Review: Are there indigenous Saccharomyces in the digestive tract of livestock animal species? Implications for health, nutrition and productivity traits.

All livestock animal species harbour complex microbial communities throughout their digestive tract that support vital biochemical processes, thus sustaining health and productivity. In part as a consequence of the strong and ancient alliance between the host and its associated microbes, the gut microbiota is also closely related to productivity traits such as feed efficiency. This phenomenon can help researchers and producers develop new and more effective microbiome-based interventions using probiotics, also known as direct-fed microbials (DFMs), in Animal Science. Here, we focus on one type of such beneficial microorganisms, the yeast Saccharomyces. Saccharomyces is one of the most widely used microorganisms as a DFM in livestock operations. Numerous studies have investigated the effects of dietary supplementation with different species, strains and doses of Saccharomyces (mostly Saccharomyces cerevisiae) on gut microbial ecology, health, nutrition and productivity traits of several livestock species. However, the possible existence of Saccharomyces which are indigenous to the animals' digestive tract has received little attention and has never been the subject of a review. We for the first time provide a comprehensive review, with the objective of shedding light into the possible existence of indigenous Saccharomyces of the digestive tract of livestock. Saccharomyces cerevisiae is a nomadic yeast able to survive in a broad range of environments including soil, grass and silages. Therefore, it is very likely that cattle and other animals have been in direct contact with this and other types of Saccharomyces throughout their entire existence. However, to date, the majority of animal scientists seem to agree that the presence of Saccharomyces in any section of the gut only reflects dietary contamination; in other words, these are foreign organisms that are only transiently present in the gut. Importantly, this belief (i.e. that Saccharomyces come solely from the diet) is often not well grounded and does not necessarily hold for all the many other groups of microbes in the gut. In addition to summarizing the current body of literature involving Saccharomyces in the digestive tract, we discuss whether the beneficial effects associated with the consumption of Saccharomyces may be related to its foreign origin, though this concept may not necessarily satisfy the theories that have been proposed to explain probiotic efficacy in vivo. This novel review may prove useful for biomedical scientists and others wishing to improve health and productivity using Saccharomyces and other beneficial microorganisms.

Probiotics, mechanisms of action, and clinical perspectives for diarrhea management in children.

Infectious diarrhea is the second most common cause of morbidity and mortality in children under 5 years of age in the underdeveloped areas of the world. Conventional treatment consists of rehydration, which may be coupled with antimicrobial agents in more severe bacterial infections or with antiprotozoal agents. In the last few decades, research on the use of probiotic strains, such as Lactobacillus rhamnosus GG ATCC 53013 (LGG), Lactobacillus reuteri DSM 17938 and Saccharomyces boulardii, has gained much attention to prevent and treat diarrheal diseases. However, they are rarely used in the clinical routine, perhaps because there are still gaps in the knowledge about the effective benefit to the patient in terms of the reduction of the duration of diarrhea and its prevention. Furthermore, only a few probiotic strains are safely indicated for usage in pediatric practice. This review summarizes the current knowledge on the antimicrobial mechanisms of probiotics on distinct enteropathogens and their role in stimulating host defense mechanisms against intestinal infections. In addition, we highlight the potential of probiotics for the treatment and prevention of diarrhea in children. We conclude that the use of probiotics is beneficial for both the treatment and prevention of diarrhea in children and that the identification of other candidate probiotics might represent an important advance to a greater reduction in hospital stays and to prevent infectious diarrhea in a larger portion of this population.

The antifungal properties of peppermint and thyme essential oils misted in broiler houses

This study aimed at evaluating if essential oils misted in broiler houses reduce environmental fungi counts. The investigation was conducted in three experimental rooms, where broiler chickens were reared between 1 to 42 d of age. Every three days, the rooms were fogged with pure water (control) or with aqueous solutions of peppermint or thyme oils. On the next day, fogging samples from the air, flat surfaces, and litter were collected and quantitatively and qualitatively analysed for fungal contamination. The treatment with essential oils showed promising results. In the room fogged with thyme oil, aerial fungi growth was not as evident as in the control room, and presented the lowest average fungi count. Thyme oil was also the most effective in reducing fungi colonization on drinker surfaces and litter. The use of peppermint oil also reduced the population of air, wall, surface and litter fungi, although some exceptions were noted. Aspergillus, Penicillium, Fusarium and Saccharomyces genera were identified most frequently. The effect of essential oils was noticeable in the last two weeks, when the counts of Aspergillus sp. were 75% (thyme oil) and 46% (peppermint oil) lower in comparison with the control group. The results show that fogging broiler houses with essential oils may be an effective prevention method against fungal aerosol in broiler houses. However, further investigations to determine the synergistic effect of different oils and their compounds, and the best possible doses and methods of application in the field are needed.

The antifungal properties of peppermint and thyme essential oils misted in broiler houses

This study aimed at evaluating if essential oils misted in broiler houses reduce environmental fungi counts. The investigation was conducted in three experimental rooms, where broiler chickens were reared between 1 to 42 d of age. Every three days, the rooms were fogged with pure water (control) or with aqueous solutions of peppermint or thyme oils. On the next day, fogging samples from the air, flat surfaces, and litter were collected and quantitatively and qualitatively analysed for fungal contamination. The treatment with essential oils showed promising results. In the room fogged with thyme oil, aerial fungi growth was not as evident as in the control room, and presented the lowest average fungi count. Thyme oil was also the most effective in reducing fungi colonization on drinker surfaces and litter. The use of peppermint oil also reduced the population of air, wall, surface and litter fungi, although some exceptions were noted. Aspergillus, Penicillium, Fusarium and Saccharomyces genera were identified most frequently. The effect of essential oils was noticeable in the last two weeks, when the counts of Aspergillus sp. were 75% (thyme oil) and 46% (peppermint oil) lower in comparison with the control group. The results show that fogging broiler houses with essential oils may be an effective prevention method against fungal aerosol in broiler houses. However, further investigations to determine the synergistic effect of different oils and their compounds, and the best possible doses and methods of application in the field are needed.(AU)

Probiotics: an update / Probióticos: informações atualizadas

OBJECTIVE: Triggered by the growing knowledge on the link between the intestinal microbiome and human health, the interest in probiotics is ever increasing. The authors aimed to review the recent literature on probiotics, from definitions to clinical benefits, with emphasis on children. SOURCES: Relevant literature from searches of PubMed, CINAHL, and recent consensus statements were reviewed. SUMMARY OF THE FINDINGS: While a balanced microbiome is related to health, an imbalanced microbiome or dysbiosis is related to many health problems both within the gastro-intestinal tract, such as diarrhea and inflammatory bowel disease, and outside the gastro-intestinal tract such as obesity and allergy. In this context, a strict regulation of probiotics with health claims is urgent, because the vast majority of these products are commercialized as food (supplements), claiming health benefits that are often not substantiated with clinically relevant evidence. The major indications of probiotics are in the area of the prevention and treatment of gastro-intestinal related disorders, but more data has become available on extra-intestinal indications. At least two published randomized controlled trials with the commercialized probiotic product in the claimed indication are a minimal condition before a claim can be sustained. Today, Lactobacillus rhamnosus GG and Saccharomyces boulardii are the best-studied strains. Although adverse effects have sporadically been reported, these probiotics can be considered as safe. CONCLUSIONS: Although regulation is improving, more stringent definitions are still required. Evidence of clinical benefit is accumulating, although still missing in many areas. Misuse and use of products that have not been validated constitute potential drawbacks. .

OBJETIVO: Motivado pelo conhecimento cada vez maior da associação entre o microbioma intestinal e a saúde humana, o interesse nos probióticos vem crescendo cada vez mais. Os autores visaram analisar a última literatura a respeito dos probióticos, de definições a benefícios clínicos com ênfase nas crianças. FONTES DOS DADOS: Foi analisada a literatura relevante de pesquisas do PubMed, do CINAHL e dos últimos consensos. SÍNTESE DOS DADOS: Apesar de um equilíbrio no microbioma estar relacionado à saúde, um desequilíbrio no microbioma ou disbiose está relacionado a vários problemas de saúde no trato gastrointestinal, como diarreia e doença inflamatória intestinal, e fora do trato gastrointestinal, como obesidade e alergia. Nesse contexto, a regulamentação rigorosa dos probióticos a alegações de saúde é urgente, pois a grande maioria desses produtos é comercializada como alimentação (suplementos), alegando benefícios à saúde que frequentemente não são comprovados com evidências clinicamente relevantes. As principais indicações de probióticos são feitas na área da prevenção e tratamento de doenças gastrointestinais, porém mais dados têm sido disponibilizados a respeito de indicações extraintestinais. Pelo menos dois ensaios clínicos controlados e randomizados publicados com o probiótico comercializado na indicação declarada são a condição mínima antes de uma afirmação poder ser mantida. Atualmente, o Lactobacillus rhamnosus GG e Saccharomyces boulardii são as melhores cepas estudadas. Apesar de efeitos adversos terem sido esporadicamente relatados, os probióticos podem ser considerados seguros. CONCLUSÕES: Apesar de a regulamentação estar aumentando, ainda são necessárias definições mais rigorosas. As evidências de benefícios clínicos estão aumentando, apesar de ainda ausentes em várias áreas. O uso inadequado e a utilização de produtos não validados constituem possíveis desvantagens. .

Yeast population dynamics during prefermentative cold soak of Cabernet Sauvignon and Malbec wines.

Prefermentative cold soak is a widely used technique in red wine production, but the impact on the development of native yeast species is hardly described. The aim of this work was to analyse the dynamics and diversity of yeast populations during prefermentative cold soak in red wines. Three different temperatures (14 ± 1 °C; 8 ± 1 °C and 2.5 ± 1 °C) were used for prefermentative cold soak in Cabernet Sauvignon and Malbec grape musts. Saccharomyces and non-Saccharomyces populations during cold soak and alcoholic fermentation were analysed. In addition, the impact on chemical and sensory properties of the wines was examined. Yeast dynamics during prefermentative cold soak were temperature dependent. At 14 ± 1 °C, the total yeast population progressively increased throughout the cold soak period. Conversely, at 2.5 ± 1 °C, the yeast populations maintained stable during the same period. Prefermentative cold soak conducted at 14±1°C favoured development of Hanseniospora uvarum and Candida zemplinina, whereas cold soak conducted at 8 ± 1 °C favoured growth of Saccharomyces cerevisiae. At 2.5 ± 1 °C, no changes in yeast species were recorded. Acidity and bitterness, two sensory descriptors, appear to be related to wines produced with prefermentative cold soak carried out at 14 ± 1 °C. This fact could be associated with the increase in non-Saccharomyces during the prefermentation stage. Our results emphasise the importance of the temperature as a determinant factor to allow an increase in non-Saccharomyces population during prefermentative cold soak and consequently to modify sensorial attributes of wines as well as their sensorial impact.

Probiotics: an update.

OBJECTIVE: Triggered by the growing knowledge on the link between the intestinal microbiome and human health, the interest in probiotics is ever increasing. The authors aimed to review the recent literature on probiotics, from definitions to clinical benefits, with emphasis on children. SOURCES: Relevant literature from searches of PubMed, CINAHL, and recent consensus statements were reviewed. SUMMARY OF THE FINDINGS: While a balanced microbiome is related to health, an imbalanced microbiome or dysbiosis is related to many health problems both within the gastro-intestinal tract, such as diarrhea and inflammatory bowel disease, and outside the gastro-intestinal tract such as obesity and allergy. In this context, a strict regulation of probiotics with health claims is urgent, because the vast majority of these products are commercialized as food (supplements), claiming health benefits that are often not substantiated with clinically relevant evidence. The major indications of probiotics are in the area of the prevention and treatment of gastro-intestinal related disorders, but more data has become available on extra-intestinal indications. At least two published randomized controlled trials with the commercialized probiotic product in the claimed indication are a minimal condition before a claim can be sustained. Today, Lactobacillus rhamnosus GG and Saccharomyces boulardii are the best-studied strains. Although adverse effects have sporadically been reported, these probiotics can be considered as safe. CONCLUSIONS: Although regulation is improving, more stringent definitions are still required. Evidence of clinical benefit is accumulating, although still missing in many areas. Misuse and use of products that have not been validated constitute potential drawbacks.

Effect of probiotics on the development of dimethylhydrazine-induced preneoplastic lesions in the mice colon.

PURPOSE: To determine the effect of probiotics on the development of chemically induced (1, 2-dimethylhydrazine) colonic preneoplastic lesions, in mice. METHODS: The animals were divided into five groups. The control group was injected with carcinogen alone and the other groups also received probiotics (1- Lactobacillus delbrueckii UFV-H2b20; 2- Bifidobacterium animalis var. lactis Bb12; 3- L. delbrueckii UFV-H2b20 plus B. animalis var. lactis Bb12; and 4- Saccharomyces boulardii) administered orally in drinking water throughout fourteen weeks. RESULTS: Consumption of lactobacilli and bifidobacteria alone resulted in a significant reduction of the total number of aberrant crypt foci (55.7% and 45.1%, respectively). Significant reduction in the number of these small foci (<3 aberrant crypts) was only observed in the group treated with lactobacilli (52.2%) in comparison to control group. The number of larger foci (>3 aberrant crypts) crypts had no significant reduction. CONCLUSION: L. delbrueckii UFV-H2b20 and B. animalis var. lactis Bb12 administered alone protect colonic preneoplastic lesions in mice, while the combined treatment of these bacteria and the administration of S.boulardii were not effective in reducing such colonic lesions.

Effect of probiotics on the development of dimethylhydrazine-induced preneoplastic lesions in the mice colon

PURPOSE: To determine the effect of probiotics on the development of chemically induced (1, 2-dimethylhydrazine) colonic preneoplastic lesions, in mice. METHODS: The animals were divided into five groups. The control group was injected with carcinogen alone and the other groups also received probiotics (1- Lactobacillus delbrueckii UFV-H2b20; 2- Bifidobacterium animalis var. lactis Bb12; 3- L. delbrueckii UFV-H2b20 plus B. animalis var. lactis Bb12; and 4- Saccharomyces boulardii) administered orally in drinking water throughout fourteen weeks. RESULTS: Consumption of lactobacilli and bifidobacteria alone resulted in a significant reduction of the total number of aberrant crypt foci (55.7% and 45.1%, respectively). Significant reduction in the number of these small foci (<3 aberrant crypts) was only observed in the group treated with lactobacilli (52.2%) in comparison to control group. The number of larger foci (>3 aberrant crypts) crypts had no significant reduction. CONCLUSION: L. delbrueckii UFV-H2b20 and B. animalis var. lactis Bb12 administered alone protect colonic preneoplastic lesions in mice, while the combined treatment of these bacteria and the administration of S.boulardii were not effective in reducing such colonic lesions.

Probióticos e prebióticos na diarreia aguda: revisão / Probiotic and prebiotic in acute diarrhea: review

O adequado controle terapêutico da diarreia aguda deve promover pronta e eficaz reidratação, oferecer suporte nutricional adequado, reduzir o número de evacuações e abreviar o tempo da doença. Esta revisão tem como objetivo apresentar os resultados de estudos recentes abordando a eficácia terapêutica de probióticos e prebióticos para as causas infecciosas de diarreia aguda.

Adequate therapeutic control of acute diarrhea should promote fast and effective rehydration, offer adequate nutritional support, reduce the number of bowel movements and shorten disease duration. The objective of this review is to present the results of recent studies regarding the therapeutic efficacy of probiotics and prebiotics for the treatment of infectious, acute diarrhea.

Genome-wide gene expression of a natural hybrid between Saccharomyces cerevisiae and S. kudriavzevii under enological conditions.

The species Saccharomyces cerevisiae plays a predominant role in the wine making process. However, other species have been associated with must fermentation, such as Saccharomyces uvarum (Saccharomyces bayanus var. uvarum) or Saccharomyces paradoxus. Recently, yeast hybrids of different Saccharomyces species have also been reported as responsible for wine production. Yeast hybrids between the species S. cerevisiae×S. kudriavzevii isolated in wine fermentations show enhanced performance in low temperature enological conditions and increased production of interesting aroma compounds. In this work, we have studied the transcriptomic response in enological conditions of a S. cerevisiae×S. kudriavzevii hybrid strain and compared it with the reference species of S. cerevisiae and S. kudriavzevii. The results show that the hybrid strain presents an up-regulation of genes belonging to functional group translation and amino-acid metabolism. Moreover, key genes related to cold stress and production of glycerol and aroma compounds were also up-regulated. While some genes inherited regulation patterns from one of the parents, most of the up-regulated genes presented a new gene expression pattern, probably generated during the hybridization and adaptation process.

Adhesion to the yeast cell surface as a mechanism for trapping pathogenic bacteria by Saccharomyces probiotics.

Recently, much attention has been given to the use of probiotics as an adjuvant for the prevention or treatment of gastrointestinal pathology. The great advantage of therapy with probiotics is that they have few side effects such as selection of resistant bacteria or disturbance of the intestinal microbiota, which occur when antibiotics are used. Adhesion of pathogenic bacteria onto the surface of probiotics instead of onto intestinal receptors could explain part of the probiotic effect. Thus, this study evaluated the adhesion of pathogenic bacteria onto the cell wall of Saccharomyces boulardii and Saccharomyces cerevisiae strains UFMG 905, W303 and BY4741. To understand the mechanism of adhesion of pathogens to yeast, cell-wall mutants of the parental strain of Saccharomyces cerevisiae BY4741 were used because of the difficulty of mutating polyploid yeast, as is the case for Saccharomyces cerevisiae and Saccharomyces boulardii. The tests of adhesion showed that, among 11 enteropathogenic bacteria tested, only Escherichia coli, Salmonella Typhimurium and Salmonella Typhi adhered to the surface of Saccharomyces boulardii, Saccharomyces cerevisiae UFMG 905 and Saccharomyces cerevisiae BY4741. The presence of mannose, and to some extent bile salts, inhibited this adhesion, which was not dependent on yeast viability. Among 44 cell-wall mutants of Saccharomyces cerevisiae BY4741, five lost the ability to fix the bacteria. Electron microscopy showed that the phenomenon of yeast-bacteria adhesion occurred both in vitro and in vivo (in the digestive tract of dixenic mice). In conclusion, some pathogenic bacteria were captured on the surface of Saccharomyces boulardii, Saccharomyces cerevisiae UFMG 905 and Saccharomyces cerevisiae BY4741, thus preventing their adhesion to specific receptors on the intestinal epithelium and their subsequent invasion of the host.

Protection against increased intestinal permeability and bacterial translocation induced by intestinal obstruction in mice treated with viable and heat-killed Saccharomyces boulardii.

BACKGROUND: There are substantial evidences suggesting that probiotics can protect the gastrointestinal tract against inflammatory or infectious episodes. The effects of oral treatment with viable or heat-killed cells of Saccharomyces boulardii (Sb) on bacterial translocation, intestinal permeability, histological aspect of the ileum, and some immunological parameters were evaluated in a murine intestinal obstruction (IO) model. RESULTS: Bacterial translocation and intestinal permeability in the IO group were significantly higher when compared to a Sham group (p < 0.05). Pretreatment with both viable and heat-killed S. boulardii prevented these increases, and the data obtained for IO + Sb and IO + heat-killed Sb groups were similar to those observed in the Sham group (p > 0.05). Histological analysis showed preservation of the ileum mucosa in mice that received both forms of the yeast when compared to the lesions observed in the IO group. The levels of serum interleukin (IL)-10 and intestinal secretory immunoglobulin A (sIgA) were higher in the animals that received both yeast treatments when compared to those from IO and Sham groups. CONCLUSION: Oral treatment with viable or heat-killed cells of S. boulardii maintained intestinal integrity and modulated the immune system in a murine IO model, preventing bacterial translocation and intestinal lesions.

Probiotics in the treatment of acute rotavirus diarrhoea. A randomized, double-blind, controlled trial using two different probiotic preparations in Bolivian children.

BACKGROUND: Evidence suggests that probiotics reduce rotavirus diarrhoea duration. Although there are several probiotic strains potentially useful, daily practice is often limited by the type and number of products locally available. In general, information about combined products is scarce. In this study we compare the effect of two probiotic products in the treatment of diarrhoea in children less than 2 years of age. METHODS: A Randomized double-blind controlled clinical trial in children hospitalized for acute rotavirus diarrhoea, in the Paediatric Centre Albina Patino, Cochabamba, Bolivia.Participants were children aged 1 - 23 months, who were randomly assigned to receive one of three treatments: Oral rehydration therapy plus placebo; Oral rehydration solution plus Saccharomyces boulardii; or Oral rehydration solution plus a compound containing Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium longum and Saccharomyces boulardii. Sample size was 20 per group and the outcomes were duration of diarrhoea, of fever, of vomiting and of hospitalization. RESULTS: 64 cases finished the protocol. On admission, patients' characteristics were similar. Median duration of diarrhoea (p = 0.04) in children who received the single species product (58 hours) was shorter than in controls (84.5 hrs). Comparing children that received the single probiotic product and controls showed shorter duration of fever (18 vs 67 hrs) (p = 0.0042) and the mixed probiotic of vomiting (0 vs 42.5 hrs) (p = 0.041). There was no effect on duration of hospitalization (p = 0.31). When experimental groups were merged, statistical significance of changes increased (total duration of diarrhoea, fever and vomiting P = 0.025, P = 0.025 and P = 0.014, respectively). CONCLUSIONS: Both products decreased the duration of diarrhoea compared to oral rehydration solution alone. This decrease was significant only for the single species product which also decreased the duration of fever. With the multiple species product there was no vomiting subsequent to the initiation of treatment. The quantity of probiotic bacteria needed for optimum treatment of gastroenteritis remains to be determined, particularly when multiple species are included in the product.Trial registration: ClinicalTrials.gov ID: NCT00981877Link: https://register.clinicaltrials.gov/prs/app/action/SelectProtocol/sid/S0002653/selectaction/View/ts/2/uid/U0000N04 TRIAL REGISTRATION: Clinical trials NCT ID: NCT00981877.

[Studies of viability and vitality after freezing of the probiotic yeast Saccharomyces boulardii: physiological preconditioning effect]. / Estudios de la viabilidad y la vitalidad frente al congelado de la levadura probiótica Saccharomyces boulardii: efecto del preacondicionamiento fisiológico.

The aim of this study was to evaluate the vitality and viability of the probiotic yeast Saccharomyces boulardii after freezing/thawing and the physiological preconditioning effect on these properties. The results indicate that the specific growth rate (0.3/h(-1)) and biomass (2-3 x10(8)cells/ml) of S. boulardii obtained in flasks shaken at 28 degrees C and at 37 degrees C were similar. Batch cultures of the yeast in bioreactors using glucose or sugar-cane molasses as carbon sources, reached yields of 0.28 g biomass/g sugar consumed, after 10h incubation at 28 degrees C; the same results were obtained in fed batch fermentations. On the other hand, in batch cultures, the vitality of cells recovered during the exponential growth phase was greater than the vitality of cells from the stationary phase of growth. Vitality of cells from fed-batch fermentations was similar to that of stationary growing cells from batch fermentations. Survival to freezing at -20 degrees C and subsequent thawing of cells from batch cultures was 0.31% for cells in exponential phase of growth and 11.5% for cells in stationary phase. Pre-treatment of this yeast in media with water activity (a(w)) 0.98 increased the survival to freezing of S. boulardii cells stored at -20 degrees C for 2 months by 10 fold. Exposure of the yeast to media of reduced a(w) and/or freezing/thawing process negatively affected cell vitality. It was concluded that stress conditions studied herein decrease vitality of S. boulardii. Besides, the yeast strain studied presented good tolerance to bile salts even at low pH values.

Comparative study of Bifidobacterium animalis, Escherichia coli, Lactobacillus casei and Saccharomyces boulardii probiotic properties.

The present work investigates some probiotic properties of four different microorganisms (Bifidobacterium animalis var. lactis BB-12, Escherichia coli EMO, Lactobacillus casei and Saccharomyces boulardii). In vitro and in vivo tests were carried out to compare cell wall hydrophobicity, production of antagonistic substances, survival capacity in the gastrointestinal tract of germ-free mice without pathological consequence, and immune modulation by stimulation of Küpffer cells, intestinal sIgA and IL-10 levels. In vitro antagonism against pathogenic bacteria and yeast was only observed for the probiotic bacteria B. animalis and L. casei. The hydrophobic property of the cell wall was higher for B. animalis and E. coli EMO, and this property could be responsible for a better ability to colonize the gastrointestinal tract of germ-free mice. Higher levels of sIgA were observed mainly for S. boulardii, followed by E. coli EMO and B. animalis, and only S. boulardii induced a significant higher level of IL-10. In conclusion, for a probiotic use, S. boulardii presented better characteristics in terms of immunomodulation, and B. animalis and L. casei for antagonistic substance production. The knowledge of the different probiotic properties could be used to choice the better microorganism depending on the therapeutic or prophylactic application.

Protective effect of ions against cell death induced by acid stress in Saccharomyces.

Saccharomyces boulardii is a probiotic used to prevent or treat antibiotic-induced gastrointestinal disorders and acute enteritis. For probiotics to be effective they must first be able to survive the harsh gastrointestinal environment. In this work, we show that S. boulardii displayed the greatest tolerance to simulated gastric environments compared with several Saccharomyces cerevisiae strains tested. Under these conditions, a pH 2.0 was the main factor responsible for decreased cell viability. Importantly, the addition of low concentrations of sodium chloride (NaCl) protected cells in acidic conditions more effectively than other salts. In the absence of S. boulardii mutants, the protective effects of Na(+) in yeast viability in acidic conditions was tested using S. cerevisiae Na(+)-ATPases (ena1-4), Na(+)/H(+) antiporter (nha1Delta) and Na(+)/H(+) antiporter prevacuolar (nhx1Delta) null mutants, respectively. Moreover, we provide evidence suggesting that this protection is determined by the plasma membrane potential, once altered by low pH and low NaCl concentrations. Additionally, the absence or low expression/activity of Ena proteins seems to be closely related to the basal membrane potential of the cells.

Study of flocculent yeast performance in tower reactors for bioethanol production in a continuous fermentation process with no cell recycling.

The purpose of this study was to assess the retention ability of 12 different Saccharomyces sp. yeast strains with flocculent characteristics when inoculated in a continuous ethanol fermentation process. The system was comprised of two reactors connected in series with no cell recycling. The feeding substrate used was a synthetic medium containing glucose. The parameters assessed were total reducing sugars of the feeding substrate, total reducing sugars and ethanol at the outlet of the first and second reactors and quantification and classification of yeast population in the two reactors. The system reached yield levels of 83.53% of theoretical yield with a maximum total reducing sugars conversion of 92.68%. The conversion in this system was lower than expected. The dominant yeast in the process in both reactors, contrary to expectation, was the Saccharomyces CP6 strain which was unable to form pellets in spite of its flocculate growth.

Bacillus cereus var. toyoii and Saccharomyces boulardii increased feed efficiency in broilers infected with Salmonella enteritidis.

1. The effect on feed efficiency of two probiotics, one prepared with Saccharomyces boulardii and the other with Bacillus cereus var. toyoii, was tested in broilers infected with Salmonella enteritidis. 2. One-day-old chicks were divided at random into three groups and fed commercial feed devoid of antibiotics: group 1 was fed with non-supplemented feed, group 2 was supplemented with S. boulardii and group 3 with B. cereus. At 14 d of age the animals were challenged by the oral route with 1 x 10(7) viable S. enteritidis. 3. At d 47, average live weights were: group 1, 1.77 kg, group 2, 1.89 kg and group 3, 2.06 kg, and were significantly different. Feed conversion rates were 2.61 for group 1, 2.35 for group 2 and 2.30 for group 3. 4. We conclude that both probiotics improved feed efficiency in broilers.

[Lyophilized Saccharomyces boulardii: example of a probiotic medicine]. / Ejemplo de un medicamento probiótico: Saccharomyces boulardii liofilizada.

Saccharomyces boulardii is a natural yeast without genetic modification isolated from the bark of the litchi tree in Indochina. In its lyophilized form is an example of the called probiotic medicine. The probiotic denomination is in relation to that itself assets in the gastrointestinal tract in interrelation to that biologic environment. And is labelled as medicine because the lyophilized form has a clinical and pharmaceutical expedient included in the regulation of medicinal products in almost 100 countries.