collected for Salmonella and Campylobacter enumeration and ileal tissue samples were collected from 1 bird per pen for histomorphology examination. DFM and MOS supplementation was accompanied with reduced levels of Salmonella shed by the treated birds compared to the control group, and with increased body weight (P ≤ 0.05). The surface area of villi increased in the MOS-supplemented group compared to the control group (P ≤ 0.05). There was a significant difference in V:C ratio between supplemented groups and control group (P ≤ 0.05). Based on these results, there is potential for CALSPORIN and IMW50 to reduce Salmonella shedding in feces, enhance ileal mucosal health, and improve growth performance of turkey poults.

Beneficial roles of probiotics on the modulation of gut microbiota and immune response in pigs

The importance of probiotics in swine production is widely acknowledged as crucial. However, gaps still remain in the exact roles played by probiotics in modulation of gut microbiota and immune response. This study determined the roles of probiotic Lactobacillus plantarum strain JDFM LP11in gut microbiota modulation and immune response in weaned piglets. L. plantarum JDFM LP11 increased the population of lactic acid bacteria in feces and enhanced the development of villi in the small intestine. Metagenome analysis showed that microbial diversity and richness (Simpson, Shannon, ACE, Chao1) and the relative abundance of the Firmicutes were higher in weaned piglets fed probiotics. Five bacterial families were different in the relative abundance, especially; Prevotellaceae occupied the largest part of microbial community showed the most difference between two groups. Transcriptome analysis identified 25 differentially expressed genes using RNA-sequencing data of the ileum. Further gene ontology and immune DB analysis determined 8 genes associated with innate defense response and cytokine production. BPI, RSAD2, SLPI, LUM, OLFM4, DMBT1 and C6 genes were down-regulated by probiotic supplementation except PLA2G2A. PICRUSt analysis predicting functional profiling of microbial communities indicated branched amino acid biosynthesis and butyrate metabolism promoting gut development and health were increased by probiotics. Altogether, our data suggest that L. plantarum JDFM LP11 increases the diversity and richness in the microbial community, and attenuates the ileal immune gene expression towards gut inflammation, promoting intestinal development in weaned piglets.

Antibiotic use in food animals worldwide, with a focus on Africa: Pluses and minuses

Antibiotics are frequently used in food animal production in developing countries to promote the well-being and growth of animals. This practice provides some economic benefits to producers and consumers at large. Nevertheless, this practice is also associated with a number of concerns. A major concern has been that repeatedly exposing these animals to small doses of antibiotics contributes significantly to antimicrobial resistance, since a good fraction of the antibiotics used are the same or surrogates of antibiotics used in human therapeutic practices. Studies over decades have shown an explicit relationship between antimicrobial use and antimicrobial resistance in veterinary science. Many antibiotics can be purchased over the counter in African countries, and antibiotic resistance is an important issue to address in this region. This review examines some of the risks and benefits associated with antibiotic use in food animals. We conclude that the use of antibiotics in food animal production constitutes a major contributing factor to the current antimicrobial resistance crisis and that antibiotics should only be used for the treatment of sick animals based on prior diagnosis of disease.

Purification and Characterization of a Novel Anti-Campylobacter Bacteriocin Produced by Lactobacillus curvatus DN317

The lactic acid bacteria (LAB) microbiota of Saudi chicken ceca was determined. From 60 samples, 204 isolates of lactic acid bacteria were obtained. Three isolates produced antimicrobial activities against Campylobacter jejuni, Listeria monocytogenes, and Bacillus subtilis. The isolate DN317, which had the highest activity against Campylobacter jejuni ATCC 33560, was identified as Lactobacillus curvatus (GenBank accession numbers: KX353849 and KX353850). Full inhibitory activity was observed after a 2-h incubation with the supernatant at pH values between 4 and 8. Only 16% of the activity was conserved after a treatment at 121 °C for 15 min. The use of proteinase K, pepsin, chymotrypsin, trypsin, papain, and lysozyme drastically reduced the antimicrobial activity. However, lipase, catalase, and lysozyme had no effect on this activity. The active peptide produced by Lactobacillus curvatus DN317 was purified by precipitation with an 80% saturated ammonium sulfate solution, and two steps of reversed phase HPLC on a C18 column. The molecular weight of this peptide was 4448 Da as determined by MALDI-ToF. N-terminal sequence analysis using Edman degradation revealed 47 amino acid residues (UniProt Knowledgebase accession number C0HK82) revealing homology with the amino acid sequences of sakacin P and curvaticin L442. The antimicrobial activity of the bacteriocin, namely curvaticin DN317, was found to be bacteriostatic against Campylobacter jejuni ATCC 33560. The use of microbial antagonism by LAB is one of the best ways to control microorganisms safely in foods. This result constitutes a reasonable advance in the antimicrobial field because of its potential applications in food technology.

Using probiotics to improve swine gut health and nutrient utilization

To maintain a healthy gut is definitely key for a pig to digest and absorb dietary nutrients efficiently. A balanced microbiota (i.e., a healthy micro-ecosystem) is an indispensable constituent of a healthy gut. Probiotics, the live microorganisms which, when administered in adequate amounts, confer good health benefits onto the host, are a category of feed additives that can be used to replenish the gut microbial population while recuperating the host immune system. Besides their antitoxin and diarrhea reduction effects, dietary supplementation of probiotics can improve gut health, nutrient digestibilities and, therefore, benefit nutrient utilization and growth performance of pigs. Current knowledge in the literature pertinent to the beneficial effects of utilizing various probiotics for swine production has been comprehensively reviewed, and the safety and the risk issues related to probiotic usage have also been discussed in this paper. Considering that the foremost cost in a swine operation is feed cost, feed efficiency holds a very special, if not the paramount, significance in commercial swine production. Globally, the swine industry along with other animal industries is moving towards restricting and eventually a total ban on the usage of antibiotic growth promoters. Therefore, selection of an ideal alternative to the in-feed antibiotics to compensate for the lost benefits due to the ban on the antibiotic usage is urgently needed to support the industry for profitable and sustainable swine production. As is understood, a decision on this selection is not easy to make. Thus, this review paper aims to provide some much needed up-to-date knowledge and comprehensive references for swine nutritionists and producers to refer to before making prudent decisions and for scientists and researchers to develop better commercial products.

Effect of fermented broth from lactic acid bacteria on pathogenic bacteria proliferation

In this study, the effect that 5 fermented broths of lactic acid bacteria (LAB) strains have on the viability or proliferation and adhesion of 7 potentially pathogenic microorganisms was tested. The fermented broth from Lactococcus lactis C660 had a growth inhibitory effect on Escherichia coli K92 that reached of 31%, 19% to Pseudomonas fluorescens, and 76% to Staphylococcus epidermidis. The growth of Staph. epidermidis was negatively affected to 90% by Lc. lactis 11454 broth, whereas the growth of P. fluorescens (25%) and both species of Staphylococcus (35% to Staphylococcus aureus and 76% to Staph. epidermidis) were inhibited when they were incubated in the presence of Lactobacillus casei 393 broth. Finally, the fermented broth of Lactobacillus rhamnosus showed an inhibitory effect on growth of E. coli K92, Listeria innocua, and Staph. epidermidis reached values of 12, 28, and 76%, respectively. Staphylococcus epidermidis was the most affected strain because the effect was detected from the early stages of growth and it was completely abolished. The results of bacterial adhesion revealed that broths from Lc. lactis strains, Lactobacillus paracasei, and Lb. rhamnosus caused a loss of E. coli K92 adhesion. Bacillus cereus showed a decreased of adhesion in the presence of the broths of Lc. lactis strains and Lb. paracasei. Listeria innocua adhesion inhibition was observed in the presence of Lb. paracasei broth, and the greatest inhibitory effect was registered when this pathogenic bacterium was incubated in presence of Lc. lactis 11454 broth. With respect to the 2 Pseudomonas, we observed a slight adhesion inhibition showed by Lactobacillus rhamnosus broth against Pseudomonas putida. These results confirm that the effect caused by the different LAB assayed is also broth- and species-specific and reveal that the broth from LAB tested can be used as functional bioactive compounds to regulate the adhesion and biofilm synthesis and ultimately lead to preventing food and clinical contamination and colonization of E. coli K92, B. cereus, and Ls. innocua.

A prebiotic matrix for encapsulation of probiotics: physicochemical and microbiological study

This work aims to develop an encapsulated oral-synbiotic supplement by studying the effect of adding inulin in alginate beads and observing its ability to protect three probiotic strains: Pediocucus acidilactici, Lactobacillus reuteri and Lactobacillus salivarius. Beads of different inulin concentrations 0%, 5%, 10%, 15% and 20% (w/v) in 2% (w/v) alginate solution were prepared by the extrusion/ionotropic gelation method. Polymer distribution within beads was characterised using confocal laser scanning microscopy. Interactions between alginate and inulin were monitored by Fourier transform infra-red spectroscopy (FTIR). Effect of encapsulation on viability, antimicrobial ability, acid tolerance and bile tolerance of probiotic strains were investigated. Antimicrobial and probiotic properties of bacterial strains were not affected by encapsulation. Bacterial protection against acidity was increased by adding inulin. Beads with 5% w/v inulin were the most effective in bacterial protection against bile-salts. To our knowledge, this work is the first to use such high concentrations of inulin.

In vitro probiotic profile based selection of indigenous actinobacterial probiont Streptomyces sp. JD9 for enhanced broiler production

The present study was undertaken to select exclusive indigenous actinobacterial probiont for broiler health improvement based on in vitro probiotic potentials. In total, 18 actinobacterial cultures isolated from chicken were screened for survivability (resistance to low pH, pepsin, bile and pancreatin), colonization (auto-aggregation, hydrophobicity and co-aggregation) and safety (antibiotic susceptibility and non-haemolytic activity). Ten cultures showed excellent viability at pH 2 and most of the acid-tolerant isolates exhibited resistance to pepsin (3 mg/mL), bile (0.3%) and pancreatin (1 mg/mL). Besides, the examined isolates displayed efficient adhesion properties. All the isolates were susceptible to 9 different antibiotics and none of them exhibited β-haemolytic activity. Moreover, the culture JD9 revealed remarkable probiotic features compared to the other isolates, which was identified as Streptomyces sp. JD9 (KF878075). Taken together, the present study suggests that the probiont Streptomyces sp. JD9 could potentially be used in broiler practices as a feed additive to facilitate enhanced broiler production.

Increase of the adhesion ability and display of a rumen fungal xylanase on the cell surface of Lactobacillus casei by using a listerial cell-wall-anchoring protein

BACKGROUND

Lactobacillus, which has great adhesion ability to intestinal mucosa and is able to hydrolyse plant cell walls, can be used more efficiently as a feed additive. To increase the adhesion ability and display a fungal xylanase on the cell surface of Lactobacillus casei, the Listeria monocytogenes cell-wall-anchoring protein gene, mub, was introduced into L. casei ATCC 393 cells and used as a fusion partner to display the rumen fungal xylanase XynCDBFV on the cell surface of the transformed strains.

RESULTS

The transformed strain L. casei pNZ-mub, which harboured mub gene, displayed recombinant Mub on its cell surface and showed greater adhesion ability to Caco-2 cells than the parental strain. The transformed strain L. casei pNZ-mub/xyn, which harboured mub-xynCDBFV fusion gene, acquired the capacity to break down oat spelt xylan and exhibited greater competition ability against the adhesion of L. monocytogenes to Caco-2 cells, in comparison with the parental strain.

CONCLUSION

Mub has a potential to be used as a fusion partner to display heterologous proteins on the cell surface of Lactobacillus. Moreover, this is the first report of the successful display of xylanase on the cell surface of Lactobacillus.

Probiotics: a new way to fight bacterial pulmonary infections?

Antibiotics, of which Fleming has identified the first representative, penicillin, in 1928, allowed dramatical improvement of the treatment of patients presenting with infectious diseases. However, once an antibiotic is used, resistance may develop more or less rapidly in some bacteria. It is thus necessary to develop therapeutic alternatives, such as the use of probiotics, defined by the World Health Organization (WHO) as "micro-organisms which, administered live and in adequate amounts, confer a benefit to the health of the host". The scope of these micro-organisms is broad, concerning many areas including that of infectious diseases, especially respiratory infections. We describe the rational use of probiotics in respiratory tract infections and detail the results of various clinical studies describing the use of probiotics in the management of respiratory infections such as nosocomial or community acquired pneumonia, or on specific grounds such as cystic fibrosis. The results are sometimes contradictory, but the therapeutic potential of probiotics seems promising. Implementing research to understand their mechanisms of action is critical to conduct therapeutic tests based on a specific rational for the strains to be used, the dose, as well as the chosen mode and rhythm of administration.

Effect of the Combined Probiotics on Inhibiting Pathogenic Escherichia coli Prolification

The study on the combined probiotics to replace antibiotics becomes more and more important because the by-effects and appearance of “superbug” from abuse of antibiotics in human life and animal production. In order to get the effective combined probiotics for replacing antibiotics and inhibiting pathogenicEscherichia coli(E. coli) prolification, 3 strains ofBacillus subtilis(B. subtilis, named as B1, B2 and B3) were used to determine the pre-combination with experimental design (3 factors×4 levels), and then the pre-combination ofB. subtiliswas combined withLactobacillus casei(L. casei) andHansenula anomala(H. anomala) to achieve the most effective combined probiotics with the same design. The results indicated that the pre-combination ratio of B1, B2 and B3 was 0:1:1, and the most effective combination ratios of the pre-combination,L. caseiandH. anomalawere 0:1:1, 1:3:0, 2:2:3, 2:3:2, respectively (P<0.05). In addition, the incubating groups containingL. caseihad better effect on inhibitingE. coliprolification than those withoutLactobacillus, indicating thatLactobacillushad the best effect on inhibitingE. coliprolification, compared with other bacteria.

Expression of Lactobacillus reuteri Pg4 collagen-binding protein gene in Lactobacillus casei ATCC 393 increases its adhesion ability to Caco-2 cells

The collagen-binding protein gene cnb was cloned from the probiotic Lactobacillus reuteri strain Pg4. The DNA sequence of the cnb gene (792 bp) has an open reading frame encoding 263 amino acids with a calculated molecular weight of 28.5 kDa. The cnb gene was constructed so as to constitutively express under the control of the Lactococcus lactis lacA promoter and was transformed into Lactobacillus casei ATCC 393, a strain isolated from dairy products with poor ability to adhere to intestinal epithelial cells. Confocal immunofluorescence microscopic and flow cytometric analysis of the transformed strain Lb. casei pNZ-cnb indicated that Cnb was displayed on its cell surface. Lb. casei pNZ-cnb not only showed a higher ability to adhere to Caco-2 cells but also exhibited a higher competition ability against Escherichia coli O157:H7 and Listeria monocytogenes adhesion to Caco-2 cells than Lb. casei ATCC 393.

Effect of enzyme supplementation and acidification of diets on nutrient digestibility and growth performance of broiler chicks

Two experiments were conducted to examine the effects of alpha-galactosidase supplementation and acidification of diets on nutrient digestibility and growth performance of broiler chicks. In experiment 1, dietary treatments consisted of feeding a low-energy basal diet (2.74 Mcal of ME/kg) alone, the basal diet supplemented with 1,724 units of alpha-galactosidase per kg, the basal diet supplemented with 2% citric acid, or the basal diet supplemented with both. alpha-Galactosidase significantly increased feed intake, weight gain, AME(n) of the diets, and retention of CP and neutral detergent fiber (NDF) (P < 0.05). Citric acid significantly increased the retention of DM, CP, and NDF, but decreased feed intake and weight gain. The greatest values for DM and NDF retention and for AME(n) were obtained with the combination of alpha-galactosidase plus citric acid. In experiment 2, chicks were fed diets with 2 levels of energy (2.74 or 3.11 Mcal/kg), 2 levels of citric acid (0 or 1.5%), and 2 levels of alpha-galactosidase (0 or 1,724 units/kg) in a 2 x 2 x 2 factorial arrangement of treatments. alpha-Galactosidase significantly increased the reducing sugar concentration in the crop content, whereas citric acid decreased the pH and increased the reducing sugar concentration in the crop content. Citric acid decreased the gain to feed ratio in the absence but not in the presence of alpha-galactosidase. The data from these studies indicate that acidification of diet improves the efficacy of alpha-galactosidase.

Selection of Lactobacillus sp. PSC101 that produces active dietary enzymes such as amylase, lipase, phytase and protease in pigs

This study was carried out to screen lactic acid bacteria that produce active dietary enzymes, such as amylase, lipase, phytase, and protease, using a two-step process in pigs. We isolated a total of 210 and 132 strains of bacteria, grown under aerobic and anaerobic conditions, respectively, in Man Rogosa Sharpe agar containing 0.13% bile after treatment of intestinal samples at pH 3 for 30 min. From fecal samples, a total of 134 aerobic and 111 anaerobic strains were isolated in the same manner. In the second screening test, we selected four strains that produced four dietary enzymes from isolates obtained in the first screening test. Each strain was characterized as lactobacilli based on the following criteria: rod shape, negative for catalase, Gram positive, and lack of acute oral toxicity in mice. Of these four strains, we finally selected Lactobacillus spp. PSC101, which was resistant to pH 3 for 8 h and grew in the presence of 1% bile. In summary, Lactobacillus sp. PSC101 may be a strong probiotic candidate in swine due to its resistance to both acid and bile, its production of dietary enzymes that promote animal growth, and its non-toxic nature in mice.

Coexpression of rumen microbial β-glucanase and xylanase genes in Lactobacillus reuteri

The aim of this study was to clone and coexpress two rumen fibrolytic enzyme genes in Lactobacillus reuteri. The ability of the genetically modified strain to degrade beta-glucan and xylan was evaluated. The Fibrobacter succinogenes beta-glucanase (1,3-1,4-beta-D: -glucan 4-glucanohydrolase [EC 3.2.1.73]) gene and the Neocallimastix patriciarum xylanase gene, xynCDBFV, were constructed to coexpress and secrete under control of the Lactococcus lactis lacA promoter and its secretion signal and then transformed into L. reuteri Pg4, a strain isolated from the gastrointestinal tract of broiler chickens. The transformed L. reuteri strain acquired the capacity to break down soluble beta-glucan and xylan. The introduction of the recombinant plasmids and production of beta-glucanase and xylanase did not affect cell growth. To the best of our knowledge, this is the first report of coexpression of rumen microbial fibrolytic enzyme genes in L. reuteri.

Enterococcus faecium EK13--an enterocin a-producing strain with probiotic character and its effect in piglets

The experiment was conducted to determine the effects of the inoculation of the probiotic and enterocin A-producing strain Enterococcus faecium EK13 on selected parameters of metabolic profile, gut microflora, growth, and health in newborn piglets of Slovak White Improved. Piglets for study were divided into two groups: one group (EK13 group, n=8) received strain EK13 per os once daily for 7 days (2ml per piglet, 10(9)CFU/mL of saline buffer). The control group of piglets (n=7) was given placebo-saline buffer. The experiment lasted 14 days. After 7 days, strain EK13 reached 9.8 log(10) CFU/g in faeces of E. faecium EK13 treated piglets while counts of Escherichia coli were significantly lower (P<0.01) than in piglets of the control group. The concentrations of total serum protein, calcium, haemoglobin, haematocrit, red blood cell count and index of phagocytic activity of leukocytes were significantly higher after application of strain EK13. On the other hand, cholesterol was significantly lower in the EK13 group of animals. On day 14, piglets were killed and samples of intestinal contents were taken. Total counts of bacteria in the intestinal contents (jejunum, ileum, caecum, colon) were not significantly influenced. The pH value was significantly lower (P<0.05) only in duodenum of piglets receiving E. faecium EK13. There was a significant higher concentration of lactic acid (P<0.01) and propionic acid in the colon (P<0.001) of the EK13 group. Application of E. faecium EK13 did not influence the daily body weight gain significantly.

Direct cloning of a xylanase gene from the mixed genomic DNA of rumen fungi and its expression in intestinal Lactobacillus reuteri

A relatively newly defined xylanase gene, xynR8, was obtained directly from a mixed DNA sample prepared from unpurified rumen fungal cultures by PCR amplification. The DNA sequence of xynR8 revealed that the gene was 884 bp in size and encoded amino acid sequences with a molecular weight of 27.9 kDa. XynR8 belonged to glycosyl hydrolase family 11, and the catalytic site residues were also found in its amino acid sequence. The main hydrolysis products of XynR8 were xylobiose, xylotriose and xylotetrose, which indicated that it belonged to the endoxylanases. The xynR8 gene was constructed so as to express and secrete under the control of the Lactococcus lactis lac A promoter and its secretion signal, and was transformed into L. reuteri Pg4, a strain isolated from the gastrointestinal tract of broiler chickens. The L. reuteri transformants harboring xynR8 not only acquired the capacity to break down xylan, but also maintained their high adhesion efficiency to mucin and mucus and their resistance to bile salts and acid.

Expression of rumen microbial fibrolytic enzyme genes in probiotic Lactobacillus reuteri

This study was aimed at evaluating the cloning and expression of three rumen microbial fibrolytic enzyme genes in a strain of Lactobacillus reuteri and investigating the probiotic characteristics of these genetically modified lactobacilli. The Neocallimastix patriciarum xylanase gene xynCDBFV, the Fibrobacter succinogenes beta-glucanase (1,3-1,4-beta-D-glucan 4-glucanohydrolase [EC 3.2.1.73]) gene, and the Piromyces rhizinflata cellulase gene eglA were cloned in a strain of L. reuteri isolated from the gastrointestinal tract of broilers. The enzymes were expressed and secreted under the control of the Lactococcus lactis lacA promoter and its secretion signal. The L. reuteri transformed strains not only acquired the capacity to break down soluble carboxymethyl cellulose, beta-glucan, or xylan but also showed high adhesion efficiency to mucin and mucus and resistance to bile salt and acid.

Enumeration of specific bacterial populations in complex intestinal communities using quantitative PCR based on the chaperonin-60 target

We used qPCR and the target gene chaperonin-60 (cpn60) to enumerate Clostridium perfringens genomes in DNA extracts from contents of the chicken gastrointestinal tract with the aim of optimizing this methodology to enumerate any bacterium of interest. To determine the most accurate protocols for determining target species abundance, we compared various DNA extraction methods in combination with four methods for producing standard curves. Factors affecting accuracy included the co-purification of PCR inhibitors and/or fluorescence quenchers and the yield of target DNA in the extract. Anion exchange chromatography of the spiked test samples enabled accurate enumeration of C. perfringens using a standard curve comprised of a plasmid containing a fragment of C. perfringens cpn60. We used qPCR to enumerate C. perfringens and other intestinal bacteria in ileum and cecum samples from chickens that had been challenged with C. perfringens and compared the results with viable counts on corresponding selective agars. We conclude that qPCR-based molecular enumeration of target species in the gastrointestinal tract is feasible, but care must be taken in order to mitigate the effects of confounding factors that can affect the apparent cell count.

Effects of probiotics on the composition of the intestinal microbiota following antibiotic therapy

The effects of probiotic supplementation on the intestinal re-growth microbiota following antibiotic therapy were studied in a double-blind placebo-controlled study. In the placebo group, numbers of facultative anaerobes and enterobacteria increased significantly, and at day 35 the numbers were significantly higher in the placebo group than in the active group; in the active group, the numbers of bacteroides increased significantly. Although the numbers of enterococci in both groups did not change, in the placebo group the number of patients harbouring antibiotic-resistant enterococci post therapy increased significantly. There was no change in the incidence rate of antibiotic resistance among the patients in the probiotic group.

Incorporation of galactomannans in the diet of newly weaned piglets: Effect on bacteriological and some morphological characteristics of the small intestine

In search of substances replacing antibiotics as growth promoters for farm animals, non-digestible oligosaccharides (NDO) or non-starch polysaccharides (NSP) have been proposed as possible alternatives. In this context, the influence of galactomannans on bacteriological and morphological aspects of the gastrointestinal tract in weanling pigs was investigated. Four groups of five newly weaned piglets received one of the following diets: control feed (C), C supplemented with guar gum (1%), C supplemented with locust bean gum (1%) and C supplemented with 10% of carob tree seeds meal as source of locust bean gum. The animals were euthanized after 11-12 days and digesta were sampled in stomach, jejunum (proximal and distal) and caecum, while mucosal scrapings and ring shaped tissue samples were taken of proximal and distal jejunum. On these samples bacteriological, biochemical and morphological determinations were carried out. Total count of bacteria in digesta and mucosal scrapings was not influenced by the different diets, with the exception of the proximal jejunum where a small decrease (0.5 log10 CFU) was noted with the guar gum and carob tree seeds diet. The number of E. coli increased by feeding both gums and carob tree seeds. With the latter diet, higher counts of streptococci were observed. In agreement with the lower concentration of lactic acid in jejunal contents, guar gum decreased the number of lactobacilli. Locust bean gum decreased the molar proportion of acetate in caecal contents while butyrate and valerate were augmented. Feeding the carob tree seeds resulted in shorter villi and a lower villus height/crypt depth ratio in the jejunum mucosa, which was an indication for a faster renewal rate of the epithelium. Both locust bean gum feeds significantly lowered the mitotic index in the crypts of the small intestine. Only with the carob tree seeds diet, viscosity of jejunal contents was increased. In conclusion, the effects of the addition of 1% of pure guar gum or locust bean gum were inconsistent and not very outspoken, whereas 10% of carob tree seeds meal in the diet resulted in influences on intestinal characteristics at the bacteriological and morphological level.

Development of a strain-specific assay for detection of viable Lactobacillus sp. HOFG1 after application to cattle feed

A strain-specific assay was developed for the detection of viable Lactobacillus on cattle feed. The DNA sequences of the 16S rRNA gene and four different 16S/23S rRNA intergenic spacer regions (ISR) from Lactobacillus sp. HOFG1 were determined. Based on these sequences, a strain-specific primer was designed for the amplification of one of the ISRs. When combined with a Lactobacillus group primer, the polymerase chain reaction (PCR) assay detected only Lactobacillus sp. HOFG1 and not other closely related L. animalis or L. murinus strains. The feed assay uses a combination of enrichment culturing and PCR to detect and enumerate viable Lactobacillus sp. HOFG1 after its application onto cattle feed. The high degree of primer specificity and use of selective culturing allows for the detection of viable Lactobacillus which is useful in tracking bacteria applied to complex feed mixtures that contain a high background of endogenous bacteria.